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Speed and Danger

Speed and Danger

https://www.xkcd.com/1701

https://www.explainxkcd.com/wiki/index.php/1701:_Speed_and_Danger

[A two-axis diagram with two double headed arrows centered in the middle of the panel. Each arrow is labeled. There are four large dots in the diagram, three close together in the top left corner and one in the bottom right corner. Each dot is labeled.] [Y axis:] Top: Crashes are safe Bottom: Crashes are dangerous [X axis:] Left: Slow Right: Fast [Dots from top left to bottom right:] Normal sports NASCAR Formula One Rocket launches

In this scatter plot Randall plots the speed of several vehicles (including people on foot for "normal sports") and how disastrous a crash would be. The punchline is that space rockets travel so dangerously fast, and crashes are so utterly catastrophic, that it pushes literally every other kind of crash to the "slow and safe" corner by comparison. (A similar punchline was used in the title text of 388: Fuck Grapefruit .) With the plot Randall makes the observation that the danger of a crash is greatly influenced by its speed and highlights the concept of relativity between what we perceive as "fast," normal sports and two different types of racing cars, vs. a much faster vehicle, a rocket during launch. A rocket may appear to ascend slowly (and of course it begins its ascent slowly), but on the way to orbit it ends up moving very fast. But before it reaches the more extreme speed regime it will be far away from the ground (and the casual observer), where there is nothing to compare this speed to as opposed to a race car speeding by a spectator during a race. Apart from the high speed, there is also the altitude to take into account for a rocket launch, and the vast amount of fuel needed to get into orbit, and any sort of catastrophic failure is almost certainly fatal ( Apollo 13 notwithstanding). Racing cars are often involved in crashes, but at that speed it is possible to construct them so even serious crashes may not be fatal. Although rockets are also made as safe as possible, it is a completely different regime of speed and danger , and the risk of something going wrong during a take off is much higher, and it is impossible to prevent a lethal disaster if the launch fails during the ascent. This results in a much higher mortality rate for each crashed rocket (probably 100%) vs. crashed sports/race cars. Rocket launches are compared to "normal sports " (presumably meaning people running approximately 25 km/h, and possibly also polo horses galloping approximately 40 km/h), NASCAR (which reaches speed of 320 km/h), and Formula One (F1), where the fastest race cars go 380 km/h. Although peak speed for an F1 car is higher than NASCAR, the average lap speed is much lower as F1 tracks have slow corners while NASCAR ovals can be negotiated with much less speed variation. It is also arguable whether F1 is more dangerous than NASCAR - there have been fewer fatalities in F1 this millennium, though fewer cars compete and races are of shorter duration. The 2016 Formula one season had 21 races, with each race lasting 1.5~3 hours. The NASCAR season had 36 races, with each race lasting 3~5 hours. A rocket launched to reach the ISS needs to match the speed of the space station which moves at 27,600 km/h. A rocket that needs to escape from Earth needs to reach 40,270 km/h, but so far no humans have escaped. However, the astronauts going to the Moon came close, with Apollo 10 setting the speed record for manned flights with 39,896 km/h. (It was only about 0.4% faster than the next 7 missions that, in contrast to Apollo 10, were supposed to land on the Moon). The lowest of the rocket speeds mentioned above is still more than 70 times as fast as the highest speed for race cars. The title text serves to emphasize the point further, as an astronaut (used to the several G's of acceleration during takeoff and overall much higher speeds) would likely find a NASCAR car moving at ~300 km/h paltry compared to what they're acclimated to and has supposedly aggravated NASCAR drivers by making a point of saying so. And thus this is used to explain why there are no passenger seats in NASCAR cars, to prevent astronauts from joining the drivers for a nice, slow ride. Of the many charts in xkcd this one is notable for containing the fewest sample points of any scatter plots in xkcd. [A two-axis diagram with two double headed arrows centered in the middle of the panel. Each arrow is labeled. There are four large dots in the diagram, three close together in the top left corner and one in the bottom right corner. Each dot is labeled.] [Y axis:] Top: Crashes are safe Bottom: Crashes are dangerous [X axis:] Left: Slow Right: Fast [Dots from top left to bottom right:] Normal sports NASCAR Formula One Rocket launches

Home Itch Remedies

Home Itch Remedies

https://www.xkcd.com/1702

https://www.explainxkcd.com/wiki/index.php/1702:_Home_Itch_Remedies

[Megan and Cueball stand together while Megan loudly scratches her itches and Cueball holds a hand up.] Megan: Argh, bug bites are the worst . I shouldn't scratch, but... so itchy. Cueball: Oh, you know what's great for that? Scratch scratch [Zoom-in to Megan's head.] Megan: No, don't tell me. Everyone always has weird home remedies that never work. I just want sympathy. Cueball (off-panel): No, this one isn't weird, I promise. It really helps! [A frame less panel with a zoom-out back to Megan and Cueball. Megan is still scratching loudly and Cueball still holds his hand up.] Cueball: First, take a hot shower. Then dip some ice cubes in vinegar and use them to crush one baby aspirin. Then make some tea, and... Scratch scratch [Megan walks past Cueball and away from him while Cueball turns and looks after her.] Cueball: ...then, you need a rare French orchid- Megan: I'm going to try a different home remedy where I complain a lot and scratch until my skin comes off. Cueball: Sounds effective. Megan: It's an old family trick.

Bug bites , such as mosquito bites, are itchy. Home remedies are often ineffective, and in some cases very complicated - think of the number of suggestions on how to cure hiccups. In this case Cueball 's suggestion starts out plausible but rapidly gets increasingly and insanely complicated, involving finding rare French orchids. Megan is not actually interested in trying out a complex home remedy, she really just wants sympathy. The suggested remedy is a mix of many popular home remedies such as: Megan's answer is a sarcastic comment stating that her own family home remedy is to keep scratching until the skin falls off -- which is a natural tendency, although not until the skin literally falls off; hence it is not really a home remedy, just a natural reaction. The title text refers to chiggers or Trombicula alfreddugesi as the worst source for itches; in fact only in the larval stages are these mites parasitic. Chigger can also refer to the chigoe flea or "jigger", Tunga penetrans , a parasitic flea which also causes bad itching, but Randall explicitly mentions the mite Trombicula alfreddugesi . A move to a more northerly region of the world like Iceland might seem to be a perfect cure, because those parasites are only found in warmer southern regions (similarly, since mosquitoes lay their eggs in water, moving to a dry place with no water usable by mosquitoes would be a "cure" for mosquito bites). Unusually, Iceland does not support native mosquitoes, despite similarities to other northern regions which do. One might fallaciously assume it does not support parasites in general — but it does support parasitic insects in other genera, and it has other species of mites. Thus, "move to Iceland" is a weird home remedy that will work if the person wants to prevent chiggers, however it won't work if the person wants to stay away from all parasites. This comic could be seen as a continuation of the title text from 1693: Oxidation , where that is interpreted as Ponytail ineffectively reassuring Megan that her bug bites should not be a concern. [Megan and Cueball stand together while Megan loudly scratches her itches and Cueball holds a hand up.] Megan: Argh, bug bites are the worst . I shouldn't scratch, but... so itchy. Cueball: Oh, you know what's great for that? Scratch scratch [Zoom-in to Megan's head.] Megan: No, don't tell me. Everyone always has weird home remedies that never work. I just want sympathy. Cueball (off-panel): No, this one isn't weird, I promise. It really helps! [A frame less panel with a zoom-out back to Megan and Cueball. Megan is still scratching loudly and Cueball still holds his hand up.] Cueball: First, take a hot shower. Then dip some ice cubes in vinegar and use them to crush one baby aspirin. Then make some tea, and... Scratch scratch [Megan walks past Cueball and away from him while Cueball turns and looks after her.] Cueball: ...then, you need a rare French orchid- Megan: I'm going to try a different home remedy where I complain a lot and scratch until my skin comes off. Cueball: Sounds effective. Megan: It's an old family trick.

Juno

Juno

https://www.xkcd.com/1703

https://www.explainxkcd.com/wiki/index.php/1703:_Juno

[At a NASA press conference Blondie stands behind a lectern with the NASA logo. To the left is Megan and to the right is Cueball, both looking towards Blondie.] Blondie: After traveling 1.7 billion miles, the Juno spacecraft reached Jupiter within one second of its scheduled arrival time. [A person off-panel to the left comments and all three turns towards the speaker.] Off-panel voice: Very impressive! Blondie: Thank you. [All three look straight out as Megan comments on the praise.] Megan: I mean, we were aiming for Saturn. Still, nailed the time. Blondie: Shhhh.

This comic was written in honor of the Juno space probe , which made headlines around the world the day before this comic was posted, when it fired its engines and successfully entered into orbit around the planet Jupiter . It was reported on the day of this comic's release that Juno arrived at its orbit one second off its planned schedule . Since the comic is based on such reports this may explain why this comic was released rather late on the day after Juno's arrival, and also why it was not the subject of the previous comic which was released on the day (fourth of July) when the space probe officially reached Jupiter. This makes it one of several space probe related comics to be released to celebrate the arrival of a space probe to its destination, the previous being 1551: Pluto , which celebrated the arrival of the New Horizon's probe at the dwarf planet Pluto. Speaking at a NASA press conference, Blondie , standing behind a lectern , announces that Juno has arrived at Jupiter within one second of its scheduled arrival. After traveling 1.7 billion miles (2.8 billion km) such precision is very impressive, which is acknowledged by someone from the press. The joke is that one of the NASA engineers, Megan , reveals that they actually intended for Juno to arrive at Saturn , but actually arrived at Jupiter with a timing that was still apparently the same within one second. Given the reaction from the spokesperson, she knew this but it was not supposed to slip out. This is, of course, not true, because if Saturn had been the intended target, Juno would have been off course by 10.25 AU (1 AU is the distance from the Earth to the Sun, or 149597870700 meters) when it arrived at Jupiter. Randall might be making a subtle (or not so subtle) reference to past difficulties NASA has had when converting to metric measurements —in July 2016, Jupiter was 870 million kilometers (540 million miles) from Earth, while Saturn was 850 million miles (1.37 billion km) from Earth (about half the distance traveled by Juno). A similar measurement coincidence was noted in what if? A Mole of Moles . Also, Saturn is a maximum of 1.7 billion kilometers (1.1 billion miles) away from the Earth. For Jupiter, this distance is 968 million km (601 million miles) away. But when traveling between planets, long detours are necessary to reach the goal with a velocity that enables the space craft to go into orbit. So it is just a coincidence that Juno has traveled a distance to get to Jupiter in kilometers that fits with a possible distance to Saturn in miles. The mixup of units mentioned above was directly referenced in 1643: Degrees . The mix-up of Jupiter and Saturn could be a reference to the book and the film 2001: A Space Odyssey that were written simultaneously. In the book solely written by Arthur C. Clarke they go to Saturn. In the film (from 1968), however, they found it impossible to make Saturn's rings well enough to satisfy director (and co-writer) Stanley Kubrick so in the film version, they ended up at Jupiter instead. (Arthur C. Clarke later made the film canonical when he wrote the sequel 2010 , where the plot would only work with Jupiter, mainly because of its size and partly due to its four big moons especially Europa ). It's ambiguous who participates in the title text dialogue. There are multiple interpretations. It should be noted that Juno is mostly linked to Jupiter and not to Saturn (the probe was sent to Jupiter in the real world), which fits best with the "Press speaks first" explanation. In the title text someone from the press asks another question: wasn't the name of the space probe, Juno , a tip off given the relation to Jupiter? The goddess Juno was the wife of Jupiter the chief deity in the Roman mythology . However her father is Saturn so there are relations to both Gods/planets. Her relationship to Jupiter, however, is most likely more common knowledge explaining the naming of the probe. However, instead of mentioning this dual relationship one of the three NASA representatives say that at first they even believed it was for Juneau , the capital of Alaska , showing that the engineers did not have a clue about the objective of the mission. They did wonder why a gravity assist was planned to get there but guessed it was a more efficient method. Given that gravity assist is only relevant for interplanetary missions requiring a flyby of a planet, it would never make sense to use one to get between two destinations on Earth. This is so even though Cape Canaveral Air Force Station in Florida, from where the probe was launched, is about as far away from Juneau as it is possible to get inside the borders of the United States. Maybe it was Cueball who was clueless, in which case he may represent Steve from 1532: New Horizons , now confessing to misdirecting another probe. The mixup of Juno the Goddess and the capital city of Alaska could be a reference to the film Juno where the title character is named after the Goddess as her father is into Roman and Greek mythology (although she calls her Zeus 's wife, Zeus being the equivalent of Jupiter in Greek mythology where Juno would be called Hera ). Later a man asks her " Like the city in Alaska? " to which she simply replies "No!" Scenarios similar to the likely outcome of Juno using its gravity assist (from Earth) to arrive in Juneau (with unchanged orbital energy) have been discussed in what if? Orbital Speed , Hitting a comet , and New Horizons (see also 1532: New Horizons ). In the title text someone, likely a member of the NASA team, asks if the name of the space probe, Juno , wasn't a tip off. In Roman mythology the goddess Juno was the daughter of Saturn (though also the wife of Jupiter ). However, instead of mentioning this, someone (presumably a member of the press) replies that at first they had thought the probe was named for Juneau , the capital of Alaska . They had wondered why NASA wanted to use gravity assist to get there, but had guessed that it must be more efficient. The title text might also be continued discussion amongst the NASA representatives. After being shushed, Megan begins needling the spokeswoman about the huge error NASA made. The spokeswoman then admits to being confused about why the mission was so complicated. Alternatively, the third NASA representative might be Steve , now confessing to misdirecting another probe. In another interpretation, both lines are spoken by members of the audience. The second would seem to be producing science journalism of unusually poor quality. [At a NASA press conference Blondie stands behind a lectern with the NASA logo. To the left is Megan and to the right is Cueball, both looking towards Blondie.] Blondie: After traveling 1.7 billion miles, the Juno spacecraft reached Jupiter within one second of its scheduled arrival time. [A person off-panel to the left comments and all three turns towards the speaker.] Off-panel voice: Very impressive! Blondie: Thank you. [All three look straight out as Megan comments on the praise.] Megan: I mean, we were aiming for Saturn. Still, nailed the time. Blondie: Shhhh.

Gnome Ann

Gnome Ann

https://www.xkcd.com/1704

https://www.explainxkcd.com/wiki/index.php/1704:_Gnome_Ann

The Legend of Gnome Ann [At the beach, between a clock hanging in the air, showing 10 past 10 and the shoreline, Gnome Ann, a woman with curly hair and a black triangular hat, stands with her arms outstretched towards the clock and the sea. For each of the first five panels a text is written within a frame above the drawings.] Time and tide wait for Gnome Ann. [Gnome Ann running in from the left frame with her arms out chases three Cueball like men running from her towards right. The one closest to her looks over his shoulder at her, the next runs forward "normally" and the last in front throws up his arms in the air.] The wicked flee when Gnome Ann pursueth. - Proverbs 28:1 [Gnome Ann takes the groom's place in a wedding, shoving him to the side. The groom, Hairy with a bow tie, falls while throwing his arms out. The bride stands to the left, in full wedding dress, showing no reaction.] What therefore God hath joined together, let Gnome Ann put asunder. - Mark 10:9 [Gnome Ann sits in a yoga position meditating on a big rock in a desolate area with small rocks on the ground around the big rock.] Time ripens all things; Gnome Ann is born wise. - Miguel De Cervantes [The starship Enterprise from Star Trek is seen from behind as it flies to the right, chasing a smaller craft. In this panel the frame with text is shown to emanate from Enterprise with a zig zag arrow pointing to the starship.] Enterprise: Our Mission: To boldly go where Gnome Ann has gone before. [The Witch-king of Angmar, Lord of the Nazgûl, from the Lord of the Rings sits on his knees (below the frame) to the left of Gnome Ann, who is preparing to stab him with a sword pointing at his head. She is also holding her other arm out towards him. The Witch-king has a black cloak covering his head and body with a kind of crown with six small spikes shown around his head and one large spike in front. It also goes down on each side of his head showing a gaping hole instead of a face. In this panel the text is spoken by the two characters.] Witch-king: Fool! No man can kill me. Gnome Ann: I Am Gnome Ann!

This comic presents a series of images depicting a female gnome who is known as "Gnome Ann". The humor derives from the fact that the name "Gnome Ann" is a mondegreen of the phrase "no man". (For clarification, "gnome" is pronounced as in the fantastical creature and not as in the Linux-based Gnome desktop system .) Randall presents the reader with six images (and a title text) captioned with quotations from a wide range of sources, each featuring an instance of the compound noun "no man" being replaced by "Gnome Ann" (and featuring a drawing that reflects this change). There is one proverb, two Biblical quotations, one literary quotation from Cervantes ' Don Quixote , one cinematic reference from the Lord of the Rings (film series) (the line Éowyn said to the Witch-king of Angmar before killing him), one quotation from the opening of a television show ( Star Trek: The Original Series ), and a quotation from a piece of historical rhetoric in the title text. The Legend of Gnome Ann [At the beach, between a clock hanging in the air, showing 10 past 10 and the shoreline, Gnome Ann, a woman with curly hair and a black triangular hat, stands with her arms outstretched towards the clock and the sea. For each of the first five panels a text is written within a frame above the drawings.] Time and tide wait for Gnome Ann. [Gnome Ann running in from the left frame with her arms out chases three Cueball like men running from her towards right. The one closest to her looks over his shoulder at her, the next runs forward "normally" and the last in front throws up his arms in the air.] The wicked flee when Gnome Ann pursueth. - Proverbs 28:1 [Gnome Ann takes the groom's place in a wedding, shoving him to the side. The groom, Hairy with a bow tie, falls while throwing his arms out. The bride stands to the left, in full wedding dress, showing no reaction.] What therefore God hath joined together, let Gnome Ann put asunder. - Mark 10:9 [Gnome Ann sits in a yoga position meditating on a big rock in a desolate area with small rocks on the ground around the big rock.] Time ripens all things; Gnome Ann is born wise. - Miguel De Cervantes [The starship Enterprise from Star Trek is seen from behind as it flies to the right, chasing a smaller craft. In this panel the frame with text is shown to emanate from Enterprise with a zig zag arrow pointing to the starship.] Enterprise: Our Mission: To boldly go where Gnome Ann has gone before. [The Witch-king of Angmar, Lord of the Nazgûl, from the Lord of the Rings sits on his knees (below the frame) to the left of Gnome Ann, who is preparing to stab him with a sword pointing at his head. She is also holding her other arm out towards him. The Witch-king has a black cloak covering his head and body with a kind of crown with six small spikes shown around his head and one large spike in front. It also goes down on each side of his head showing a gaping hole instead of a face. In this panel the text is spoken by the two characters.] Witch-king: Fool! No man can kill me. Gnome Ann: I Am Gnome Ann!

Pokémon Go

Pokémon Go

https://www.xkcd.com/1705

https://www.explainxkcd.com/wiki/index.php/1705:_Pok%C3%A9mon_Go

[Cueball walks in to the frame from the left. On the sidewalk in front of him is a small Pokémon figure looking like a standing turtle with a long squirrel like tail, known as Squirtle. Lines around it indicate that it is moving forth and back (wobbling), and circle lines below indicate that there is light below it. The exact position of the Pokémon and these lines around it change through all four images, but stays almost in the same position.] [Cueball takes out his smart phone and points its camera at the Pokémon while looking at the screen.] [Cueball shakes his smart phone violently up and down indicated with four to five gray drawings of his arm and phone below and above one solid black copy of the hand and phone. There are also two gray lines above and below the outer gray phones to indicate this shaking.] [Cueball has lowered his smart phone and just stands there looking at the wobbling Pokémon.] Cueball: ??? [Caption below the comic:] My hobby: Building plastic Pokémon with subtle underlighting and a gyroscope to make them drift back and forth, then leaving them sitting around to mess with Pokémon Go players.

Pokémon GO is an augmented reality (AR) smartphone game, where players walk around the real world, guided by a virtual map sprinkled with Pokémon , trying to find and capture these creatures from the first to fifth generations (i.e. Pokémon from the first to fifth series of games released), then leveling them up and/or evolving them, and using them in battle, similar to the classic Pokémon games for handheld consoles. These Pokémon are randomly placed around the world in the AR format so that they can only be seen through the phone. Randall is playing a prank on all players happening upon his real Pokémon figures as they are so consumed with this new game that they assume that they are from the game, not realizing that they should not be able to see them before they take out their phones, and then after doing this wondering why their phone is having trouble loading them. Due to the popularity of the Pokémon franchise, after Pokémon GO's release in the United States on July 6, 2016, many fans of the series have been walking around with their smartphones out to capture and battle Pokémon. Some players are so eager to capture rare Pokémon (for example, Vaporeon ) that they will leave their cars amid traffic with the engines running. Randall jokes that he has replicated the AR properties of the Pokémon in the app (that is, when you encounter a Pokémon, it is a small computer-generated sprite placed over your phone's rear camera image that moves about your screen, giving the appearance of a "real" Pokémon in front of you). Randall's real life plastic models of various Pokémon have been constructed so they would seem to fit on a smartphone screen due to perspective, he has embedded a gyroscope in them so they wobble about their base giving them the appearance of basic computer-created movement, and as a final touch he has added a subtle underlighting which is also part of the game, and gives them a slightly computer-generated look compared to the real world around them. These effects combined fool avid Pokémon GO players into taking out their smartphone to capture the Pokémon for their game, when in fact it is just a toy sitting in front of them, and they should have known this as mentioned above. In this comic Randall displays the Pokémon called Squirtle which looks like a little turtle. This comic is part of the My Hobby series . In this case, the hobby is pranking players of Pokémon GO by replicating the appearance of the augmented reality mechanic. In the title text, Randall is still waiting for an update that allows capture of strangers' pets - besides the obvious, playing by the rules of Pokémon only wild (not any with an owner) Pokémon can be caught. However, in the Pokémon Colosseum games, through the use of a specialized device the player steals from the villains, the player can capture other trainers' Pokémon. This is also a callback to an earlier strip wherein Black Hat wishes for a Pokéball that works on strangers' pets (see last entry in 1086: Eyelash Wish Log ). Pokémon Go was again the topic of 2220: Imagine Going Back in Time more than 3 years later. [Cueball walks in to the frame from the left. On the sidewalk in front of him is a small Pokémon figure looking like a standing turtle with a long squirrel like tail, known as Squirtle. Lines around it indicate that it is moving forth and back (wobbling), and circle lines below indicate that there is light below it. The exact position of the Pokémon and these lines around it change through all four images, but stays almost in the same position.] [Cueball takes out his smart phone and points its camera at the Pokémon while looking at the screen.] [Cueball shakes his smart phone violently up and down indicated with four to five gray drawings of his arm and phone below and above one solid black copy of the hand and phone. There are also two gray lines above and below the outer gray phones to indicate this shaking.] [Cueball has lowered his smart phone and just stands there looking at the wobbling Pokémon.] Cueball: ??? [Caption below the comic:] My hobby: Building plastic Pokémon with subtle underlighting and a gyroscope to make them drift back and forth, then leaving them sitting around to mess with Pokémon Go players.

Genetic Testing

Genetic Testing

https://www.xkcd.com/1706

https://www.explainxkcd.com/wiki/index.php/1706:_Genetic_Testing

[Cueball and Megan are talking to each other.] Cueball: I sent a DNA sample to one of those "Trace your ancestry" projects. Megan: How legit are those? Cueball: No idea. I just figured it'd be fun. Six weeks later... [Cueball walks towards Megan with a letter in his hand.] Cueball: Sweet, got my results back. Megan: Ooh, share! Ancestry Report 48% Labrador Retriever 35% Beagle 12% Cocker Spaniel 5% Other [Megan is holding the report.] Megan: I think you sent your sample to the wrong service. Cueball: Just in case, I should probably start avoiding chocolate.

Cueball has sent a DNA sample to a genetic genealogy company. The implied premise of the comic is that Cueball intended to send his own DNA to one of the several companies that analyze human DNA samples and provide a report as to the genetic history of that person - examples include notable/famous ancestors or relatives, ethnic background, risk factors for certain medical conditions, etc. However, the result that Cueball receives is consistent with a report for a dog pedigree test, breaking down the percentage of certain breeds present in a dog's ancestry. Megan suggests that Cueball has sent his sample to the wrong company. Cueball appears to agree in principle, but (seriously or jokingly - it is unclear) indicates that he intends to hedge his bets and avoid chocolate just in case he actually is, in fact, a dog. Dogs are generally susceptible to poisoning from theobromine , a compound found in chocolates which causes seizures and heart failure in dogs (and many other creatures). Basically, if Cueball really is a dog, then eating chocolate could kill him. 82% or 94% of genes (depending on how you measure it) are shared between humans and dogs. National Geographic erroneously reported that only 5% of human DNA is shared with dogs and mice, which may have misled Randall Munroe. This leads to several possible interpretations of the comic: It is possible (as Cueball suggests in the last panel) that he is, in fact, a dog with excellent human impersonation skills, or that he somehow shares DNA with a dog. It is possible that Cueball mistakenly sent a sample of a dog's DNA (perhaps his own) somehow thinking that is the method of testing his own DNA. Perhaps Cueball submitted his own (human) DNA to a dog pedigree company and their method of testing includes a presumption of dog DNA, and therefore was able to produce this result from Cueball's sample. Or perhaps this comic is a suggestion that some DNA test companies are scams that do not even perform DNA tests, but simply send out arbitrary reports that are not based on any testing. The title text refers to the fact that certain dog breeds are more or less susceptible to disease. The diseases he mentions, elbow dysplasia , heartworm , parvo virus and mange are several diseases that can end up killing, disfiguring or disabling dogs, but which humans are generally not susceptible to. As noted above, ancestry DNA test results can inform people about their genetic risk factors for disease, either by specifically investigating your own DNA for those risk factors or, more likely (and less costly) by informing of what risk factors are generally prevalent in your ancestry or others people sharing the same ancestry as you. After this comic was published, it was revealed that a testing service issued reports determining that First Nations ancestry was detected in sample DNA taken from a dog. [Cueball and Megan are talking to each other.] Cueball: I sent a DNA sample to one of those "Trace your ancestry" projects. Megan: How legit are those? Cueball: No idea. I just figured it'd be fun. Six weeks later... [Cueball walks towards Megan with a letter in his hand.] Cueball: Sweet, got my results back. Megan: Ooh, share! Ancestry Report 48% Labrador Retriever 35% Beagle 12% Cocker Spaniel 5% Other [Megan is holding the report.] Megan: I think you sent your sample to the wrong service. Cueball: Just in case, I should probably start avoiding chocolate.

xkcd Phone 4

xkcd Phone 4

https://www.xkcd.com/1707

https://www.explainxkcd.com/wiki/index.php/1707:_xkcd_Phone_4

[An image of a smartphone featuring wings is shown. Clockwise from the top left the labels read:] 18,000 μAh nickel-lithium-iron battery (non-rechargeable) Subwoofer "Dog whistle" Non-porous, washable WebMD partnership: Cough-activated feature reads aloud a random diagnosis for "coughing" Wings Beveled bezel Bezeled bevel Seedless Water resistant down to 30 meters and below 50 Turing-complete Gregorian/Julian calendar switch SpaceX impact protection: When dropped, phone lands on barge Parallel port 12 headphone jacks Onboard cloud New BrightGlo TM display incorporates genetically spliced jellyfish protein (should have used the glowing genes, not the stinging ones) ✓ Certified Software-defined Exposed ductwork Voice interaction: Siri, Cortana, Google Now and Alexa respond simultaneously [Below the phone:] Introducing The xkcd Phone 4 Did you know "4" is "IV" in Roman numerals? ®© ™

This is the fourth entry in the ongoing xkcd Phone series , and once again, the comic plays with many standard tech buzzwords to create a phone that sounds impressive but would actually be very impractical. The previous comic in the series 1549: xkcd Phone 3 was released just over a year before this one and the next 1809: xkcd Phone 5 was released almost 8 months later. From the top-left, going clockwise: [An image of a smartphone featuring wings is shown. Clockwise from the top left the labels read:] 18,000 μAh nickel-lithium-iron battery (non-rechargeable) Subwoofer "Dog whistle" Non-porous, washable WebMD partnership: Cough-activated feature reads aloud a random diagnosis for "coughing" Wings Beveled bezel Bezeled bevel Seedless Water resistant down to 30 meters and below 50 Turing-complete Gregorian/Julian calendar switch SpaceX impact protection: When dropped, phone lands on barge Parallel port 12 headphone jacks Onboard cloud New BrightGlo TM display incorporates genetically spliced jellyfish protein (should have used the glowing genes, not the stinging ones) ✓ Certified Software-defined Exposed ductwork Voice interaction: Siri, Cortana, Google Now and Alexa respond simultaneously [Below the phone:] Introducing The xkcd Phone 4 Did you know "4" is "IV" in Roman numerals? ®© ™

Dehydration

Dehydration

https://www.xkcd.com/1708

https://www.explainxkcd.com/wiki/index.php/1708:_Dehydration

[White Hat and Cueball standing together.] White Hat: Many people are mildly dehydrated. And don't realize it. You should drink at least six glasses of water per day. [A voice comes from off-panel to the left as Ponytail enters from the left and Black Hat from the right in this frameless panel.] Off-panel voice: No, eight glasses! Ponytail: I heard ten. Black Hat: You need to drink at least five glasses of water per minute. [Megan is standing to the left holding a book or a thick binder along her side while holding up a finger with the other hand. A question comes from off-panel to the right. Above her a caption is written in a small frame that breaks the top of this panel's frame:] Later: Megan: Okay, I just read through every study I could find to try to figure out whether low-grade dehydration is even a real thing. Off-panel voice: What did you learn? [Megan looking downwards, has two starbursts a circles and two dots above her head signifying dizziness. Cueball stands to the right as another voice comes from off-panel to the right.] Megan: If you spend all day doing research and forget to eat or drink, you start to feel pretty bad. Off-panel voice: I'll get some water. Megan: But how many glas - Whoa, feeling dizzy. Cueball: Maybe you should just drink straight from the tap.

This comic plays on the idea that there is little to no consensus in the scientific community with regard to the amount of water a person should drink per day. In the first panel White Hat presents Cueball with an innocent and sensible suggestion (although controversial) that people should drink six or more glasses of water per day. In the second panel, more characters join the discussion, an off-panel voice claims the most common misconception of eight glasses a day, a number which is not supported by scientific research. Ponytail again goes two higher with ten highlighting the existence of a wide range of so-called 'optimum' liquid consumption 'rule-of-thumb'. Implied here is the variety of health-related books, articles, blogs or other literature published that self-proclaims an optimum drinking formula. The first sign of absurdity also arises here in the second panel when Black Hat posits that we need 5 glasses of water every minute. This equates to 7200 glasses of water a day, and using an often cited " standard definition of a glass " being equal to 8 oz (236 ml), Black Hat is suggesting that we should each drink 1.7 cubic meters (1700 liters) of water a day, curing dehydration but also causing water intoxication . This is a typical Black Hat kind of statement that he uses to further emphasize the absurdity of the problem at hand. Some time later Megan , despite having read through all studies on dehydration (or low-grade dehydration in particular), still has not come to a solid conclusion. She becomes dizzy, admitting that she's been so focused on her work, she has ironically forgotten to eat or drink . Her personal experience with dehydration prompts someone off-panel to get some water, but since she couldn't find any consensus in her research, she asks how many glasses they should bring her. Presumably to avoid the question of "how many glasses" entirely, Cueball finally suggests that she should drink straight from the tap, a (tenuously) sincere suggestion seeing her dehydration and following the good advice to drink when you are thirsty until that state has been absolved. In the title text of 1744: Metabolism , released less than 3 months after this one, Cueball mentions how he starts to feel bad if he refrains from drinking, just like Megan here. The title text contains a mix-up between two often stated intervals; drinking eight glasses of water per day (which makes no sense, see above) and changing the engine oil every 3000 miles (almost 5000 km) which may be a good rule, but not a necessity. Obviously it's impossible to drink 3000 glasses of water, and changing the oil every eight miles (about 13 km) would make driving a car very impractical. The subject of this comic has been graphed in 715: Numbers and mentioned in the what if? Soda Planet : Later, in the what if? Faucet Power , Randall comments on the preference for even numbers in the graph, and writes: How many glasses is "some water" remains an open question. Beret Guy and Megan are participants of a thought experiment concerning glasses of water and vacuum in the what if? Glass Half Empty . And the six glasses of water that this comic began with is also mentioned later in 1853: Once Per Day . This is a rare example of a normal xkcd comic of few panels manages to use five of the seven major characters who actually interact. It is the first comic where Black Hat has spoken (or directly interacted) with White Hat. Until this comic, they have only appeared together in complicated/large drawings where there is no interaction between the two. The only other time this has happened is in 1881: Drone Training . [White Hat and Cueball standing together.] White Hat: Many people are mildly dehydrated. And don't realize it. You should drink at least six glasses of water per day. [A voice comes from off-panel to the left as Ponytail enters from the left and Black Hat from the right in this frameless panel.] Off-panel voice: No, eight glasses! Ponytail: I heard ten. Black Hat: You need to drink at least five glasses of water per minute. [Megan is standing to the left holding a book or a thick binder along her side while holding up a finger with the other hand. A question comes from off-panel to the right. Above her a caption is written in a small frame that breaks the top of this panel's frame:] Later: Megan: Okay, I just read through every study I could find to try to figure out whether low-grade dehydration is even a real thing. Off-panel voice: What did you learn? [Megan looking downwards, has two starbursts a circles and two dots above her head signifying dizziness. Cueball stands to the right as another voice comes from off-panel to the right.] Megan: If you spend all day doing research and forget to eat or drink, you start to feel pretty bad. Off-panel voice: I'll get some water. Megan: But how many glas - Whoa, feeling dizzy. Cueball: Maybe you should just drink straight from the tap.

Inflection

Inflection

https://www.xkcd.com/1709

https://www.explainxkcd.com/wiki/index.php/1709:_Inflection

[Cueball and Megan, holding a hand up, are seen walking together from afar in silhouette.] Megan: Inflected languages change words to add meaning, like "-s" for plurals or "-ed" for past tense. Megan: Alphabets—where symbols stand for sound instead of words—work well for them, since you can show the changes through spelling. [Zoom in on the two as Megan turns her head back towards Cueball and spreads her arms out.] Megan: Our language family is inflected, but the English branch has lost most of its inflection over the millennia. It's why we don't have all those Latin conjugations. [Cueball speaks as they walk on and Megan replies with three orange-yellow emoji: Thumbs Up Sign pointing right, Clapping Hands Sign pointing up left with two times three small lines to indicate the clapping and Smiling Face With Blushing (red) Cheeks and Smiling Eyes. Below given the closest match possible as of the release of the comic.] Cueball: Could that mean English writing is ripe to become more pictographic? Megan: 👍 👏 😊 In the table below is a sample of a modern verb conjugation in English. In all of these conjugations, the only inflections on the main verb "walk" are "-s", "-ed", and "-ing". The highly irregular helper verbs, "be" and "have", have somewhat more interesting inflections. And although this table shows only the third person, the first and second person would only introduce the helper verb "am" (as in "I am walking"); similarly, the table shows only the indicative mood, but the subjunctive and imperative moods would not introduce any additional words, and the conditional mood would only introduce the helper verb "would" (an inflection of the irregular helper verb "will") without any additional inflections on the main verb "walk". If instead we made this table in Spanish (for example), then there would be many more inflections on the main verb (12 in the third-person indicative alone, 45 including all persons and moods, if I didn't miscount).

While walking, Megan tells Cueball that in inflected languages — such as German — changes in the spelling of a word changes its meaning, in a predictable way. Megan exemplifies this with how plural forms of nouns are created by sticking an "s" at the end, and past tense of a verb is done by the suffix "ed". Megan then explains that this works well in languages which build on alphabets . She continues to explain that their language family belongs to those that are inflected, but the English branch is becoming less inflected than it used to be. Specifically this explains why English does not have so many Latin conjugations . A conjugation is a pattern of inflections, describing how a particular group of verbs is altered from its root form to represent different grammatical cases. Only verbs have conjugations (are conjugated ), nouns, pronouns, and adjectives are described by declensions (and are declined ). All inflected languages can be described by conjugations and declensions, although Latin is one of the most commonly cited, perhaps because Latin grammar was taught for centuries by monotonous rote learning of the conjugations and declensions. A typical Latin conjugation would be the verb amare , to love. (The English singular uses archaic forms to highlight the number and person.) A complete conjugation includes all tenses (Present, Imperfect, Future, ...), both voices (Active & Passive), and all moods (Indicative, Imperative, Subjunctive, ...). Other parts of speech — infinitives, participles, gerunds, and so forth — are needed to completely define the verb, but are not usually considered to be part of the conjugation. Cueball then asks Could that mean that English writing might be ripe to become more pictographic? Instead of using traditional words, Megan replies with three emojis "Thumbs up" (like), "Applause", and a smiley — thus showing a pictographic version of the writing which has become more popular in the last years. Emoji has become a recurring theme on xkcd. The writing systems of many languages have both pictographic and ideographic origins. "Pictographic" means that they are pictures of some thing that will remind the reader of either the pronunciation or the meaning of the word. The letter "A", for example, originated from a word meaning "ox", but was meant to remind readers of the glottal stop (it wasn't until the Ancient Greeks, who didn't have the glottal stop as a distinct phoneme, got a hold of the Phoenician version that it was transferred to the vowel(s) it is today). "Ideographic" means that they are designed, through pictures, to illustrate some idea. An example would be a "No Smoking" sign, where a red circle with a diagonal line is an abstract representation of "no". In fact, the three emojis used in the third panel of this cartoon are all ideographic, not pictographic, under this definition. "Thumbs up" (like), "Applause", and the smiley, are all emojis that remind us of a concept of approval. Egyptian hieroglyphics contain many pictorial elements, some of which are pictographic in the sense that they are meant to represent the thing that they picture, but many are more abstract (ideographic) or are used for their phonetic value (as "A" was used in early alphabetic systems). Similarly, in the Chinese character writing system, many of the elements have pictographic or ideographic origins; but they are often, and even usually combined in ways that are phonetic and not related to the pictures that were the origins of the characters. Early modern English (think Shakespeare or the KJV Bible) used more forms for the tenses than we do today, which can help illustrate the trend away from inflected forms. In contrast, verbs in English today are often conjugated with auxiliary verbs. See below for details on modern verb conjugation in English . The title text points out that some intentional misspelling are used in Internet slang to alter the meaning of a word: "what" becomes " wat " to express confusion, disgust or disbelief. The title text also uses typographical variation to emphasize the word MORE by using all capital letters. Such emphasis is difficult to show with inflected language alone. This comic is referenced at 4500 BCE in huge chart of 1732: Earth Temperature Timeline . According to that comic it was at that time inflection was invented but just to tease future students so they have to remember a zillion verb endings . [Cueball and Megan, holding a hand up, are seen walking together from afar in silhouette.] Megan: Inflected languages change words to add meaning, like "-s" for plurals or "-ed" for past tense. Megan: Alphabets—where symbols stand for sound instead of words—work well for them, since you can show the changes through spelling. [Zoom in on the two as Megan turns her head back towards Cueball and spreads her arms out.] Megan: Our language family is inflected, but the English branch has lost most of its inflection over the millennia. It's why we don't have all those Latin conjugations. [Cueball speaks as they walk on and Megan replies with three orange-yellow emoji: Thumbs Up Sign pointing right, Clapping Hands Sign pointing up left with two times three small lines to indicate the clapping and Smiling Face With Blushing (red) Cheeks and Smiling Eyes. Below given the closest match possible as of the release of the comic.] Cueball: Could that mean English writing is ripe to become more pictographic? Megan: 👍 👏 😊 In the table below is a sample of a modern verb conjugation in English. In all of these conjugations, the only inflections on the main verb "walk" are "-s", "-ed", and "-ing". The highly irregular helper verbs, "be" and "have", have somewhat more interesting inflections. And although this table shows only the third person, the first and second person would only introduce the helper verb "am" (as in "I am walking"); similarly, the table shows only the indicative mood, but the subjunctive and imperative moods would not introduce any additional words, and the conditional mood would only introduce the helper verb "would" (an inflection of the irregular helper verb "will") without any additional inflections on the main verb "walk". If instead we made this table in Spanish (for example), then there would be many more inflections on the main verb (12 in the third-person indicative alone, 45 including all persons and moods, if I didn't miscount).

Walking Into Things

Walking Into Things

https://www.xkcd.com/1710

https://www.explainxkcd.com/wiki/index.php/1710:_Walking_Into_Things

[Meagan and Cueball, holding a smartphone in his hand, walk through a landscape with patches of grass. They are just passing behind a stump of a tree, a small bush is in front of them and there are two rocks on the ground which extends to rolling hills in the distance under a clear sky with three small white clouds to the right and two seagulls drawn as lying down 3 to the left with four more birds further left and much further away.] Cueball: My life is basically a big controlled trial of whether I'm more likely to walk into something while looking at a book, my phone, or the sky. [Zoom in to Megan and Cueball while they're still walking, no background is shown. Beat panel while she ponders his statement.] [Megan and Cueball still walking.] Megan: The weird thing is that the rate for the control group is so high. Cueball: Walking is hard, okay? The second word in the first panel looks like "UFE", but it's actually "LIFE" with bad 1015: Kerning . At the time the comic was released, Pokémon Go has been gaining popularity, with many people raising concerns about the dangers of walking around while staring at a phone screen. (See 1705: Pokémon Go released two weeks before this).

Cueball comments on the rate of his walking into things while distracted by various stimuli, comparing it to a controlled study where the aim is to research whether he is most likely to bump into something while looking at a book, at his phone, or staring at the sky (something Randall does a lot with his interests in astronomy, optical phenomena, weather phenomena and kites). Megan replies that if this is the case, the rate of the "control group" colliding with things is also weirdly high. In Cueball's metaphor, the "control group" would be his walking around without being distracted, so you would expect him not to collide with anything when able to give his full attention to where he's going. Thus, Megan is implying that Cueball is simply clumsy or easily distracted by other events or his own thoughts, and that his walking into things has little to do with whether he's looking at his phone, in a book or at the sky. Cueball responds defensively, saying that "walking [without bumping into anything] is hard, okay?" Walking actually is a difficult task, as can be observed when trying to teach a robot how to walk, or the time it takes for children to learn it and the way that a baby's first steps are celebrated as an achievement and a milestone in their development. In the title text, Randall remarks that his childhood spent walking around with his nose in a book has prepared him "unexpectedly well" for today's world. Years ago, walking around while staring at something in your hands — such as a book — was considered odd, antisocial and dangerous, and was mostly the province of bookworms and nerds. Yet now, it's commonplace for people to walk around staring at their phones. This, ironically, makes those "antisocial" people who grew up used to walking around while reading the best-adapted to navigating while using a smartphone. [Meagan and Cueball, holding a smartphone in his hand, walk through a landscape with patches of grass. They are just passing behind a stump of a tree, a small bush is in front of them and there are two rocks on the ground which extends to rolling hills in the distance under a clear sky with three small white clouds to the right and two seagulls drawn as lying down 3 to the left with four more birds further left and much further away.] Cueball: My life is basically a big controlled trial of whether I'm more likely to walk into something while looking at a book, my phone, or the sky. [Zoom in to Megan and Cueball while they're still walking, no background is shown. Beat panel while she ponders his statement.] [Megan and Cueball still walking.] Megan: The weird thing is that the rate for the control group is so high. Cueball: Walking is hard, okay? The second word in the first panel looks like "UFE", but it's actually "LIFE" with bad 1015: Kerning . At the time the comic was released, Pokémon Go has been gaining popularity, with many people raising concerns about the dangers of walking around while staring at a phone screen. (See 1705: Pokémon Go released two weeks before this).

Snapchat

Snapchat

https://www.xkcd.com/1711

https://www.explainxkcd.com/wiki/index.php/1711:_Snapchat

[Cueball and Megan standing together. He holds a smartphone in his left hand and looks at it.] Cueball: Oh, the Pulitzer Prize for Snapchat was just awarded. Megan: Yeah. Megan: I hear the photo was really good. Cueball: Aw, maaaan ...

Snapchat is a photo-sending app that allows the receiving user to view the photo (known as a "snap") only within 24 hours of its posting, and for only 10 seconds before it is deleted. The Pulitzer Prize is famously awarded for exceptional journalism and photojournalism (there are many categories; see here ). Cueball reads that the Snapchat Pulitzer Prize has just been awarded but then, when Megan states that she heard the picture was really good, Cueball becomes disappointed because he realises he has already missed out on the chance to see the prize winning entry due to the temporary nature of Snapchat. Note that Megan also missed the opportunity to see the snap. A given snap can be sent to a semi-public "Story" and the user decides how long any user can see the snap in a range from 1-10 s . In principle, any specific snap is only accessible for 24 hours even if it is a story. A committee of users could have more than 10 seconds to access the snap, by viewing in sequence. Given the time it might take for a committee to decide which snap wins the prize, it is realistic that Cueball learns about the winner after the 24 hours is up; Thus even a user following the outcome might not be able to see the winning entry after that time. In practice it is possible to circumvent the Snapchat rule and take a screen shot or in other ways save the content of the snap. In the case of a Pulitzer Prize winning photo, someone would probably have saved it, if it was in real life. On the other hand, the only way for the photo to be recognised as a snap, eligible to win the prize, would be if no one could see it for more than 10 seconds. So one of the possible rules might be that any picture which was saved would not be able to win the prize. The title text extends this ephemeral nature of Snapchat's content to the prize awarded for it: The other Pulitzer prizes are announced annually in April and awarded in May (except for 2016, the centennial year, when an awards dinner will be held in October). The Snapchat Pulitzer Prize alone must be awarded as quickly as possible after the winner has been decided, before the prize committee forgets what the winning picture looked like. This of course underlines how silly this idea is, because only images seen during the assembly of the prize committee can be seen and remembered, and it is not possible to arrange this based on any knowledge of when a Pulitzer Prize "worthy" snap will be released. Randall could be making fun of Snapchat (see the title), and the idea that you cannot save the images for later; As mentioned regarding screenshots, it is actually very easy to save pictures from Snapchat - to many a user's regret after having sent something very personal, such as naked pictures of themselves. The comic could also be seen as mocking the Pulitzer Prize for having too broad a spectrum of categories. Alongside the (photo)journalistic and prose awards, the Pulitzers also honor a variety of artistic pursuits, including Poetry, Drama and Music. The new medium of Snapchat is certainly a hybrid form of art and information/opinion dispersal, both at its best and at its worst, but it is too ephemeral for awarding prizes to be logistically possible even if it were taken seriously enough for someone to want to award them. The very next comic, 1712: Politifact , features an organization which was awarded the Pulitzer Prize for National Reporting in 2009. [Cueball and Megan standing together. He holds a smartphone in his left hand and looks at it.] Cueball: Oh, the Pulitzer Prize for Snapchat was just awarded. Megan: Yeah. Megan: I hear the photo was really good. Cueball: Aw, maaaan ...

Politifact

Politifact

https://www.xkcd.com/1712

https://www.explainxkcd.com/wiki/index.php/1712:_Politifact

[Megan with messy morning hair is walking right and rubs her eyes.] Megan: I did not sleep well last night. [A woman with hair like Megan (but a bit longer) wearing a white hat with brim and a small white card attached to the hat's belt (like a press pass) crawls up on the pane of an open window. She begins all her sentences with the word PolitiFact. When she says this it is written in the color and style of the PolitiFact.com logo with blue Politi and red Fact . Megan has just walked past the window and has turned to look at the woman. She is still holding one hand up and her hair is still messy.] PolitiFact: Politi Fact says mostly true! Megan: Oh no... [In a frame-less panel Cueball is walking right, while Megan, arms stretched out and hair flowing out behind her, runs by him chasing PolitiFact who is running with a hand up to hold her hat in place, hair also flowing out behind her.] Cueball: Not again. Get out of here, PolitiFact! Megan: I swear I locked that window. PolitiFact: Politi Fact says: False! [Cueball and Megan, looking downwards, are standing at the foot of a well made bed with two pillows, and the bedsheets drawn tight. PolitiFact's voice emanates from a starburst at the edge of the shadow under the bed.] Cueball: You can't stay under there forever. PolitiFact (voice from under bed): Politi Fact says: False! Megan: Nobody likes you, Politifact. PolitiFact (voice from under bed): Politi Fact says: Mostly true!

The website PolitiFact.com rates political claims based on how true they are. The rulings from the Truth-O-Meter™ at PolitiFact are: This comic presents a woman wearing a white hat with a press pass in the hat's band. She is calling herself "PolitiFact" - either pretending to come from PolitiFact.com or she is representing a personification of the website itself. She is obviously annoying Megan and Cueball by first breaking and entering and then rating everything they say on the Truth-O-Meter. (She is using the official logo of PolitiFact as her name, and since they write their name PolitiFact her name should also be written like this, even though Randall has named the comic Politifact with all lower case letters and also uses it like this in the title text.) When Megan, apparently just having gotten out of bed, says she had trouble sleeping, the PolitiFact.com woman (henceforth simply PolitiFact) appears at an open window and observes that Megan is telling the truth with the rating of " Mostly True! " (So according to PolitiFact she did not sleep well most of the night, but may have slept OK for some parts of the night.) Megan appears distressed, which is not improved when PolitiFact enters their house through the window. Megan gives chase to PolitiFact, passing by Cueball, whose comment Not again makes it clear that this is not the first time PolitiFact has annoyed them in this way. Megan swears that she had locked the window, though PolitiFact gives that claim the rating of " False! " as PolitiFact herself demonstrated. Although entering someone's house against their wishes is illegal, regardless of how entry is achieved, Megan's failure to secure the window means that PolitiFact cannot be charged guilty of breaking and entering - and, more pressingly, has made it easier for PolitiFact to annoy them. Cueball asks her to leave as Megan chases her through the house. After the chase, PolitiFact ends up hiding under the couple's bed; Cueball's claim that PolitiFact "can't stay under there forever" is promptly rated " False ". Megan's remark, however, that no one likes PolitiFact, is rated " Mostly True! " This exchange is likely metaphorical just as much as it is literal — Randall's PolitiFact acknowledges that what she does annoys people, but she keeps on doing it anyway. As for metaphors, Megan is likely commenting on the popularity of the website, which Randall's PolitiFact is no less correct about. People become very defensive when claims they make in political discussions are debunked by PolitiFact.com. There is a phenomenon where the people most influenced by an erroneous claim are the least likely to believe a fact checker. For example, The Washington Post shut down their internet rumor fact checker because, "institutional distrust is so high right now, and cognitive bias so strong always, that the people who fall for hoax news stories are frequently only interested in consuming information that conforms with their views — even when it's demonstrably fake." Simply put, people like the idea of a fact checker until they disagree with it. PolitiFact.com has been accused of being both liberally biased and conservatively biased at various times and has angered politicians on both sides of the aisle. The summary statistic "rulings" are especially troublesome; often the critics will agree that the information presented by the fact check is correct, and may agree that all relevant information has been included, but will disagree as to the importance of context omitted by the original speaker or the interpretation of ambiguous language. The title text makes a play on PolitiFact.com's most untrue rating, "Pants on Fire!" - a reference to the childhood accusation " Liar, liar, pants on fire! " In the title text either Cueball or Megan says to the other that they have lit the smoke bomb and rolled it under the bed near PolitiFact (seems they have discussed this first). When it goes off it apparently manages to ignite PolitiFact's pants - thus, PolitiFact's pants are literally on fire and she yells "PANTS ON FIRE!". Cueball has thrown smoke bombs before while in a relation with Megan, see 486: I am Not a Ninja , so it would be likely he had a smoke bomb on his person for immediate use. Alternatively, either Cueball or Megan just says this as a threat (they could even roll a non-bomb object under the bed and maybe they have talked out loud about the idea of using such a bomb before) and they could try to make the loud fwooosh sound themselves to simulate that the bomb going off. Then they would be telling an outright lie that would be rated as "Pants on Fire!". The fact that the fwooosh is located outside of the "quotation marks", is no indication as the sound is not part of the quote. Also the fact that "PANTS ON FIRE" is yelled, rather than calmly delivered in the fashion of her other judgments, is not necessarily any indication that this is not the case, since a threat that is so blatantly a lie as to warrant such a rating should be proclaimed out loud. It is also possible that PolitiFact's rating is a meta check of the title text itself ; because the scenario described is not illustrated as is the rest of the comic, it has not happened, and thus is blatantly false. It may be a coincidence, but PolitiFact.com was awarded the Pulitzer Prize for National Reporting in 2009 for work done in their first full year of work (after it was started in August 2007), and this comic was released right after 1711: Snapchat , which hinges on the existence of little-known Pulitzer Prize categories. PolitiFact was later referenced indirectly with a fact check in 1790: Sad which is rated mostly false , and directly in the title text of 2129: 1921 Fact Checker , about, well... fact checking. [Megan with messy morning hair is walking right and rubs her eyes.] Megan: I did not sleep well last night. [A woman with hair like Megan (but a bit longer) wearing a white hat with brim and a small white card attached to the hat's belt (like a press pass) crawls up on the pane of an open window. She begins all her sentences with the word PolitiFact. When she says this it is written in the color and style of the PolitiFact.com logo with blue Politi and red Fact . Megan has just walked past the window and has turned to look at the woman. She is still holding one hand up and her hair is still messy.] PolitiFact: Politi Fact says mostly true! Megan: Oh no... [In a frame-less panel Cueball is walking right, while Megan, arms stretched out and hair flowing out behind her, runs by him chasing PolitiFact who is running with a hand up to hold her hat in place, hair also flowing out behind her.] Cueball: Not again. Get out of here, PolitiFact! Megan: I swear I locked that window. PolitiFact: Politi Fact says: False! [Cueball and Megan, looking downwards, are standing at the foot of a well made bed with two pillows, and the bedsheets drawn tight. PolitiFact's voice emanates from a starburst at the edge of the shadow under the bed.] Cueball: You can't stay under there forever. PolitiFact (voice from under bed): Politi Fact says: False! Megan: Nobody likes you, Politifact. PolitiFact (voice from under bed): Politi Fact says: Mostly true!

50 ccs

50 ccs

https://www.xkcd.com/1713

https://www.explainxkcd.com/wiki/index.php/1713:_50_ccs

[Ponytail in a doctor's coat, walks right while reading from a clipboard, passing Cueball walking the other way while she talks to Megan walking in front of her.] Ponytail: Nurse, bring me 50 ccs! Ponytail: I need to write "hiccup vaccine" 25 times!

This comic presents a busy day in the clinic for doctor Ponytail , who orders 50 ccs from a nurse (probably Megan who walks in front of her rather than Cueball walking away behind her), all the while everyone is hurrying along the hall. This could be a typical scenario in a busy hospital. However the pun is that the 50 ccs are not medicine but should be used to write "hiccup vaccine" 25 times. In medicine, "cc" usually means " cubic centimeter ", and is often called that by medical personnel. A cubic centimeter is equal to 1 ml (milliliter), so "50 ccs" usually means 50 ml of a certain medicine. In this case however, the doctor has not told the nurse to bring 50 ccs of any given medicine; instead, she needs to write "hi cc up va cc ine" 25 times, with both words containing the letter combination "cc", so she needs to write that combination 50 times. That is the joke, that the 50 ccs literally means the two-lettered 'cc' fifty times. There's no conventional vaccine against hiccups . However, performing tasks meant to distract one's self is a method to stop hiccups. Therefore the act of writing "hiccup vaccine" 25 times would itself comprise one more of those hiccup cures that never seems to work. What these techniques all rely on is that they all force one to hold one's breath, thus resetting the diaphragm from its out of sync spasms. But if Ponytail has discovered a vaccine that does somehow cure or prevent hiccups, then this unexpected result is worth reporting in medical journals and seeking grants for further study. Thus, wanting to write about it 25 times is understandable! The title text text refers to a fictional event with four words containing "cc" (ra cc oon, a cc ident, a cc ordion, ba cc hanalia), which means she needs to write "cc" 100 times. Referring to the 50 ccs from above, this would be a double dosage. Although the words of the sentence has been chosen based on their cc's the sentence is quite interesting in itself: So here there is talk of a wine festival with music played on accordions that has had an accident involving raccoons, in addition to the need for vaccine against the hiccups. A similar doctor Ponytail is shown in 883: Pain Rating also along with Cueball and Megan and just with Megan in 996: Making Things Difficult . [Ponytail in a doctor's coat, walks right while reading from a clipboard, passing Cueball walking the other way while she talks to Megan walking in front of her.] Ponytail: Nurse, bring me 50 ccs! Ponytail: I need to write "hiccup vaccine" 25 times!

Volcano Types

Volcano Types

https://www.xkcd.com/1714

https://www.explainxkcd.com/wiki/index.php/1714:_Volcano_Types

[Twelve drawings in four rows of different "volcano" types, the first four real, and some not even volcanoes of any sort, real or fake. Below each panel is a caption with the name of the drawn volcano. Some of the volcanoes have labels or sound written inside the panel. Each of the volcanoes has a baseline for the ground going straight a short distance over the bottom of each panel. All 11 volcanoes lie on top of this line, but some show the inside of the volcano going further into the ground.] [Standard cone shaped volcano, with straight sides sloping up to a triangular shape, but with the tip of the cone cut off to form the central jagged edged crater. White smoke rises straight up and then drifts to the left forming three separate clouds.] Cinder Cone [Flat rounded shaped volcano, as a part of a circle. There is not a real crater visible but from the center a thin plume of smoke rises up, drift drifts to the left and forms a small white cloud.] Shield Volcano [This is the largest volcano. The tip of this volcano is similar to the first volcano, but with more uneven slopes and a bit smaller. The tip is clearly separated from the bottom section by a thin jagged line, and below the sides of the volcano decreases their slope, so they are less steep than the tip. Black smoke rises straight up from the crater and then drifts to the left in four thin lines.] Stratovolcano [A wide volcano spans the entire panel, with a large central crater, with a bottom baseline far above the ground level. Just left of the middle of this crater is a standard smaller volcano cone, very similar to the shape of the tip in the previous panel. Even the smoke from this cones small crater is similar to the previous panels.] Somma Volcano [The central part of this volcano is the same shape as the previous panel. This could be a zoom out, revealing that the large crater, is at the center on an even larger crater, which again is at the center of a crater that spans the panel. A plume of black smoke rises from the centeral cones crater, and drifts left as five white clouds.] Metasomma Volcano [A perfect cone-shape, triangular and steep, with checkered ice cone waffle texture, even with a line indicating where the waffle has been a folded. It looks like a road up the volcano. Black smoke drift up from the sharp tip, no crater, and drifts left forming a small cloud separated from the rest of the smoke lines.] Waffle Cone [Standard cone as in the first, but zoomed in so it fills the panel from left to right. The volcano's top has been cut much further down leaving a wide crater from which lava is pouring down the sides in large rivers of different width and length. To the left one long river has almost reached the ground. Cueball is running down the left side, and Megan is running after another Cueball with his arms up on the right side. There is a label with an arrow pointing to the lava:] Label: Baking soda and vinegar Science Fair Cone [Standard cone like the previous, but with more jagged sloped and crater. This volcano erupts with a large explosion with fire and smoke coming out in all directions above the crater. A large sound is written above the explosion:] Sound. Doooooot Doot Cone [This is not a volcano, but the inverse, a cone down into the ground, the ground level no above the center of the panel. The slope down into this cone hole is straight, the ground above is more jagged. At the bottom of the hole sits a small animal with six legs and an open mouth piece sticking up out of the hole. Its fat body is hidden under the ground along with its legs.] Antlion [Standard volcano cone like the previous volcano. It erupts and the central part shows how the erupting material comes up from below ground level (below the line at the bottom in which the cone it self stands). The erupting material is white rocks on black background. At the top several rocks is blown out of the crater top. The sides of the volcano is filled with blobs small and large, and stones rolling down the sides. There are two labels, each with two arrows. The first labels arrows points to the side of the volcano, the second labels arrows points to the erupting material inside and outside the volcano:] First label: Lava Second label: Solid rocks Inverse Volcano [Standard cone like the doot cone, with a crater that bends down in the middle. From this crater eight white ghosts with two black eyes are rising, like the smoke, drifting left. The highest ghost is just reaching the edge at the top left of the panel. The lowest ghost is still inside the crater with its wavy lower parts.] Ghost Vent [A standard cone like the doot cone. At the top there is lave over the outer edges, some of it running down the side. The inside of the volcano has been drawn like in the inverse volcano, so it is clear that the magma inside the volcano comes up from below ground level (below the line at the bottom in which the cone it self stands). There are two labels that contradicts the description above. The top label outside the volcano points to the lava with an arrow, and the bottom label inside the volcano points to the magma:] Top label: Magma Bottom label: Lava Pedant's Bane

This comic presents a table of 12 different types of volcano. Split into 3 rows, the first 4 are authentic types of volcano; while the remaining 8 are parodies, one not even trying to represent a volcano but shows a real animal in its inverted trap cone. Volcanoes have featured in many xkcd comics, most prominently in the left part of the world (the Lord of the Rings section) of 1608: Hoverboard . This comic's volcano looks like it could soon turn into a Somma volcano. The title text refers to a famous scene in Star Wars: Episode VI - Return of the Jedi where Jabba the Hutt intends to feed Luke Skywalker to the sarlacc , an underground creature that builds a huge funnel trap similar to that of an antlion. Jabba's distinctive sail barge features prominently in that scene, and when Randall comes upon an antlion he can't help himself starting to build a scale model next to the antlion's inverted cone. Given how small antlions are, this will be very difficult to do, see for instance 878: Model Rail . [Twelve drawings in four rows of different "volcano" types, the first four real, and some not even volcanoes of any sort, real or fake. Below each panel is a caption with the name of the drawn volcano. Some of the volcanoes have labels or sound written inside the panel. Each of the volcanoes has a baseline for the ground going straight a short distance over the bottom of each panel. All 11 volcanoes lie on top of this line, but some show the inside of the volcano going further into the ground.] [Standard cone shaped volcano, with straight sides sloping up to a triangular shape, but with the tip of the cone cut off to form the central jagged edged crater. White smoke rises straight up and then drifts to the left forming three separate clouds.] Cinder Cone [Flat rounded shaped volcano, as a part of a circle. There is not a real crater visible but from the center a thin plume of smoke rises up, drift drifts to the left and forms a small white cloud.] Shield Volcano [This is the largest volcano. The tip of this volcano is similar to the first volcano, but with more uneven slopes and a bit smaller. The tip is clearly separated from the bottom section by a thin jagged line, and below the sides of the volcano decreases their slope, so they are less steep than the tip. Black smoke rises straight up from the crater and then drifts to the left in four thin lines.] Stratovolcano [A wide volcano spans the entire panel, with a large central crater, with a bottom baseline far above the ground level. Just left of the middle of this crater is a standard smaller volcano cone, very similar to the shape of the tip in the previous panel. Even the smoke from this cones small crater is similar to the previous panels.] Somma Volcano [The central part of this volcano is the same shape as the previous panel. This could be a zoom out, revealing that the large crater, is at the center on an even larger crater, which again is at the center of a crater that spans the panel. A plume of black smoke rises from the centeral cones crater, and drifts left as five white clouds.] Metasomma Volcano [A perfect cone-shape, triangular and steep, with checkered ice cone waffle texture, even with a line indicating where the waffle has been a folded. It looks like a road up the volcano. Black smoke drift up from the sharp tip, no crater, and drifts left forming a small cloud separated from the rest of the smoke lines.] Waffle Cone [Standard cone as in the first, but zoomed in so it fills the panel from left to right. The volcano's top has been cut much further down leaving a wide crater from which lava is pouring down the sides in large rivers of different width and length. To the left one long river has almost reached the ground. Cueball is running down the left side, and Megan is running after another Cueball with his arms up on the right side. There is a label with an arrow pointing to the lava:] Label: Baking soda and vinegar Science Fair Cone [Standard cone like the previous, but with more jagged sloped and crater. This volcano erupts with a large explosion with fire and smoke coming out in all directions above the crater. A large sound is written above the explosion:] Sound. Doooooot Doot Cone [This is not a volcano, but the inverse, a cone down into the ground, the ground level no above the center of the panel. The slope down into this cone hole is straight, the ground above is more jagged. At the bottom of the hole sits a small animal with six legs and an open mouth piece sticking up out of the hole. Its fat body is hidden under the ground along with its legs.] Antlion [Standard volcano cone like the previous volcano. It erupts and the central part shows how the erupting material comes up from below ground level (below the line at the bottom in which the cone it self stands). The erupting material is white rocks on black background. At the top several rocks is blown out of the crater top. The sides of the volcano is filled with blobs small and large, and stones rolling down the sides. There are two labels, each with two arrows. The first labels arrows points to the side of the volcano, the second labels arrows points to the erupting material inside and outside the volcano:] First label: Lava Second label: Solid rocks Inverse Volcano [Standard cone like the doot cone, with a crater that bends down in the middle. From this crater eight white ghosts with two black eyes are rising, like the smoke, drifting left. The highest ghost is just reaching the edge at the top left of the panel. The lowest ghost is still inside the crater with its wavy lower parts.] Ghost Vent [A standard cone like the doot cone. At the top there is lave over the outer edges, some of it running down the side. The inside of the volcano has been drawn like in the inverse volcano, so it is clear that the magma inside the volcano comes up from below ground level (below the line at the bottom in which the cone it self stands). There are two labels that contradicts the description above. The top label outside the volcano points to the lava with an arrow, and the bottom label inside the volcano points to the magma:] Top label: Magma Bottom label: Lava Pedant's Bane

Household Tips

Household Tips

https://www.xkcd.com/1715

https://www.explainxkcd.com/wiki/index.php/1715:_Household_Tips

[Cueball is standing outside a bathtub with the shower curtains partly drawn aside hanging outside the tub. The shower head is dripping water as Cueball reaches in turning the closest of the two taps. Below these there is a faucet. There is water on the floor at the bottom of the tub and a pool of water behind Cueball.] Cueball: Hi everyone! I'm back with more household tips. To conserve water, try turning off your shower before you leave home. [Cueball is holding a bucket and pours water out of it to the right. The water still hangs in the air over a small fire with four flames on the floor. A similar fire is behind him to the left, except it seems thre is a burning item in this fire, and a single flame is on the floor between that and Cueball. A smoke detector (off-panel) goes off in the background as indicated with lines and sounds.] Cueball: Sick of changing those smoke detector batteries? Eliminate any fires in your house and the batteries can last for months or years! Smoke detector (off panel): Beep beep beep [A frame-less panel shows a a toilet with the toilet seat up and also the lid has been removed from the cistern at the top. It is hanging in the air above and behind the cistern. There is an X with an arrow pointing towards the cistern and a checkmark with an arrow pointing towards the toilet bowl.] Cueball (off-panel): Tired of clogged toilets? Try leaving the lid on the upper chamber and use only the lower bowl! X ✔ [Cueball holding a hand up is standing next to an open window where the bottom part has been slid almost up to the top.] Fresh air doesn't have to be expensive. Many windows can be slid up to create a temporary hole without the usual cost and cleanup!

This is another one of Randall's Tips , this time with a series of household tips. The comic is a continuation of 1567: Kitchen Tips , which had four kitchen tips and then a household tip in the title text. The comic shows Cueball explaining many things one should already know (and are likely already doing without needing to be told), but telling them like most people usually never do it to comedic effect. Below is a list of the five household tips given: To conserve water, try turning off your shower before leaving home : Implies that the shower would "normally" be on at all times, which would be very wasteful. The what if? article " Faucet Power " illustrates similar wasteful and destructive water use. This may be a reference to the common recommendation that people should unplug appliances when they are not in use, as opposed to simply turning them off, as some devices have a "standby" mode that still uses up a small amount of electricity. Sick of changing those smoke detector batteries? Eliminate any fires in your house and the batteries may last for months or years! : A smoke detector on standby consumes much less power than one constantly ringing, since standing by only requires that a detection circuit (which draws little current) be on and an LED flashes a few times a minute (which also consumes very little power), while a buzzer used to sound the alarm uses much energy by comparison. The sentence implies that some people have their fire alarms beeping at all times due to their ongoing fires, and then stop up to change the batteries when they stop working. It is surreal that Cueball would have fires just around his house and not be remotely worried. Of course, keeping one's house fire-free at (mostly) all times is usually done because of other benefits than just saving on batteries, such as preventing fire and smoke damage to valuable property, infrastructure, and human bodies. [ citation needed ] Tired of clogged toilets? Try leaving the lid on the upper chamber and use only the lower bowl! : The "upper chamber", the toilet's cistern tank, delivers plain water to the lower bowl at speed to flush the latter. As such, the pipes that direct the water down are not wide enough for waste to pass. There is typically a lid on the upper tank, because it isn't intended to be used; however, access is occasionally needed to fix or replace the flushing mechanisms. The lower bowl, as one should be familiar with, is the one intended to receive solid waste or defecation [ citation needed ] and is connected to the plumbing by pipes wide enough for this purpose. Fresh air doesn't have to be expensive. Many windows can be slid up to create a temporary hole without the usual cost and cleanup! : This suggests that the people he appeals to typically smash a window (or a wall) to get fresh air, hence the clean up and expensive replacement of the window, once enough fresh air has been obtained. To make your shoes feel more comfortable, smell better, and last longer, try taking them off before you shower. : People typically remove all their clothing, including and/or especially shoes (except perhaps for some lightweight sandals to protect the feet in public showers), when showering, so while it is certainly true that removing one's shoes before showering will allow them to last longer and stink less (since shoes that have little opportunity to dry produce malodorous molds), this is not in any way a novel idea. [Cueball is standing outside a bathtub with the shower curtains partly drawn aside hanging outside the tub. The shower head is dripping water as Cueball reaches in turning the closest of the two taps. Below these there is a faucet. There is water on the floor at the bottom of the tub and a pool of water behind Cueball.] Cueball: Hi everyone! I'm back with more household tips. To conserve water, try turning off your shower before you leave home. [Cueball is holding a bucket and pours water out of it to the right. The water still hangs in the air over a small fire with four flames on the floor. A similar fire is behind him to the left, except it seems thre is a burning item in this fire, and a single flame is on the floor between that and Cueball. A smoke detector (off-panel) goes off in the background as indicated with lines and sounds.] Cueball: Sick of changing those smoke detector batteries? Eliminate any fires in your house and the batteries can last for months or years! Smoke detector (off panel): Beep beep beep [A frame-less panel shows a a toilet with the toilet seat up and also the lid has been removed from the cistern at the top. It is hanging in the air above and behind the cistern. There is an X with an arrow pointing towards the cistern and a checkmark with an arrow pointing towards the toilet bowl.] Cueball (off-panel): Tired of clogged toilets? Try leaving the lid on the upper chamber and use only the lower bowl! X ✔ [Cueball holding a hand up is standing next to an open window where the bottom part has been slid almost up to the top.] Fresh air doesn't have to be expensive. Many windows can be slid up to create a temporary hole without the usual cost and cleanup!

Time Travel Thesis

Time Travel Thesis

https://www.xkcd.com/1716

https://www.explainxkcd.com/wiki/index.php/1716:_Time_Travel_Thesis

[Cueball is facing Megan, talking to her.] Cueball: I've been reading about time travel. Megan: Cool! I did my thesis on time travel! [Cueball is now gesturing toward Megan. An electrical charge of some sort is shown occurring outside the panel in the bottom right corner behind Megan.] Cueball: Nice! So you know about closed timelike curves? Megan: Yup. Thesis. Cueball: Apparently wormholes can use exotic matter to– Megan: I know. Like I said– Charge: Bzzzt! [Megan has turned away from Cueball to the right. Megan from the future, wearing sunglasses, a headset and a machine strapped to her back has entered the frame from the right where the charge appeared.] Future-Megan: You can skip this conversation. It doesn't turn out to be important. Megan: Oh, thank God. [Cueball is standing alone, the two Megans have left the panel.]

Cueball has apparently been reading about time travel . He tells Megan about this, and Megan excitedly remarks that she did her college thesis on time travel which basically means that she is supposed to know a lot more about time travel than a guy who has just been "reading" about it. Cueball, however, continues to ask her if she knows basic facts about time travel (like closed timelike curves , wormholes and exotic matter ), like he is investigating if he has discovered facets about it that she would have overlooked while writing a thesis about it. Megan keeps trying to say that since she wrote a Time Travel Thesis , (hence the title of the comic), she already knows all of this and much, much more, and she is obviously getting frustrated by Cueball's attempts to impress her with his "knowledge". At this point Megan's future-self arrives with a Bzzzzt , having used time travel to arrive at this exact moment in time. It seem she has continued her research and has successfully managed to make a time machine. The reason she arrives is only to tell her younger self that this conversation with Cueball doesn't go anywhere and isn't important, and so present-Megan can leave and not waste her time anymore. Up till then, Megan was presumably reluctant to break off a conversation on the topic of time travel, since the conversation could potentially have improved, or perhaps because he at least had read about time travel which is a subject she would have a clear interest in since she wrote a thesis on it. But once the conversation began to run off track, it came as a relief to know that she could quit without the risk of missing out on anything important. Also, since Megan took the effort to time travel back to this exact moment, that must mean the conversation was so boring and uneventful she kept regretting having this conversation even far into the future to the point where she remembers it as one of the moments that need to be changed with her acquired time travel abilities. And then she just walks away with her future-self leaving Cueball hanging in the last panel, having invented a completely new way to get out of useless/boring conversations. Alternatively, future-Megan just makes an excuse to haul present-Megan off in order to prevent the latter from disclosing some details of time travel science to Cueball, which could have unintended consequences. However, using very advanced technology, or even violating physics law, for very mundane ends is very common in xkcd, so using time travel to prevent useless conversation is not surprising from Megan. In either case, future-Megan finished this conversation before inventing time travel, and thus knows this conversation's outcome. So by coming back, she now changes her own (and Cueball's) future. Of course the general implications of being able to travel like this are enormous, and the paradoxes arising from such a possibility are endless, the most pressing (at the moment) being the grandfather paradox , where a time traveler creates circumstances that negate their existence (such as killing their own grandfather), in this case, Older Megan going back in time to stop Younger Megan from finishing this conversation, who will eventually become Older Megan but with no reason to go back to tell Younger Megan to stop this boring conversation. It is worth noting, however, that the comic does not inherently cause a paradox: so long as the Megan who didn't finish the conversation stills travels back in time with the knowledge that the conversation needed to be stopped and still saves her younger self from wasting her time, a time loop can be logically sustained. (It is also worth noting that a "Mobius" time loop is also perfectly possible, the grandfather paradox isn't a paradox if quantum entanglement is taken into account - something Megan would no doubt know) It is possible that Randall may have had some conversations like this, where after having spent a lot of time getting nothing out of it himself, would have wished his future self had come back to tell him to just leave the conversation now. In the title text present-Megan asks future-Megan about her futuristic googles and what they are for, presumably assuming they are needed for the time travel (maybe it is the backpack?). People from the future wearing weird clothing, often involving eyewear of some sort is a trope in Science-Fiction. Movies like Back to the Future Part II which tried to predict the fashion of 2015 back in 1989 didn't get it right, so this might be a commentary on those movies. However it turns out it's just some old and broken Google Glass . The only reason future Megan wears these is that she attended a party at the club that had a 2010's night theme. The fact that the Google Glass is broken and from 2010 alludes to Randall believing that the project was a fad that and that it will never pan out, even in the future. Indeed that seems to be the case. It seems generally that Randall is no fan of Google Glass, which was also shown earlier in 1251: Anti-Glass and later again in 1304: Glass Trolling . Google Glass has become a recurring theme in xkcd. This is an indication of how far from the future she has traveled, as Google Glass was first released in the 2010s. It is not clear whether she is wearing Google Glass because it became popular in the 2010s or because it was an esoteric piece of hardware that people would readily associate with the 2010s. Also a 90s party may be thrown today, but not a 2000s party. So it is safe to assume that Megan is at least from the 2030s. Also people attending retro dress-up parties frequently make mistakes and do not dress up exactly in-style, creating some anachronisms, especially if they dress up like they did many years ago. [Cueball is facing Megan, talking to her.] Cueball: I've been reading about time travel. Megan: Cool! I did my thesis on time travel! [Cueball is now gesturing toward Megan. An electrical charge of some sort is shown occurring outside the panel in the bottom right corner behind Megan.] Cueball: Nice! So you know about closed timelike curves? Megan: Yup. Thesis. Cueball: Apparently wormholes can use exotic matter to– Megan: I know. Like I said– Charge: Bzzzt! [Megan has turned away from Cueball to the right. Megan from the future, wearing sunglasses, a headset and a machine strapped to her back has entered the frame from the right where the charge appeared.] Future-Megan: You can skip this conversation. It doesn't turn out to be important. Megan: Oh, thank God. [Cueball is standing alone, the two Megans have left the panel.]

Pyramid Honey

Pyramid Honey

https://www.xkcd.com/1717

https://www.explainxkcd.com/wiki/index.php/1717:_Pyramid_Honey

[Cueball and Megan are talking.] Cueball: Apparently honey has an infinite shelf life. They just found jars of it in the pyramids, still good. Megan: You know, I've heard that, and I don't think it's true. [Black hat enters.] Cueball: Really? Smithsonian magazine confirmed it. Megan: Believe it or not, I think their source is wrong. Black Hat: I believe you. [Megan has turned to Black Hat raising her hands.] Megan: See I read about the archaeologists who- Black Hat: I'm convinced. Gonna go to tell the internet. [Black Hat moved closer to Megan and Cueball.] Megan: Wait, are you sure? Let me explain why I- Black Hat: Don't need it. I've heard enough. [Zoom-in on Black Hat's head.] Black Hat: I've been looking for a weird hill to die on, and all the real ones are too far from my house. Black Hat: So this is mine. I'm now a pyramid honey truther. [Zoom back out. Black Hat starts walking left, pointing a finger up. Cueball and Megan turn to look after him.] Black Hat: Time to start a Facebook group and post a bunch of all-caps comments everywhere. Cueball: This could have gone better. Megan: Oh well.

Bee honey is a food item with natural antimicrobial properties. It can remain unspoiled for a person's entire lifetime, making it practically nonperishable for ordinary consumers. It is frequently claimed that archaeologists have found jars of honey that have been well-preserved for thousands of years in ancient tombs, often those found in Egyptian pyramids , hence the title Pyramid Honey . The claims are generally assertions that may point to other similar assertions as supporting evidence but do not provide specific details, such as the identity of the actual tombs where such jars have been found, or the names of the archaeologists who have affirmed finding such jars. Repeated encounters with the assertion lead some people to claim that honey's shelf life is "infinite", which is a much stronger claim which would not necessarily be supported by the assertion even assuming it is true. In the comic, Cueball tells Megan about an article in Smithsonian Magazine (presumably this one ) that claims honey has an infinite shelf life. The article links to a book that makes the assertion of such findings but does not provide factual support of the findings. Megan thinks the source for this article, and others that covered the subject, is wrong and wants to refute them all. She tells Cueball Believe it or not which Black Hat hears and he immediately states that he believes her, and is convinced without hearing any arguments from Megan. He then decides to begin a Facebook page so he can tell the Internet without giving Megan a chance to explain any further. "A hill to die on" is a phrase from Ernest Hemingway's 1940 novel " For Whom the Bell Tolls ", about an American who volunteers in the 1936-1939 Spanish Civil War to fight fascism , who ends up wounded and alone, about to ambush the enemy to give his comrades a chance to escape; "a weird hill to die on" would thus mean a weird cause, if not a just one, to fight for to the bitter end. This expression is also the subject of 2247: Weird Hill . Black Hat asserts that he needs such a cause because the "real" weird hills are too far from his house, humorously implying he would be equally satisfied with a literal weird hill. Black Hat's actions are clearly premature since he has not heard any evidence to back up the claim and does not understand the nuances of Megan's position. Cueball states that it could have gone better, whereas Megan seems to be resigned to it, perhaps as it notionally supports her (aborted) argument and it's at least a short-term 'win' that she won't fuss over the details of. Presumably, the best Black Hat can do would be to parrot what he has heard from Megan, without any understanding or critical thinking on his part. Due to his lack of understanding, he may even interject his own ideas (ones Megan never believed nor stated) into his posts. These are all consistent with him calling himself "pyramid honey truther". The word truther refers to people who reject established facts and instead choose to believe in conspiracies, like people who claim the moon landings never happened , or believe the US government is behind the 9/11 attacks . While a few conspiracy theories turn out to be true, most are easily proved to be fake, but this does not stop people from believing in them anyway, just like the two mentioned here, which are not easily dismissed by believers. This turns Megan, who likely has a reasonable and well-justified position, unwillingly into the source of conspiracy theories. Alternatively, he only does this to troll Megan (and Cueball), and everyone else that reads his Facebook page, just because he knows they will get annoyed. And also to state that this is an unimportant subject (a weird hill to die on) to make such a fuss over. No one would wish to eat that honey, anyway, having been abandoned to time for that long. He may see this as a completely uninteresting subject and thus makes fun of Megan with his statements. This would also be more in line with his usual behavior. It is also possible that Black Hat is simply mocking conspiracy theorists' obsessions with factually incorrect ideas, comparably to what may be the case in Secretary: Part 3 . The title text refers to the Eye of Providence , a symbol of an eye at the top of a pyramid, found on US currency and often associated with conspiracy theories of the Illuminati . Black Hat again refers to the pyramid honey found under the pyramids and calls it a conspiracy that goes all the way to the top . This usually means that the politicians (or the government agencies) ruling the country know about it, but keep it a secret from the public. But in this case, he mixes up terms and says it goes to the top of the pyramid (from the bottom), to where the giant eye is. As promised he also writes four words in all capital letters, shouting out the TRUTH! This comic is likely a satire of the stereotypical internet mindset and plays up the frequent confusion between legitimate scientific skepticism, where unsupported claims are rejected, and conspiracy-theory faux-skepticism, where legitimate evidence is rejected because it does not support a specific viewpoint. [Cueball and Megan are talking.] Cueball: Apparently honey has an infinite shelf life. They just found jars of it in the pyramids, still good. Megan: You know, I've heard that, and I don't think it's true. [Black hat enters.] Cueball: Really? Smithsonian magazine confirmed it. Megan: Believe it or not, I think their source is wrong. Black Hat: I believe you. [Megan has turned to Black Hat raising her hands.] Megan: See I read about the archaeologists who- Black Hat: I'm convinced. Gonna go to tell the internet. [Black Hat moved closer to Megan and Cueball.] Megan: Wait, are you sure? Let me explain why I- Black Hat: Don't need it. I've heard enough. [Zoom-in on Black Hat's head.] Black Hat: I've been looking for a weird hill to die on, and all the real ones are too far from my house. Black Hat: So this is mine. I'm now a pyramid honey truther. [Zoom back out. Black Hat starts walking left, pointing a finger up. Cueball and Megan turn to look after him.] Black Hat: Time to start a Facebook group and post a bunch of all-caps comments everywhere. Cueball: This could have gone better. Megan: Oh well.

Backups

Backups

https://www.xkcd.com/1718

https://www.explainxkcd.com/wiki/index.php/1718:_Backups

[Cueball] is sitting in an office chair at his desk, working on his laptop.] Cueball: Wait. My laptop is backing up some folders to this server... [Cueball scratches his chin in thought.] Cueball: ...Which is backing up its archives to that server... Cueball: ...And that server is syncing certain folders over to my laptop... [In a frame-less panel Cueball clicks on his laptop keyboard.] Click click click [Cueball is back to working normally on his laptop. A voice speaks to him from off-panel as indicated with a starburst at the right frame.] Cueball: ...But the exponential growth is slightly slower than Moore's law, so whatever. Off-panel voice: Oh my God. Off-panel voice: You are why we can't have nice things.

On his laptop, Cueball explores a cyclic path along which his files are being copied from storage to storage. His laptop (presumably the one he is on) is sending its files to a server, which sends its files to another server, which in turn syncs back a certain selection of files to his laptop. Cueball determines that this setup leads to an exponential growth, implying that each node in the cycle simply copies files over to the next without any effort to avoid duplicates. Indeed, each time a set of files completes a full cycle, duplicates of the same files are propagated. Moore's Law is an observation in computer engineering (made by engineer Gordon Moore in 1965) that states that the number of transistors we can fit in a chip will double approximately every two years. Cueball, who was rather alarmed, calms down when he realizes that the exponential growth of his backup is slower than that of Moore's Law. He reasons that as long as he keeps at the forefront of information storage, he will never run out of room. Assuming available disk capacity is proportional to number of transistors (this is roughly true for solid-state disks) or otherwise keeps pace with Moore's Law, this would imply it takes more than two years for his files to completely propagate through two servers and back to his laptop enough times to double in size (implying either an extremely slow transfer or an extremely weird backup system). The phrase "[this is] why we can't have nice things" is often used in response to incidents where someone abuses a well-meaning feature, with the abuse ultimately wiping out any benefits the feature was supposed to bring. In the comic, the person off-screen is commenting on the fact that Cueball is not using advances in storage capacity in a responsible manner. That is, rather than using the increased capacity to store more useful information, he is simply using it as a workaround to avoid having to make his backup strategy more efficient. This concept is further expanded upon in the title text when somebody, presumably the off-screen speaker, notes that Cueball may be better off taking fewer backups in the hopes of losing some data. Typically backups are taken in the hopes of not losing programs and data. However, if the inefficient backup solution presented is representative of the other things Cueball has created, it may be better to have it all be lost and in effect force it to be re-created in a hopefully superior way. There are some similarities to the Cueball who owns the computer in the 1700: New Bug and maybe also to the Code Quality series: 1513: Code Quality and 1695: Code Quality 2 , where Cueball speaks with Ponytail . Poor backup strategies are referenced in 1360: Old Files [Cueball] is sitting in an office chair at his desk, working on his laptop.] Cueball: Wait. My laptop is backing up some folders to this server... [Cueball scratches his chin in thought.] Cueball: ...Which is backing up its archives to that server... Cueball: ...And that server is syncing certain folders over to my laptop... [In a frame-less panel Cueball clicks on his laptop keyboard.] Click click click [Cueball is back to working normally on his laptop. A voice speaks to him from off-panel as indicated with a starburst at the right frame.] Cueball: ...But the exponential growth is slightly slower than Moore's law, so whatever. Off-panel voice: Oh my God. Off-panel voice: You are why we can't have nice things.

Superzoom

Superzoom

https://www.xkcd.com/1719

https://www.explainxkcd.com/wiki/index.php/1719:_Superzoom

[White Hat and Cueball are walking right. Cueball is looking down at a camera with a long lens he is holding in both hands.] Cueball: I love these superzoom cameras. For a few hundred dollars you can take pictures of Moon craters and Jupiter's clouds. [They stop, White Hat looks up in the air while Cueball does the same but through the camera he is holding up to his eye while taking pictures. The camera lens is further zoomed out and is clicking.] Cueball: And birds! See that speck up there? *Click* Cueball: Peregrine falcon! *Click* Cueball: It's banded, too. Want the number? [White Hat looks even further up as Cueball turns left and point the even further zoomed camera almost straight up while taking photos.] Cueball: And see that plane? *Click* Cueball: 787 Dreamliner *Click* Cueball: Japan Airlines. *Click* Cueball: Registration is— [White Hat looks back down on Cueball who has turned to the right holding the fully out-zoomed camera level to the right along the ground.] White Hat: OK, I'm sold—I want one. *Click* Cueball: They're in stock at the place on Union Road. *Click* Cueball: Hey, Kevin's working today! He's great.

In this comic, Cueball is showing off his new superzoom camera to White Hat . These are cameras with large zoom lenses, often 25× or higher magnification. He is very excited and starts by exclaiming how they can take detailed photos of the craters on the Moon , and (on better models) relatively large photos of Jupiter even with a resolution so individual clouds can be seen. (See examples of zoom on these objects here and here without cloud resolution though, but with Jupiter's four large moons and Saturn's rings .) He then spots a bird (which is just a speck in the sky) and uses the superzoom for birdwatching , which is a popular use for these cameras. He can see that it's a peregrine falcon and that it has been banded (ringed) and he can even read the number on the band (later it seems he has more trouble locating birds with his camera in 1826: Birdwatching ). He then spots an airplane and having taken a picture of it, he can tell that it is a 787 Dreamliner from Japan Airlines , and he can even make out the registration number. All this is possible , with a Nikon Coolpix P900 , which may not be much larger than the one Cueball stands with here, with an extremely long lens, and at the time of this comics release that type of camera could be bought at Amazon for less than $600. If that is within the limit Cueball gives of a few hundred dollars can be debated ... A SX-60, refurbished with optical zoom currently sells for $379. Its predecessor, the SX-50 sold, refurbished, for less than $200 until going out of stock. Note that before each comment he has taken a picture, presumably zooming further in after each photo of each new object, zooming out again before beginning with the next object. Finally, White Hat exclaims that he is sold and states that he also want a superzoom camera like Cueball's. Cueball then points the camera down the street takes a picture and tells White Hat that the shop on Union Road has these camera in stock, indicating that he can see this inside the store (or in their window). He then takes another image and is able to make out not only the worker Kevin inside, he also recognizes him and (as mentioned in the title text after taking yet a further zoomed in picture) notice a stain on Kevin's shirt. He seems to like Kevin and asks White Hat to tell Kevin about the stain when he goes there to buy a superzoom camera. (This was the first time the name Kevin was used in xkcd for a fictive person, see more in this trivia ). Even with the ability of these cameras, it would be difficult for Cueball to be able to make out a specific worker inside the store, but if he is standing near a window it is not impossible, and if he has a stain on his shirt, it is in the same league as spotting a band on a bird in the air. Of course he has to be in a spot where he can see straight to the front of the shop. The last panel and title text is also a remark on how such cameras can be used to spy on people for quite a far distance, which has often been (mis)used by paparazzi photographers taking pictures of famous people (often while almost naked or in a bikini or other bathing clothes). Now everyman gets this disconcerting possibility to spy on their neighbors and others for just a few hundred dollars. There are lenses that can do what Cueball describes about Jupiter's clouds in the comic (e.g., the Canon 5200mm ), but so far not such a small consumer camera as shown in the illustration. A couple of other factors that many people may not realize until after they've bought a consumer-level superzoom camera is that a) taking a hand-held picture at maximum zoom is typically rather blurry because the lens is magnifying all vibration and it's impossible to hold the camera steady enough (so a camera tripod would be needed), and b) that the lens' aperture at maximum zoom is typically much smaller than at normal focal lengths, with the result that the shutter time must be several times longer to get proper exposure, compounding the vibration / blurry problem. Modern superzoom cameras do have "image stabilization", which can mitigate blurriness due to vibration, but extreme telephoto photography is still more challenging than implied in the comic. Also having zoomed so much it is very hard to actually locate a moving plane or bird in the sky while looking at the image shown on the camera. And as shown in the comic the lens is zoomed very much in. Of course this could be done by Cueball after having found the flying object with much less zoom. But still if he loses sight of the bird while fully zoomed in it will be almost impossible to find it again without zooming back out. White Hat and Cueball have discussed photography before in 1314: Photos . [White Hat and Cueball are walking right. Cueball is looking down at a camera with a long lens he is holding in both hands.] Cueball: I love these superzoom cameras. For a few hundred dollars you can take pictures of Moon craters and Jupiter's clouds. [They stop, White Hat looks up in the air while Cueball does the same but through the camera he is holding up to his eye while taking pictures. The camera lens is further zoomed out and is clicking.] Cueball: And birds! See that speck up there? *Click* Cueball: Peregrine falcon! *Click* Cueball: It's banded, too. Want the number? [White Hat looks even further up as Cueball turns left and point the even further zoomed camera almost straight up while taking photos.] Cueball: And see that plane? *Click* Cueball: 787 Dreamliner *Click* Cueball: Japan Airlines. *Click* Cueball: Registration is— [White Hat looks back down on Cueball who has turned to the right holding the fully out-zoomed camera level to the right along the ground.] White Hat: OK, I'm sold—I want one. *Click* Cueball: They're in stock at the place on Union Road. *Click* Cueball: Hey, Kevin's working today! He's great.

Horses

Horses

https://www.xkcd.com/1720

https://www.explainxkcd.com/wiki/index.php/1720:_Horses

[Ponytail walks right with Cueball.] Ponytail: Drunk driving was less of a problem before cars. If you got on your horse drunk and fell asleep, it could just walk home. [Zoom in on Ponytail's torso; she holds up a palm to proffer an idea.] Ponytail: And if you tried to ride into a tree, the horse could be like "No." Ponytail: Forget human drivers – that's the benchmark we should be judging self-driving cars against. [The front end of a car, with the bottom of the windshield and the right side mirror just inside the panel is parked before White Hat. He is holding his hand, palm up, out to the left towards the car as he brags about it to Megan and Cueball standing in front of him admiring the car. At the top left of the panel a small frame with a caption is placed over the panels frame:] Soon: White Hat: This baby has 200 horses under the hood and 3.5 in the computer. Megan and Cueball: Ooooh!

The programming of self-driving cars has been in the news lately, as engineers and philosophers debate what rules the cars should follow in dangerous situations (for instance, what to do when forced to choose between hitting a pedestrian or swerving into oncoming traffic). Ponytail suggests one approach for solving this problem: to think of the car as behaving like a horse, using its own intelligence and ignoring dangerous commands in the interests of self-preservation. The comic begins with Ponytail claiming that in the old days, riding a horse or driving a horse drawn vehicle while drunk was less dangerous than drunk driving today. Given the higher speed and the denser traffic today this might seem plausible. On the other hand, modern cars have seat belts, airbags, and other features designed to save lives when crashes do occur; horses and horse-drawn vehicles lacked these safety features. However, if you do fall asleep on a horse, it will not suddenly walk into a tree or other obstacle, and it may actually just stop walking while you sleep. Ponytail expands the argument by stating the horse itself will be acting in the interest of its own self-preservation. She finally states that in a comparison of the ability of self-driving cars, we should forget humans, and instead it should be the ability of horses that should be the benchmark that the self-driving cars should be judged against. This segues into a scene in the near future where White Hat is bragging to Cueball and Megan about the features of a car (in order to sell the car to them) by comparing the features to those of horses. Car engines are traditionally measured in horsepower , which (roughly) compares the power output of the engine to that of a horse. White Hat goes a step further, claiming that the car (which is presumably self-driving) has an onboard computer with driving abilities equivalent to 3.5 horses, comparing the car's ability to mitigate for a drunk driver and/or avoid obstacles to that of a horse. White Hat has been depicted as a salesman before in 1350: Lorenz and similarly earlier in 260: The Glass Necklace . The title text features more comparisons of the car to horses. In the text, Randall states that the car has 240% of a horse's decision-making ability and produces only 30% as much poop as a horse. This statement is absurd because it claims that the self-driving car will be producing poop. It also suggests that even with 3.5 times as much horse-intelligence as a horse, the car may only have 2.4 times the decision-making ability, although the car in the title text could also just be a different car from the one in the comic. Note that riding a horse while drunk is in fact still dangerous and illegal in many places (for example, the UK and Ireland ). A badly-driven horse can throw off its owner, trample passersby, fall on bad surfaces, and destroy any wagon or carriage it's pulling. A self-driving car should be able to understand road rules, which a horse will not - which is presumably why the cars in the comic and the title text are both specified as being more intelligent than a horse. In 887: Future Timeline dogs driving cars are mentioned. Self-driving cars is a recurring topic on xkcd. In 1461: Payloads spacecraft mass is measured in horses. [Ponytail walks right with Cueball.] Ponytail: Drunk driving was less of a problem before cars. If you got on your horse drunk and fell asleep, it could just walk home. [Zoom in on Ponytail's torso; she holds up a palm to proffer an idea.] Ponytail: And if you tried to ride into a tree, the horse could be like "No." Ponytail: Forget human drivers – that's the benchmark we should be judging self-driving cars against. [The front end of a car, with the bottom of the windshield and the right side mirror just inside the panel is parked before White Hat. He is holding his hand, palm up, out to the left towards the car as he brags about it to Megan and Cueball standing in front of him admiring the car. At the top left of the panel a small frame with a caption is placed over the panels frame:] Soon: White Hat: This baby has 200 horses under the hood and 3.5 in the computer. Megan and Cueball: Ooooh!

Business Idea

Business Idea

https://www.xkcd.com/1721

https://www.explainxkcd.com/wiki/index.php/1721:_Business_Idea

[Cueball is standing next to a rolled down projector screen holding a hand up towards his off-panel audience, one from the audience speaks. It's is impossible to say if there are more than two persons off-panel, but it's also impossible to say if a person who speaks in one panel also speaks in one of the next, hence the numbering.] Cueball: Thank you all for coming. Cueball: I have an exciting business opportunity to share. Off-panel voice #1: Oh no. [Zoom in on Cueball's head. An off-panel person speaks twice.] Cueball: Now hear me out- Off-panel voice #2: Your ideas are always the worst. Cueball: No, no, this time it's a good one! I promise. Off-panel voice #2: Uh huh... [Front view of the screen with an image of a black gas pump, with the white hose snaking it's way up to the black handle. And arrow points to the middle of the hose where it is at it's highest point before the turn that goes to the handle. Cueball is pointing at the hose with a stick. Two different off-panel persons speaks to him.] Cueball: When someone fills their car with premium gas, some of it is left in the hose, and is dispensed to the next customer even if they've only paid for regular. If we create a network of- Off-panel voice #3: I'm leaving. Off-panel voice #4: Me too.

In this comic, Cueball announces he has "an exciting business opportunity to share". After hearing discouragement from his off-panel audience, he promises that "this time it's a good one", and goes on to explain his plan. Cueball's plan involves the premise that a small amount of premium gas is left in a fuel pump hose after a car driver fills their car up with premium gas. He states that even if the next customer only pays for regular gas , that they are still getting a small amount of the expensive premium gas. Though he doesn't get a chance to finish the outline for his plan, one can assume he planned to get premium fuel at regular prices, so he could then sell it for profit. After hearing the first part of his plan, two people from the off-panel audience announce they are leaving, clearly and correctly thinking that Cueball's idea is stupid and impractical. In reality, this would be an impossible business venture to execute. While in the United States often the same hose is used for the various octane fuels, the amount of fuel contained in the hose is relatively small (about a third of a gallon , or half a liter ) compared to the amount that is generally purchased, though for motorcycles the ratio is more significant . It is also illegal to resell fuel without the correct licenses, and it would be difficult, bordering on impossible, to have the fuel pump run to just the premium fuel out, and driving to each gas station would use more money to buy more fuel than any money that could be made back. This is not to mention trying to keep track of when someone purchased premium so as to be the next person to use that pump to extract those precious drops. 1499: Arbitrage implies a similar plan to extract wealth out of a small market inefficiency that, in reality, would be far too onerous to exploit, in this case reselling the free chips offered at some restaurants. The same idea was also used in 1110: Click and Drag where a person takes free drinks to resell . See also the what if? Cost of Pennies regarding why it would not be worth trying these kind of ventures out. The title text is another one of Cueball's fuel-based business ventures, as he says he plans to dig up fuel stations underground fuel storage tanks, to then sell the contents of. Again, illegal/theft, impractical, don't try it (though it would be much more profitable than his previous plan). The punchline is that a gas station's underground tank is "inaccessible" from the outside, just as there are some oil deposits that are inaccessible to traditional oil production techniques because no sufficient natural flow towards a well can be obtained. In the case of oil deposits, high-pressure fluids are pumped into the rock to break it up (" Hydraulic fracturing " also known as "fracking") and allow the oil to reach the well. Oil tanks, on the other hand, can be made accessible by puncturing them using (presumably) hydraulically powered tools (electrical power is inadvisable in the presence of high-vapor-pressure hydrocarbons due to the significant risk of fire and explosion caused by electrical sparking). The title text of 1662: Jack and Jill also refers to fracking. This comic originally shared name with 827: Business Idea , which was then renamed. There were no other relations between the ideas for the two comics, see Trivia . [Cueball is standing next to a rolled down projector screen holding a hand up towards his off-panel audience, one from the audience speaks. It's is impossible to say if there are more than two persons off-panel, but it's also impossible to say if a person who speaks in one panel also speaks in one of the next, hence the numbering.] Cueball: Thank you all for coming. Cueball: I have an exciting business opportunity to share. Off-panel voice #1: Oh no. [Zoom in on Cueball's head. An off-panel person speaks twice.] Cueball: Now hear me out- Off-panel voice #2: Your ideas are always the worst. Cueball: No, no, this time it's a good one! I promise. Off-panel voice #2: Uh huh... [Front view of the screen with an image of a black gas pump, with the white hose snaking it's way up to the black handle. And arrow points to the middle of the hose where it is at it's highest point before the turn that goes to the handle. Cueball is pointing at the hose with a stick. Two different off-panel persons speaks to him.] Cueball: When someone fills their car with premium gas, some of it is left in the hose, and is dispensed to the next customer even if they've only paid for regular. If we create a network of- Off-panel voice #3: I'm leaving. Off-panel voice #4: Me too.

Debugging

Debugging

https://www.xkcd.com/1722

https://www.explainxkcd.com/wiki/index.php/1722:_Debugging

[Cueball and White Hat are walking, while Cueball holds a hand out while talking.] Cueball: I was trying to figure out why my browser was acting weird. [In a frame-less panel they keep in walking, Cueball holds both hands up in front of him.] Cueball: Turns out it wasn't the browser-the issue was with my keyboard driver. [Zoom in on Cueball's upper torso as he is holding a finger up.] Cueball: Debugging that led me to a mysterious error message from a system utility... [Zoom out as Cueball holds up a miniature sword by the blade in one hand. White Hat turns his head around and looks at it while they keep walking.] Cueball: Anyway, long story short, I found the sword of Martin the Warrior. White Hat: I think at some point there you switched puzzles.

Cueball is telling White Hat about his attempt at debugging , i.e. the process of finding out what is causing a given (computer) problem, which can become increasingly difficult and convoluted. In this case, Cueball had a problem with his browser . His attempts to solve this problem led him to a problem with the device driver for his keyboard . Chasing that issue, he found an unclear error message from a system utility , and so on. Cueball decides to "make a long story short" by skipping several steps he believes are boring, and he unexpectedly reveals this process has led him to find the “ Sword of Martin the Warrior ”, a legendary relic from the children's fantasy novel series Redwall . This refers to the fact that a complicated riddled path was devised in the series that would lead to the sword, which is similar to the process of debugging, as it involves following clues to achieve an answer. But apart from that, they are entirely different. [ citation needed ] This is pointed out by White Hat who states that at some point in the process he switched from the puzzle of debugging to the Redwall puzzle of finding Martin's sword. Redwall has been referenced before, most prominently in 370: Redwall ; where Martin and the sword can be seen; but also in 1286: Encryptic and more recently in 1688: Map Age Guide . Googling an error message is a common method used during debugging, often leading to useful information. However, when there are no search results for a given message, it may mean the problem is so obscure that almost nobody had experienced it before. (See also 979: Wisdom of the Ancients about getting only one result.) Or, as the title text hints, it might mean it was a hidden clue to the location of Martin’s sword. [Cueball and White Hat are walking, while Cueball holds a hand out while talking.] Cueball: I was trying to figure out why my browser was acting weird. [In a frame-less panel they keep in walking, Cueball holds both hands up in front of him.] Cueball: Turns out it wasn't the browser-the issue was with my keyboard driver. [Zoom in on Cueball's upper torso as he is holding a finger up.] Cueball: Debugging that led me to a mysterious error message from a system utility... [Zoom out as Cueball holds up a miniature sword by the blade in one hand. White Hat turns his head around and looks at it while they keep walking.] Cueball: Anyway, long story short, I found the sword of Martin the Warrior. White Hat: I think at some point there you switched puzzles.

Meteorite Identification

Meteorite Identification

https://www.xkcd.com/1723

https://www.explainxkcd.com/wiki/index.php/1723:_Meteorite_Identification

[A caption is above a flowchart with only two boxes. The first box is a diamond shaped box with an arrow down to the next rectangular box below. Each box has a text.] How to identify a possible meteorite: Start No, it's not a meteorite.

Meteorites form when a meteoroid survives entrance through the Earth's atmosphere as a meteor . Thus, they are very rare rocks that come from space, and can stem from broken asteroids , the Moon , and sometimes (very rarely) even from Mars . The flowchart , though facetious, would actually work the vast majority of the time a person picks up a rock and believes it to be a meteorite, since any single rock one finds on the surface of the earth is almost definitely not a meteorite. Flowcharts are often used ( in xkcd ) to give the inexperienced a step-by-step process to follow (see a guide to flowcharts here: 518: Flow Charts ). Meteorite identification, however, is very difficult, so the brevity of this flowchart in a way pokes fun at the need for a flowchart to identify meteorites, since laypeople are not experienced enough to confirm that a rock is indeed a meteorite. A similar short flowchart as this has been used recently in 1691: Optimization , and another only two box chart was used in 1195: Flowchart . In the title text Randall mentions that the comic image is a link to the more detailed (now defunct, mirror here ) Meteorite or meteorwrong? Self-Test Check list flowchart at the Department of Earth and Planetary Sciences at Washington University in St. Louis . The authors of those resources notes that they have received many rock samples and photos (or even personal visits) from people claiming to have discovered meteorites and thus they would likely benefit from just providing people the shortcut flowchart from Randall, as a way of saying, "leave meteorite identification to the professionals." Randall also mentions in the title text that his favorite part of this real flowchart, which is the part where if anyone saw the "meteor" fall then it is 'NOT A METEORITE.' What he most likes about it is that this is not a mistake. First of all the chance of actually being near a falling meteorite is exceedingly small. From the flowchart was a link to a 64 point long checklist, which basically all ends in "..., then it's not a meteorite." In point 3 is noted the following: Since 1900, the numbers of recognized meteorite "falls" is about 690 for the whole Earth. That's 6.3 per year. Only 98 of those occurred in the US. That's less than 1 per year. Even when a meteorite is observed to fall, experienced meteorite hunters may find only a few stones when hunting dawn to dusk for a week. Second, meteors that can be seen falling almost definitely cannot be found on the ground immediately after. Any meteor big enough to glow and be visible while falling all the way to the ground will leave a large impact crater, rather than simply sit on the ground as a rock. Smaller meteors do not fall fast enough to glow all the way to the ground. Either they will burn up completely (not leaving any meteorite) or they will be slowed down before they burn all the way up (but typically end up much smaller than the original meteoroid). After that they will stop glowing and will brake even further until they reach a terminal velocity due to air resistance. Their small size, and lack of glow, make them practically impossible to follow with the naked eye even in daylight. If a person stands close by the impact location of a meteor it may be possible to hear a swish and a thunk, from when it passes by and then hit the ground. It will then be possible to locate the meteorite, but such a falling stone could also have been dropped from an airplane or by a storm. But in some few cases people have actually heard a real meteor falling and found it afterwards. This is what happened with the 690 events mentioned above. All this is described on How to Identify a Meteorite from The Meteorite Market which is linked in point 48 in the table from Washington University. But they did not see it fall! What Randall finds so funny about this part of the flowchart is that there are three arrows leading to the question "Did someone see it fall?", but from there only a "Yes" option is possible, and then this gives the result "Not a meteorite." This indicates that if you have found a rock that has no dark crust or regmaglypts (the options that by saying no takes the user to the question about seeing it fall), then it is not a meteorite, and then the only reason people might still believe it to be a meteorite must be because someone saw it fall and assumed it came from space (rather than more likely scenarios, such as a stone coming loose from a cliff or building, or being dropped by a bird or aircraft). If the rock actually has those thumbprint like impressions on the surface (that scientists call regmaglypts ) then the creator of the flowchart actually asks to see the rock (photo or sample). The other features that are interesting is if it has a dark thin crust (from the melting during entry), but only if it also has either regmaglypts or if it has a lighter color inside than the outer crust. See also 1405: Meteor about how people mistake the words meteorite with meteor. The many misspellings of meteorite is mentioned in point 63 in the table. [A caption is above a flowchart with only two boxes. The first box is a diamond shaped box with an arrow down to the next rectangular box below. Each box has a text.] How to identify a possible meteorite: Start No, it's not a meteorite.

Proofs

Proofs

https://www.xkcd.com/1724

https://www.explainxkcd.com/wiki/index.php/1724:_Proofs

[Miss Lenhart is standing facing left in front of a whiteboard writing on it. Eleven left aligned lines of writing is shown as unreadable scribbles. A voice interrupts her from off-panel right.] Miss Lenhart: ... Let's assume there exists some function F ( a,b,c ...) which produces the correct answer- Cueball (off-panel): Hang on. [In a frame-less panel Cueball is sitting on a chair at a desk with a pen in his hand taking notes.] Cueball: This is going to be one of those weird, dark magic proofs, isn't it? I can tell. [Miss Lenhart has turned right towards Cueball, who is again speaking off-panel. The white board is also off-panel.] Miss Lenhart: What? No, no, it's a perfectly sensible chain of reasoning. Cueball (off-panel): All right... [Miss Lenhart is facing the whiteboard again writing more scribbles behind some of the lines from before (the first line has disappeared). The lines that have more text added are now number three and five (four and six before). Cueball again speaks off-panel.] Miss Lenhart: Now, let's assume that the correct answer will eventually be written on the board at the coordinates ( x, y ). If we— Cueball (off-panel): I knew it!

Miss Lenhart is teaching a math class. She begins a proof when one of her students ( Cueball ) interrupts her asking if this is one of those dark-magic (unclear, incomprehensible) proofs. She claims no, but in a matter of seconds Cueball is calling out that he was right. The proof she starts setting up resembles a proof by contradiction . However, after Cueball's interruption Miss Lenhart's proof takes a turn for the absurd: rather than assuming there will be a point in the function that correlates to co-ordinates (x, y), Miss Lenhart assumes that the act of writing numbers on the board will correlate to co-ordinates (x, y). A normal proof by contradiction begins by assuming that a particular condition is true; by demonstrating the implications of this assumption, a logical contradiction is reached, thus disproving the initial assumption. One example of a proof by contradiction is the proof that √2 is an irrational number: Q.E.D. Alternatively, instead of a proof by contradiction the setup could be for a one way function. For example, it is relatively easy to test that a solution to a differential equation is valid but choosing the correct solution to test can seem like black magic to students. The way that Ms Lenhart's proof refers to the act of doing math itself, is characteristic of metamathematical proofs, for example Gödel's incompleteness theorems , which, at first sight, may indeed look like black magic, even if in the end they must be a "perfectly sensible chain of reasoning" like the rest of good mathematics. While typical mathematical theorems and their proofs deal with such mathematical objects as numbers, functions, points or lines, the metamathematical theorems treat other theorems as objects of interest. In this way you can propose and prove theorems about possibility of proving other theorems. For example, in 1931 Kurt Gödel was able to prove that any mathematical system based on arithmetics (that is using numbers) has statements that are true, but can be neither proved nor disproved. This kind of metamathematical reasoning is especially useful in set theory , where many statements become impossible to prove or disprove if the axiom of choice is not taken as a part of the axiomatic system. Using a position on the blackboard as a part of the proof is a joke, but it bears a resemblance to Cantor's diagonal argument where a position in a sequence of digits of a real number was a tool in a proof that not all infinite sets have the same cardinality (rough equivalent of the number of elements). This "diagonal method" is also often used in metamathematical proofs. The axiom of choice itself states that for every collection of nonempty sets, you can have a function that draws one element from each set of the collection. This axiom, once considered controversial, was added relatively late to the axiomatic set theory, and even contemporary mathematicians still study which theorems really require its inclusion. In the title text the decision of whether to take the axiom of choice is made by a deterministic process, that is a process which future states can be developed with no randomness involved. Determinacy of infinite games is used as a tool in the set theory, however the deterministic process is rather a term of the stochastic processes theory , and the dynamical systems theory , branches of mathematics far from the abstract set theory, which makes the proof even more exotic. The axiom of choice was mentioned earlier in 804: Pumpkin Carving and later in 982: Set Theory , another comic about a math class with a similar theme on how teachers teach their student mathematical proofs. Although Miss Lenhart did retire a year ago after 1519: Venus , she seems to have returned here for a math course at university level, but continues the trend she finished with in her prior class. A very similar Miss Lenhart comic was later released with 2028: Complex Numbers . [Miss Lenhart is standing facing left in front of a whiteboard writing on it. Eleven left aligned lines of writing is shown as unreadable scribbles. A voice interrupts her from off-panel right.] Miss Lenhart: ... Let's assume there exists some function F ( a,b,c ...) which produces the correct answer- Cueball (off-panel): Hang on. [In a frame-less panel Cueball is sitting on a chair at a desk with a pen in his hand taking notes.] Cueball: This is going to be one of those weird, dark magic proofs, isn't it? I can tell. [Miss Lenhart has turned right towards Cueball, who is again speaking off-panel. The white board is also off-panel.] Miss Lenhart: What? No, no, it's a perfectly sensible chain of reasoning. Cueball (off-panel): All right... [Miss Lenhart is facing the whiteboard again writing more scribbles behind some of the lines from before (the first line has disappeared). The lines that have more text added are now number three and five (four and six before). Cueball again speaks off-panel.] Miss Lenhart: Now, let's assume that the correct answer will eventually be written on the board at the coordinates ( x, y ). If we— Cueball (off-panel): I knew it!

Linear Regression

Linear Regression

https://www.xkcd.com/1725

https://www.explainxkcd.com/wiki/index.php/1725:_Linear_Regression

[Two square panels show identical sets of scattered black dots, with only the red additions being different.] [The left panel shows a slightly rising red line drawn through the middle of the panel, passing near a few dots but not obviously related to most of them. A red text is below the dots:] R 2 =0.06 [The right panel shows many of the dots connected by red lines to form a stick figure of a man resembling the constellation Orion, with the hand on the reader's right raised and holding an object. A red text is below the dots:] Rexthor, the Dog-Bearer [A caption is below and spanning both panels:] I don't trust linear regressions when it's harder to guess the direction of the correlation from the scatter plot than to find new constellations on it.

Linear regression is a method for modeling the relationship between multiple variables. In the simplest case, it can be used for two variables wherein the model determines a " best-fit " line through a scatter plot of the datasets, together with a coefficient of determination , usually denoted r 2 or R 2 . When only two variables are included in the regression, R 2 is merely the square of the correlation between the two variables. R 2 is a number between 0 and 1 that indicates how well one variable can be used to predict the value of another. A value of 1 means perfect correlation, while a value close to 0 indicates a weak relationship between the variables. A constellation is the region of sky containing an asterism ; an asterism is a pattern created by linking the apparent positions of stars as seen in the sky from Earth. Strictly speaking, Randall's "Rexthor" is an asterism, although "constellation" is used informally in place of "asterism" by even seasoned astronomers. Different civilizations have recognized different constellations (the modern IAU, for example, lists 88 "official" constellations), and one could create their own constellations by connecting assorted points. In this comic, a set of data has had linear regression and some form of statistical analysis applied to it, indicating that there is low correlation between the two. The data points are so widely scattered that (as noted in the comic) it is easier to connect the data points in a constellation-like pattern than it is to determine whether the correlation is negative or positive (without looking at the trendline, of course). Because of this, Randall suggests we should be suspicious of any conclusions drawn from this data. The comic is somewhat misleading, since the data in the graph actually has an R 2 of 0.02, only a third of what Randall claims. An example of published research with an R 2 of 0.06 where the association in the graph is noticeable (if not strong) can be found here (figure 2 has r = 0.25 which corresponds to R 2 = 0.06). In addition, it is hard to see the association in the comic's graph because relatively few points are plotted. In a data set with 1000 observations and R 2 = 0.06, any association between the two variables would be quite clear. The lines connecting the stars in this "constellation" create a crude illustration of a person with an outstretched arm holding up a dog, which could be a reference to the film Life is Beautiful where a waiter carries a dog on his tray without realizing. The name "Rexthor the Dog Bearer" could be a spoof on Thor , a Norse god who wields a hammer. By replacing his hammer with a dog and adding "Rex" (an archetypal dog name, but also meaning king as in king of the dinosaurs T-rex), Randall may have created a comical, dog-bearing version of Thor. The 95% confidence interval in statistics is such a range of an estimate, that it is expected to contain the real value (the estimated population parameter) 95% of the time. The confidence interval is a standard method to provide evaluation of the estimation error in statistics. On the right panel the resulting estimate seems to be a drawing, so the 95% confidence interval would be a set of drawings, expected to contain the correct drawing in 95% of samples where it is calculated. According to the title text, the interval in this particular sample also includes a cat and a teapot, so we can only make extremely vague statements in order to maintain 95% confidence. The teapot may be a reference to Russell's teapot , or possibly to the "teapot" asterism in the constellation Sagittarius. Alternatively it is just because the "dog" actually looks more like a teapot than a dog, and Randall noticed this and added it in the title text. In the latter case, the two first suggestions are just another example on how humans see patterns also where there are none to find, like those of pareidolia mentioned in 1551: Pluto . [Two square panels show identical sets of scattered black dots, with only the red additions being different.] [The left panel shows a slightly rising red line drawn through the middle of the panel, passing near a few dots but not obviously related to most of them. A red text is below the dots:] R 2 =0.06 [The right panel shows many of the dots connected by red lines to form a stick figure of a man resembling the constellation Orion, with the hand on the reader's right raised and holding an object. A red text is below the dots:] Rexthor, the Dog-Bearer [A caption is below and spanning both panels:] I don't trust linear regressions when it's harder to guess the direction of the correlation from the scatter plot than to find new constellations on it.

Unicode

Unicode

https://www.xkcd.com/1726

https://www.explainxkcd.com/wiki/index.php/1726:_Unicode

[Cueball is standing in a river close to it's right bank, the water reaching up to his thighs. He is holding on to a traffic sign standing towards right. It has a label and an arrow below this pointing to the right bank. With his other arm he is pointing to the left at the advancing water masses. Further up the river is another street sign this sign has an exclamation mark inside a triangle. The water flow is indicated with several lines on the river surface, mainly moving along the river, but around Cueball and the signs there are circular lines. In the distance on the left bank of the river two people are standing and making gestures with raised arms. The left has white hair (could be either sex) and the other is a Cueball-like guy. A third sign is lying on the ground to the left of them face down. Behind them is a slope up to a road with a parked car. The road continues out over a a bridge that crosses the river. The river which passes under it both left and right of a central pillar. At that distance the right bank of the river (and thus the right end of the bridge) is not visible, being outside the panel. On each river bank grass can be seen and on the right bank also a small stone.] Cueball: No, go this way, not- Cueball: Are you even listening!? Cueball: ... Hey! That's not what that area is for! Sign with arrow: Detour Sign with triangle: ! [Caption below the panel:] Watching the Unicode people try to govern the infinite chaos of human language with consistent technical standards is like watching highway engineers try to steer a river using traffic signs.

Cueball is a highway engineer that has been placing two traffic signs in a river trying in vain to guide the water flow and thus he ends up talking to the water trying to make it take a detour instead of going under the bridge. On the distant bank two other engineers are arguing, with gestures, in presumably a heated manner (probably about where to place a third sign, lying next to them at the the water, to make it behave a certain way) As rivers flow according to the landscape, this plan will not work and the river will continue on its course. Cueball is very frustrated by this and is still trying to make the river obey the traffic laws. The caption lays out the punchline: The comic compares the useless approach of Cueball attempting to divert a flowing, moving river with fixed signs that do nothing, with the Unicode Consortium 's attempt to define the diverse and ever-changing human language with strict technical standards. Unicode is a largely successful attempt to have a standard for representing all possible letters, numerals, digits and symbols that make up human writing in all languages. This includes the roman letters used in this article, characters with modifiers like ê (both with the common characters as well as the modifiers selectable separately), logographic characters like in Chinese, syllabic writing system like Japanese, right-to-left and/or top-to-bottom writing systems, mathematical symbols and many other writing systems. Emoji , one of the trendier and newer Unicode blocks, are also referenced in the title text (see below). The symbols on the signs in the river are real road signs, but interestingly enough they also both exist in Unicode, with the warning sign triangle with an exclamation mark ⚠ having code (U+26A0) and the black, rightwards arrow ➡ having code (U+271A) . As can be imagined, coping with the wide variety of character sizes, orientations, ways they can be modified, capitalization rules, etc. can get to be very challenging as the Unicode Consortium tries to write rules that accommodate how printed language is actually used. Emoji have become a recurrent theme on xkcd. The title text refers to a proposal to add three dinosaur heads to the official list of emoji. This is likely to stir a glorious internet argument between a half-dozen opposing (and pedantic ) camps that may now be brought together, such as the following: See also this discussion about this comic on the Unicode mailinglist ... Highway engineers were also the subject of 253: Highway Engineer Pranks and 781: Ahead Stop . [Cueball is standing in a river close to it's right bank, the water reaching up to his thighs. He is holding on to a traffic sign standing towards right. It has a label and an arrow below this pointing to the right bank. With his other arm he is pointing to the left at the advancing water masses. Further up the river is another street sign this sign has an exclamation mark inside a triangle. The water flow is indicated with several lines on the river surface, mainly moving along the river, but around Cueball and the signs there are circular lines. In the distance on the left bank of the river two people are standing and making gestures with raised arms. The left has white hair (could be either sex) and the other is a Cueball-like guy. A third sign is lying on the ground to the left of them face down. Behind them is a slope up to a road with a parked car. The road continues out over a a bridge that crosses the river. The river which passes under it both left and right of a central pillar. At that distance the right bank of the river (and thus the right end of the bridge) is not visible, being outside the panel. On each river bank grass can be seen and on the right bank also a small stone.] Cueball: No, go this way, not- Cueball: Are you even listening!? Cueball: ... Hey! That's not what that area is for! Sign with arrow: Detour Sign with triangle: ! [Caption below the panel:] Watching the Unicode people try to govern the infinite chaos of human language with consistent technical standards is like watching highway engineers try to steer a river using traffic signs.

Number of Computers

Number of Computers

https://www.xkcd.com/1727

https://www.explainxkcd.com/wiki/index.php/1727:_Number_of_Computers

[A graph with two red lines. The X-axis is a time-line with eight ticks with every second tick labeled below the axis, ranging from around 1940 to 2030. The Y-axis is a logarithmic count ranging from 1 to 1 billion. There are 12 ticks with the first and then every third tick after that larger than the two ticks in between. All the large ticks are labeled, but only the first two of the small ticks are similarly labeled. Labels are written to the left of the axis. All labels on both axes are written in gray. The first red line is a straight line (thus exponentially growing), starting close to the bottom left corner eventually reaching the upper right edge of the graph. The other red line begins around 1990 and has three straight steps. Each step is labeled with gray text, the last part of the line (after the present 2016), is dotted. Both of the red lines have an arrow pointing to them with a label above the arrow.] Left red line: Number of computers created Right red line: Number of computers destroyed by hurling them into Jupiter Labels on right red line: Galileo probe Galileo orbiter Juno (scheduled) Y-axis: 1 billion 1 million 1,000 100 10 1 X-axis: 1960 1980 2000 2020 [Caption below the panel:] NASA needs to pick up the pace if they ever want to finish the job.

This comic shows a semi-log plot with two red lines. The first line shows the increasing rate that computers have been created since the first came around in the 1940s. The graph shows this to occur around 1946. ( The precise date can be discussed but it was around that time that the concept began to be applied to real working machines.) After the first computer, the number of computers created is shown to increase in a roughly straight line, indicating exponential growth . At the time of this comic's release in 2016, the curve has passed 10 billion computers, and its projection into the 2020s predicts that the number of computers will keep rising exponentially for at least 10 years to come. The other plot on this graph represents all the computers destroyed by throwing them into Jupiter . So far this is only true for the computers on two space probes : those on the Galileo orbiter and its probe . The latter's mission was to fly into Jupiter so it went first in 1995; the orbiter went only after it had completed its mission in 2003. That constitutes the first two steps on the graph. Recently the Juno space probe entered into orbit (as only the second after Galileo), and that was celebrated with 1703: Juno on xkcd. Juno's main mission has hardly begun yet; as at the time of this comic's release, it is not even in its final orbit. But once its mission is completed, it will also crash into Jupiter thus destroying a third computer. This is shown as the third step, but this section is shown with a dotted line, as the destruction may still fail if NASA loses contact with the probe before giving it the order to deorbit into Jupiter. This is scheduled to occur in 2018. All three steps on the graph fits with these years. (Note the number of computers created is not drawn with a dotted line into the future, probably because Randall believes this continued increase in numbers of computers to be quite certain over the next 10-20 years, whereas the outcome of a space probe mission is never certain, even when the probe is already in orbit and only 1½ years before scheduled deorbit!) Space probes sent to Jupiter are typically scheduled to deorbit and fall into Jupiter's atmosphere. There can be several reasons for this, but one very important reason is to avoid contaminating Jupiter's moons with Earth pathogens , especially the four Galilean moons including Europa which may harbor life . Also the huge gravity well of Jupiter that would have to be overcome for such a probe to leave the planet again makes it impossible to have an orbiting probe return to Earth with samples. The caption below the comic humorously implies that NASA's reasons for causing the probes to deorbit into Jupiter is merely an attempt to destroy all the computers of the world. The caption notes that they are failing horribly, given that they have destroyed only three computers out of more than 10 billion. However, due to the semi-log scale, those three computers appear to have more significance than they actually have. The caption states that NASA really needs to pick up the pace (having only destroyed two since the 1940s, when computers were created), if they wish to actually finish the job of destroying all computers by hurling them into Jupiter. In addition, seeing as there have been many computers destroyed by other means, NASA will never actually catch up, no matter how hard they try, making this statistic even more irrelevant. Destroying unwanted objects by hurling them into Jupiter pokes fun at the common science fiction trope of destroying objects by hurling them into the Sun [1] . Hurling objects into the Sun is in fact extremely difficult because of the need to cancel out the orbital velocity of the earth. Randall may be referencing calculations ( [2] , see item 11) that show that hurling items into Jupiter requires 38% less energy than hurling them into the Sun. The title text continues the caption by mentioning that in NASA's annual reports they try to make their numbers look better by counting the redundant computer systems on Galileo and its probe, thus doubling the numbers of destroyed computers to four. This of course makes no big difference given the exponential growth of computer production, which is also noted. This indicates that this is a top priority for NASA. That NASA might try to make themselves look better in a report by doubling a number could be realistic, presumably for political reasons or to get better funding. [A graph with two red lines. The X-axis is a time-line with eight ticks with every second tick labeled below the axis, ranging from around 1940 to 2030. The Y-axis is a logarithmic count ranging from 1 to 1 billion. There are 12 ticks with the first and then every third tick after that larger than the two ticks in between. All the large ticks are labeled, but only the first two of the small ticks are similarly labeled. Labels are written to the left of the axis. All labels on both axes are written in gray. The first red line is a straight line (thus exponentially growing), starting close to the bottom left corner eventually reaching the upper right edge of the graph. The other red line begins around 1990 and has three straight steps. Each step is labeled with gray text, the last part of the line (after the present 2016), is dotted. Both of the red lines have an arrow pointing to them with a label above the arrow.] Left red line: Number of computers created Right red line: Number of computers destroyed by hurling them into Jupiter Labels on right red line: Galileo probe Galileo orbiter Juno (scheduled) Y-axis: 1 billion 1 million 1,000 100 10 1 X-axis: 1960 1980 2000 2020 [Caption below the panel:] NASA needs to pick up the pace if they ever want to finish the job.

Cron Mail

Cron Mail

https://www.xkcd.com/1728

https://www.explainxkcd.com/wiki/index.php/1728:_Cron_Mail

[Cueball is sitting at a table in an office chair working on his laptop. Ponytail walks up to him.] Cueball: I've been getting these "You have new mail" UNIX notifications for like 15 years, but I've never bothered to figure out what it's talking about. [Ponytail has stopped behind Cueball who is typing on his laptop. When Ponytail (and later Cueball) mentions code, the text uses both small and capital letters (as opposed to only capital letters in all other text).] Ponytail: Look in /var/mail? Cueball: OK... Cueball: Oh, wow, there's like a gigabyte of stuff from Cron in here. [In a frame-less panel Ponytail is facepalming. Cueball is replying from off-panel with a starburst indicating his position.] Ponytail: *Sigh* Ponytail: You should fix your Cron, then point "MAILTO=" somewhere you actually see- Cueball (off-panel): Better idea: [Same setting as panel 2 but Cueball is visibly typing on the laptop as shown with three small curved lines over his hands on the keyboard.] Cueball: export MAILTO=/etc/crontab Cueball: There. Your move, Cron. Ponytail: Wow. Hardball. Cueball: Let's see how important it thinks that mail really is.

On Unix -like systems, cron is a system utility that runs tasks on a schedule. This program has been around since the early days of Unix and has not changed much - it is still one of the most widely used functions in modern operating systems. Many administrative tasks on servers are automated using cron, including monitoring and updates. When a cron job produces output, cron's default behavior is to send an email to the user account under which the job ran. However, in most situations, an email address has not been set up for that user, so the email is instead written to a mailbox file. Most Unix shells will notify the user with a message like "You have new mail" when this mailbox file is updated, but if the user doesn't know how to check this mail file, they will likely just ignore the message. In this case, Cueball has been ignoring his mailbox for fifteen years. When he finally learns where to look, he discovers more than a gigabyte worth of messages from the cron program, the vast majority of which are likely meaningless. Ponytail says to Cueball "fix your cron" (likely meaning he should fix the task that's generating the output so that it doesn't do so), then set a parameter that tells cron to send email to an address he actually checks. (He could also opt to direct the mails to /dev/null , which would discard them, or simply disable the mail in the crontab.) Cueball, however, interprets the tremendous amount of email as spam and decides to redirect the emails to /etc/crontab , the main configuration file that contains all of cron's scheduling information. He apparently believes that this will either stop the emails or cause cron to spam itself instead. In reality, this will not cause significant problems as the MAILTO environmental variable in cron takes an email address or usernames on the local system and attempts to send emails to them. It will not write or append output to a local file like /etc/crontab . Thus when cron attempts to email /etc/crontab the mail program cron uses will generate an error saying it can't find the user /etc/crontab . For example, if you create the following crontab: installed on a user named me on a system called mycomputer then you will see a new error messages email to you (located in /var/mail/me ) stating it can't send email to a user named /etc/crontab and the undelivered email is being returned to the sender. The error email will look like the following: The title text shows that Cueball is somewhat aware of what cron does, including the fact that it's existed pretty much unchanged for several decades, but he hasn't bothered to really get into understanding it, treating it more as a foe to vanquish rather than as a tool to understand and use. [Cueball is sitting at a table in an office chair working on his laptop. Ponytail walks up to him.] Cueball: I've been getting these "You have new mail" UNIX notifications for like 15 years, but I've never bothered to figure out what it's talking about. [Ponytail has stopped behind Cueball who is typing on his laptop. When Ponytail (and later Cueball) mentions code, the text uses both small and capital letters (as opposed to only capital letters in all other text).] Ponytail: Look in /var/mail? Cueball: OK... Cueball: Oh, wow, there's like a gigabyte of stuff from Cron in here. [In a frame-less panel Ponytail is facepalming. Cueball is replying from off-panel with a starburst indicating his position.] Ponytail: *Sigh* Ponytail: You should fix your Cron, then point "MAILTO=" somewhere you actually see- Cueball (off-panel): Better idea: [Same setting as panel 2 but Cueball is visibly typing on the laptop as shown with three small curved lines over his hands on the keyboard.] Cueball: export MAILTO=/etc/crontab Cueball: There. Your move, Cron. Ponytail: Wow. Hardball. Cueball: Let's see how important it thinks that mail really is.

Migrating Geese

Migrating Geese

https://www.xkcd.com/1729

https://www.explainxkcd.com/wiki/index.php/1729:_Migrating_Geese

[Caption above the panel:] Understanding Migration of Geese [20 geese are shown flying in a typical migratory V-formation. As they are shown in silhouette it is not possible to determine if they are seen from above or from below. They are flying toward the top of the image with the first goose close to the top in the middle of the image. There is one head goose, and then there are 7 geese in the left arms and 9 geese in the right arm. Behind the left arm there are two stragglers that are not in line with the others, but closer to the middle than those above and not as close to each other as the rest but still flying in the same direction. Finally there is one goose at the bottom right corner flying at a 45 degree angle away from the other to the right. The first goose is flapping its wing, which is also the case with six other geese, no. 4 and 6 in the left and 3, 5 and 6 in the right arm as well as the middle of the two in the rear towards the middle. The rest are soaring with straight wings and all of these look the same except no. 7 in the right arm which has two tails, which both goes ahead of the wings, making it look like a plane with two engines. The head goose and 5 of the 9 geese in the right arm as well as the one bottom right are labelled with and arrow pointing to them from the label. The front goose has the label in front to the left, the other have it in front to the right, except the second last in the arm which has the label inside the V and one flying away which has the label right above it. The two behind and right of the left arm have one label behind them with two arrows from the label pointing at both geese. There is a thick curvy line in front of geese no. 3 to 5 in the left arm. In front of that line is a thinner broken line. In front of this is a label written with the same curvature. There are two areas surrounded by dotted lines. The first one is behind the last of the left arms geese, extending in the same direction for a distance of about two geese. It has a label above and left with and arrow pointing to it. The other area is in the middle of the V forming a loose triangular structure with a label inside.] Head goose: Head goose (4 th in line to the British throne) Right no. 1: Quarterback Right no. 3: Comptroller Right no. 5: Migration abort goose Right no. 7: Twin-engine model Right no. 8: CIA informant Bottom right corner: Kevin Behind center: Backups In front of left no. 3-5: Shock front Empty area behind left arm: Missing valence geese Empty area in center: Stealth cargo being escorted

Migrating refers to the changing of a habitat, which happens every year with birds like geese that travel long distances to avoid cold seasons and get back to the food in the summer time. When geese fly to their new habitat, they tend to fly in a very clear V formation . The V formation improves the efficiency of flying birds, particularly over long migratory routes. All the birds except the first fly in the upwash from one of the wingtip vortices of the bird ahead. The upwash assists each bird except for the "leading" one in supporting its own weight in flight, saving them up to 20% of the energy needed. It should be noted that geese do have family structures with adult geese in "alpha" positions, but not a strict ranking order. An individual's position in formation flights is coincidental and constantly changing, so that the goose at the point of the formation can pull back and rest in the V wings while others "lead" the swarm. Popular earlier beliefs about an "alpha goose" heading a formation for the entire flight is a myth, easily disproved by watching geese formations in flight. This comic shows such a formation with 20 geese, with several geese and areas in the V formation labeled, giving different roles to the geese and assigning these areas a new meaning. See the table below . Apart from a "twin engine" goose in the bottom right arm of the V the only part of the formation that would not normally be seen is Kevin, who flies off at a 45-degree angle. In that direction there is no aerodynamic help from the other birds, and in the title text the rest of the geese also exclaim, "Dammit, Kevin" when he (again?) tells them that he has a great new idea for a migration (maybe referring to the new direction). This is either a reference to the fact that migrating birds manage to consistently arrive in the same general area every year, or to the way that vacations are sometimes suggested (by humans): "I thought of an idea for a vacation..." This was only the second time the name Kevin was used in xkcd for a fictive person, see more in this trivia . [Caption above the panel:] Understanding Migration of Geese [20 geese are shown flying in a typical migratory V-formation. As they are shown in silhouette it is not possible to determine if they are seen from above or from below. They are flying toward the top of the image with the first goose close to the top in the middle of the image. There is one head goose, and then there are 7 geese in the left arms and 9 geese in the right arm. Behind the left arm there are two stragglers that are not in line with the others, but closer to the middle than those above and not as close to each other as the rest but still flying in the same direction. Finally there is one goose at the bottom right corner flying at a 45 degree angle away from the other to the right. The first goose is flapping its wing, which is also the case with six other geese, no. 4 and 6 in the left and 3, 5 and 6 in the right arm as well as the middle of the two in the rear towards the middle. The rest are soaring with straight wings and all of these look the same except no. 7 in the right arm which has two tails, which both goes ahead of the wings, making it look like a plane with two engines. The head goose and 5 of the 9 geese in the right arm as well as the one bottom right are labelled with and arrow pointing to them from the label. The front goose has the label in front to the left, the other have it in front to the right, except the second last in the arm which has the label inside the V and one flying away which has the label right above it. The two behind and right of the left arm have one label behind them with two arrows from the label pointing at both geese. There is a thick curvy line in front of geese no. 3 to 5 in the left arm. In front of that line is a thinner broken line. In front of this is a label written with the same curvature. There are two areas surrounded by dotted lines. The first one is behind the last of the left arms geese, extending in the same direction for a distance of about two geese. It has a label above and left with and arrow pointing to it. The other area is in the middle of the V forming a loose triangular structure with a label inside.] Head goose: Head goose (4 th in line to the British throne) Right no. 1: Quarterback Right no. 3: Comptroller Right no. 5: Migration abort goose Right no. 7: Twin-engine model Right no. 8: CIA informant Bottom right corner: Kevin Behind center: Backups In front of left no. 3-5: Shock front Empty area behind left arm: Missing valence geese Empty area in center: Stealth cargo being escorted

Starshade

Starshade

https://www.xkcd.com/1730

https://www.explainxkcd.com/wiki/index.php/1730:_Starshade

[Megan and Ponytail are walking.] Megan: Space telescopes could see exoplanets better if they used free-floating opaque discs to block the stars' glare. [They stop walking in this zoom in on their heads. Ponytail has turned towards Megan.] Megan: They thought about including one with the Webb telescope, but cut it to save money. Ponytail: Well... does it have to be their disc? [In this frame-less panel Megan is left standing as Ponytail turns and walks away.] Megan: What do you mean? Ponytail: Like, if I Kickstart a starshade for them? Megan: Um. Would you at least warn them? Ponytail: Eh. Whatever. [Cueball and Hairbun, both wearing headsets, are sitting on one legged stools on either side of a slim desk with two computers screens on top of it. Each are looking at their own screens while typing on a keyboard in front of them. Hairbun is pointing at her screen. A small frame is overlaid on the top of the panels frame with a caption:] NASA, 2018: Cueball: Initiating Webb calibrat- Cueball: Aaaaa ! What the hell is that!? Hairbun: Hey, look, exoplanets!

Megan and Ponytail are talking about space telescopes in general. Megan says that these telescopes could see exoplanets better by using occulting disks , in the form of free floating opaque discs, that could block out light from the exoplanets' stars, thus enabling the telescopes to see the weak light from the planets when the glare of the stars has been diminished. She continues by explaining that the scientists behind the new James Webb Space Telescope , at the time of the comic scheduled to launch in 2018, thought about including such a disk (a starshade ), but that it was cut for budget reasons . Ponytail asks if it has to be their own disk, and then decides to kickstart a fundraiser to build a starshade. Ponytail is referring to the crowdfunding site Kickstarter , although there is no actual project for a starshade for Webb (or for the New Worlds Mission; see title text explanation) on Kickstarter. Megan asks her to at least warn the scientists if she makes the starshade, but Ponytail just replies "whatever". The final panel shows the NASA control center in 2018 when the Webb telescope is being calibrated. It turns out that Ponytail succeeded and did indeed not warn the scientists. Cueball is surprised by the disc -- and possibly by what the disc might have printed on it, given its crowdfunded origins -- but Hairbun immediately notices exoplanets, implying that Ponytail's plan worked. Note that the telescope has partners from 20 countries and is being operated not only by NASA but also by European Space Agency (ESA), Canadian Space Agency (CSA), and the Space Telescope Science Institute (STScI). The best known space telescope is the Hubble Space Telescope , which was launched back in 1990. The Webb telescope is seen as a successor instrument to Hubble and, because its instruments are designed to work primarily in the infrared region of the electromagnetic spectrum, also as a successor to the Spitzer Space Telescope launched in 2003. In addition to having more sensitive sensors and being larger, Webb will also be located near the L2 Earth–Sun Lagrangian point , and thus not in orbit around Earth. This means that it can keep focusing on a specific point for longer times, while Hubble can see a given point for only about half an hour before moving behind Earth again. When operating in the infrared range as the Webb telescope does (from middle infrared to red and orange visible light), it is important to be outside the atmosphere or at least on very high mountains. Another important feature is to keep the temperature constant and very cool. Since the Webb telescope is always in the light of the sun, this is achieved using protection from a large sunshield . The title text mentions the New Worlds Mission . This mission is to find exoplanets (hence the name New Worlds) by applying a starshade to block the light of distant stars, so that the planets around the stars are more visible. All discovered exoplanets so far have been found indirectly and not by direct visual observation. The starshade proposed by the New Worlds Mission is a spacecraft designed to work in tandem with a space telescope (not necessarily just the Webb telescope). It is a large occulter that blocks a star's light. One problem with this concept is that light coming from the target star would diffract around the disc and constructively interfere along the central axis. Thus the starlight would still be easily visible, making planet detection impossible. In order to avoid this problem, the proposed starshade is a sunflower-shaped coronagraph disc. The "petals" of the "sunflower" shape are designed to eliminate this diffraction, making exoplanet observation possible. The starshade would fly 72,000 km (45,000 mi) in front of a space telescope (between the telescope and a target star) in order to work. A video demonstrating the starshade is available on the Wikipedia page for the New Worlds Mission. The title text explains that NASA actually sponsored this mission's proposal to build a starshade for the Webb telescope, and concludes that the surprise shown in the comic is not likely to occur in real life. NASA stopped this sponsorship in 2008, and the New Worlds Mission has been looking for additional financing since 2010. Telescope people refers to the engineers and scientists who build, operate, and use space telescopes. It seems clear that Randall would like to point attention to the New Worlds Mission, possibly hoping for increased funding for the project so a starshade could become a reality for the Webb telescope. That Randall is interested in exoplanets has been demonstrated many times in xkcd. Note that two of the Webb telescope's instruments , the NIRCam and the MIRI, feature starlight-blocking coronagraphs for observation of faint targets such as exoplanets, so the telescope has ways to improve the visibility of these planets. However, Randall (and the New Worlds Mission) believe that a starshade would be better suited for this task. The idea of an occulting telescope was used in 975: Occulting Telescope , where it turns out the purpose is to just block all star light, not to see exoplanets. [Megan and Ponytail are walking.] Megan: Space telescopes could see exoplanets better if they used free-floating opaque discs to block the stars' glare. [They stop walking in this zoom in on their heads. Ponytail has turned towards Megan.] Megan: They thought about including one with the Webb telescope, but cut it to save money. Ponytail: Well... does it have to be their disc? [In this frame-less panel Megan is left standing as Ponytail turns and walks away.] Megan: What do you mean? Ponytail: Like, if I Kickstart a starshade for them? Megan: Um. Would you at least warn them? Ponytail: Eh. Whatever. [Cueball and Hairbun, both wearing headsets, are sitting on one legged stools on either side of a slim desk with two computers screens on top of it. Each are looking at their own screens while typing on a keyboard in front of them. Hairbun is pointing at her screen. A small frame is overlaid on the top of the panels frame with a caption:] NASA, 2018: Cueball: Initiating Webb calibrat- Cueball: Aaaaa ! What the hell is that!? Hairbun: Hey, look, exoplanets!

Wrong

Wrong

https://www.xkcd.com/1731

https://www.explainxkcd.com/wiki/index.php/1731:_Wrong

[White Hat is walking beside Megan, index finger extended] White Hat: Really, we're all made of antimatter. A proton consists of two quarks and an antiquark. Megan: ...I don't think that's right. [White Hat stops to take out his smartphone tapping on it. Megan stops and turns towards him.] White Hat: Sure it is. Neutrons are, too. Megan: Do you mean "up" and "down" quarks? I think antiquarks are a different thing. White Hat: No, let me show you... Tap Tap [Zooming in on White Hat's head, while he is holding his phone up looking at it. He is thinking as shown with a bubbly thought bubble.] White Hat (thinking): I'm...wrong? [White Hat has lowered the phone. He is still thinking the same but the text has been scribbled out.] White Hat (thinking): I'm...wrong? [White Hat purges the thought from his mind] White Hat (thinking): ... [Similar setting as in the first panel, but in a full row wide panel, and White Hat is still holding his smartphone] White Hat: Really, the whole idea of "particles" is inaccurate. These are abstractions arising from quantum field theory, but what most people don't realize is... Megan: *Sigh*

All matter that we encounter in everyday life is normal matter and not antimatter . Atoms, while once when they were named believed to be the smallest unit of matter, are now known to be made up of protons , neutrons and electrons . Protons and neutrons are in turn made up of quarks , which are fundamental particles (meaning not made of other particles). Quarks come in six different " flavours " (up, down, top, bottom, charm, and strange), with protons and neutrons being made of up and down quarks. Each flavour also has a corresponding antiparticle , an antiquark, which would make up antiprotons and antineutrons. White Hat and Megan appear to be discussing the topics of antimatter and subatomic particles. White Hat makes the assertion that we (referring to people and objects) are made partially of antimatter, because, as he claims, a proton (one of the particles which make up all matter) is made of two quarks and an antiquark. In fact, protons are made up of two up quarks and a down quark, which are all not antiquarks. He is likely making the mistake of mixing up the "up" and "down" flavours of quarks (which can be seen as complementary flavours of quarks) and mistaking them to be mutual antiparticles. He continues to elaborate on his idea by mentioning neutrons, which are made of two down quarks and an up quark. When Megan (accurately) doubts his claim, White Hat takes out his smartphone to look it up, in order to show Megan that he is correct. However, upon researching online, he realizes that he was, in fact, wrong (hence the title of the comic). Not wanting to admit being incorrect or yield his position in the discussion, he convinces himself that he wasn't actually wrong, as depicted by his mentally erasing the realization that he was wrong. Instead, he completely changes the topic to try and re-frame it so that he is not wrong. In this case, he circles back and criticizes the entire scientific concept of "particles", which can be seen as an attempt at a straw man on his part. Presumably, he will go on to explain how humans are not made of particles and quarks, but of waves. It is rather common to be unwilling to admit fault (the whole topic of this comic) and to instead try to maintain an air of infallibility and intelligence. Some people are just too prideful to admit that they are inherently fallible. White Hat is one of those people, as depicted in several of his earlier appearances (see trivia section ). Randall uses this comic to criticize people who are unable to put aside their ego and re-assess what they know in the face of empirical data. Such thinking flies directly against scientific rigor (adding an extra layer of irony to the situation, since White Hat and Megan are discussing a scientific topic). This method had already been called wrong in 803: Airfoil . White Hat's new topic, where he can be right, includes the quantum field theory , a very complicated field, which it is likely one Megan is not well versed in (inferred by the fact that she was not quite sure about the anti-quarks). So he may be raising the topic because he believes she will not understand it sufficiently to refute his correctness. Megan, however, recognizes exactly what he is trying to do, and can only sigh in response to his failed efforts. In the QFT, particles are often described as resonances or excited states of the underlying physical field, in the same way as photons may be thought of as excitations in the electromagnetic field; in this way White Hat appears to be dismissing his earlier errors by implying that particles are merely an effect of something more complex, of which he can demonstrate his knowledge. Furthermore, in quantum field theory quarks do not exist in the conventional sense. In the title text, White Hat just remembers another thing he's right about. This demonstrates even more clearly that he is not interested in a discussion on the merits of a topic, but instead is seeking only recognition and validation for being right. This bears some similarity to 386: Duty Calls , in which Cueball stays up late correcting someone on the Internet, and 2051: Bad Opinions , where Cueball actively seeks out people with bad opinions for him to correct. White Hat may have incorrectly remembered that, while the valence quarks in a proton are all matter, quantum field theory says that protons also contain an indefinite number of "virtual" anti-quarks, quarks, and gluons. See this video What are Quarks? about this. His final comment could be referring to the ontological debate over whether virtual particles are in some sense real or only an artefact of perturbation theory. Alternatively, he may have been confused by the fact that negatively charged quarks contribute negatively to baryon number. <!-- I think that that's incorrect; could you be thinking about strangeness and bottomness instead? I'm not wrong, but let's talk about something else that I'm right about instead. --> [White Hat is walking beside Megan, index finger extended] White Hat: Really, we're all made of antimatter. A proton consists of two quarks and an antiquark. Megan: ...I don't think that's right. [White Hat stops to take out his smartphone tapping on it. Megan stops and turns towards him.] White Hat: Sure it is. Neutrons are, too. Megan: Do you mean "up" and "down" quarks? I think antiquarks are a different thing. White Hat: No, let me show you... Tap Tap [Zooming in on White Hat's head, while he is holding his phone up looking at it. He is thinking as shown with a bubbly thought bubble.] White Hat (thinking): I'm...wrong? [White Hat has lowered the phone. He is still thinking the same but the text has been scribbled out.] White Hat (thinking): I'm...wrong? [White Hat purges the thought from his mind] White Hat (thinking): ... [Similar setting as in the first panel, but in a full row wide panel, and White Hat is still holding his smartphone] White Hat: Really, the whole idea of "particles" is inaccurate. These are abstractions arising from quantum field theory, but what most people don't realize is... Megan: *Sigh*

Earth Temperature Timeline

Earth Temperature Timeline

https://www.xkcd.com/1732

https://www.explainxkcd.com/wiki/index.php/1732:_Earth_Temperature_Timeline

Note there are several spelling errors in the comic, so please do only correct spelling errors that are not part of the comic! See more in the trivia section . [A large heading, followed by a sub-caption. Below that two lines with a statement in between:] A timeline of Earth’s average temperature since the last ice age glaciation When people say “The climate has changed before,” these are the kinds of changes they’re talking about. [A very long chart below the headings above is headed with a label for the scale of the X-axis above the chart. Below that a sub-caption. To the left an arrow down to the top of the chart pointing to the dotted curves starting point (at -4.3°C below the 1961-1990 average) with a label above the arrow. And arrow pointing left to the left of the center and another pointing right to the right of the center has labels. Below these is the temperature scale of the X-axis, with 9 ticks between the borders each with a label ranging from -4 to +4°C compared to the 1961-1990 average, but with another step in each direction not labeled towards to axis so the chart covers -5 to +5°C compared to the 1961-1990 average.] Temperature Compared to the 1961-1990 average Start Colder Warmer -4°C -3°C -2°C -1°C 0°C +1°C +2°C +3°C +4°C [To the right of the chart is a gray text standing on the side down along the outer boarder of the chart with the sources for the chart:] Source: Shakun et. al. (2012) , Marcott et. al. (2013), Annan and Hargreaves (2013) , HadCRUT 4 , IPCC [The chart is split in 10 columns by the temperature scale and the borders. The two central columns are white, and then from there to the left the background becomes a faded color that changes from light blue to blue at the edge in four steps. Similarly to the right the color changes from light red to red. To the left there is a time scale taking 500 years leaps from 20,000 BCE all the way to year 1, where there are two years, one for BBC and one for CE. The 500 year leaps continue until 1500 CE and from there the steps are down to 100 years until 2100 with also present day 2016 labeled. After 1500 the CE is omitted. The labels stop there, but there is space below covering down to 2200 CE. There is clearly visible division line across the chart on the level of each of the 500 step, and fainter lines for each of the 100 steps all the way even though only the last 5 of these 100 steps are labeled. There is a similar clear line at 2016. Below each step on the Y-axis is noted, and then any text starting before the next step is noted below indented. If there are extra image belonging to text this is indented once more. The graph that the whole chart is about is a dotted line that begins at the “start” point mentioned above at -4.3°C and then begins to go straight down. It will change left and right all the way down. To being with all text and most drawings are to right of the dotted curve. Whenever something is to the left it will be noted. When it says to the left above something, and then nothing over the next, then the next will be to the right. Only at the very bottom are there more entries to the left than right. ] 20000 BCE [An arrow goes from the dotted line to the central line at 0°C. In the middle of the line there is a temperature label:] 4.3°C At the start of our timeline, 22,000 years ago, Earth is 4°C colder than during the late 20 th century. Boston is buried under almost a mile of ice, and the glaciers reach as far south as New York City. [The Statue of Liberty is shown in front of a glacier front. A very tiny Cueball is on top of the glacier. The drawing is labeled and so is also the glacier.] New York Ice [Cueball (wearing a knit cap with a pom-pom is seen walking in a snowy landscape leaving black footprints behind him. He walks through the white central part of the chart.] [The skyline of Boston is shown with two clear buildings among all the other. Above it is a line and in between this area has been filled with thin lines. The drawing is labeled and so is this area. Also the skyline has an arrow pointing at it with a label:] Boston Ice Modern skyline 19500 BCE But the world is about to warm up. By this time, humans have already spread across Africa, Eurasia, and Australia. They’ve created painting, pottery, rope, and bows and arrows, but haven’t developed writing or farming. 19000 BCE Changes in the Earth’s orbit mean that more sunlight reaches the polar ice… [A line chart with a labeled Y-axis with three labeled ticks. The curve starts up and then goes down five times and up four times ending down. There is one plateau towards the end compared to the rest of the curve where the ups and downs are quite alike.] Summer sun W/m 2 at 60°N 550 500 450 18500 BCE [A map of the world. At the top is a light gray area covering North America, Greenland and northern Europe and most of the northern part of Russia. A similar gray area covers Antarctica. There are two labels in the gray area above and one in the gray area below:] Ice Ice Ice 18000 BCE …And the ice sheets start to melt. 17500 BCE Temperatures have been creeping upward, but around this point, CO 2 levels start to climb… 17000 BCE …And then the warming speeds up. 16500 BCE [Cueball is standing with a spear just the right of the graph talking to a rabbit.] Cueball: Still pretty cold. 16000 BCE [Megan points to the graph to the right of her and between her and Ponytail standing on the other side. Mean is the first drawing on the left side of the dotted curve, which has hardly moved since the beginning, only to just on the other side of 4°C.] [In the right part of the chart is an explanation of the data. Below the first two lines there are four drawings each showing possible temperature swings in reality compared to the smoothed data that represents the dotted curve of the entire chart. The dotted curve is shown in all four drawings and a thin line is shown running along it but with much more fluctuation left and right on the first two, a large spike right on the third and a large bump way right on the fourth. Above these there are two labels. The first labels is inside a bracket that covers the first three, and the last label is for the last drawing. Below is a list of sources.] Limits of this data: Short warming or cooling spikes might be “smoothed out” by these reconstructions but only if they’re small or brief enough. Possible Unlikely Reconstructions are from Shakun (2012) and Marcott (2013), scaled to Annan + Hargreaves (2013) estimate for the last glacial period. 15500 BCE In what is now France, humans paint murals on the walls of the Lascaux caves [Hairy paints three animals, two with horns, and two humans, Cueball holding hand with Hairy who has a spear. On the other side of the central line Megan writes three letters, the last of which is reversed.] NIИ 15000 BCE Ice sheets around Alaska shrink, exposing a land bridge between Asia and North America [From around the bottom if this section and down to 11500 BCE the dotted curve moved steadily to the right towards warmed temperature peaking close to -1.5°C. Before this the temperature had not moved much away from that at the start.] 14500 BCE [Cueball walks right looking back at the graph behind him. Megan walks in front of him pointing further right.] Cueball: Cool. Humans reach North America. 14000 BCE The edge of the ice withdraws from New York City and retreats North. [A large glacier front speaks in a speech bubble with an arrow pointing at it. Behind is there are four peaks in the horizon and in front of it three small melting pools and some rocks on the ground.] Glacier: That’s it! I’m moving to Canada! 13500 BCE Humans domesticate dogs (Date uncertain, may be much earlier) [Megan and Cueball is watching a wolf looking at them.] Megan: Okay, you can live in our homes and we’ll feed you, but we’ll still get mad f you poop on the floor. Wolf: Deal. Cueball: And we get to breed you to be tiny and dress you in little costumes. Wolf: …Wait. 13000 BCE [Randall did not use the normal spelling for Woolly Rhino, but this is an accepted alternative spelling:] Wooly Rhino goes extinct Oregon is scoured by huge floods as glacial dams burst and lakes of meltwater flow to the sea 12500 BCE Ice sheets withdraw from Chicago 12000 BCE Humans settle Abu Hureyra in Syria 11500 BCE [An arrow on the left side of the dotted curve is pointing down along the dotted curve and to the left indicate temperature is declining again, meaning the dotted curve now moves left to colder temperatures. This only continues until 10500 BCE. It is only the second time something is noted on the left side after Megan at 16000 BCE] Temperatures start to decline, mainly in the Northern hemisphere This may be caused by changes in ocean circulation due to the floods of cold fresh meltwater flowing into the Atlantic as the North American ice sheet melts. This cooler period is called the Younger Dryas 11000 BCE [This is the first text to the left of the dotted curve:] Humans reach Argentina 10500 BCE [An arrow pointing down along the right side of the dotted curve and to the right indicate temperature is increasing again, meaning the dotted curve now moves right to hotter temperatures. This continues until 8000 BCE where it levels out just above 0°C.] Warming resumes Human settlements at Jericho 10000 BCE First development of farming 9500 BCE Saber-toothed cat goes extinct [To the left:] Horses disappear from North America 9000 BCE [To the left, Randall spelled Pokémon wrong:] Last North American Pokemon go extinct [Cueball with a speak and Megan is looking up at this last “fact”.] Megan: That is not a real fact. Temperatures reach modern levels Rising seas cut off the land bridge between North America and Asia Cattle domesticated 8500 BCE Ice sheets retreat across the Canadian border Temperatures start to level out slightly above 1961-1990 levels 8000 BCE [The above sentence breaks over the 8000 BCE line. From here a maximum in temperature on the chart is reached at 0.5°C which will not be overtaken until 2000 CE. It stays almost constant here until 5000 BCE where a slight cooling begins.] 7500 BCE [To the left:] This warm, stable period is called the Holocene Climate Optimum [To the left:] Jiahu settled in China 7000 BCE Final collapse of the North American ice sheet leads to rapid 2-4m sea level rise… [A small arrow points down and left to the right of the dotted curve. There is a small decrease in temperature but it is very small and would have been missed without the arrow and label.] …And a period of cooling in the Northern hemisphere 6500 BCE [To the left:] As seas rise to near their modern levels, Britain is cut off from mainland Europe 6000 BCE Humans develop copper metalworking 5500 BCE [To the left:] Massive volcanic eruption in Oregon creates crater lake Gold metalworking 5000 BCE [To the left:] Invention of the wheel [To the left. To the right of the dotted curve is an arrow pointing down and slightly left. From here temperature decreases very slowly but steadily from 0.5°C until 1000 BCE where a stable plateau is reached around 0°C.] Earth begins to cool slowly mainly due to regular cycles in its orbit 4500 BCE [To the left:] Proto-Indo-European language develops [To the right of the curve Ponytail holds up a hand towards Cueball.] Ponytail: Let’s make our language heavily inflected, so future students have to memorize a zillion verb endings! Cueball: Okay! [To the left:] Permanent settlements in the fertile crescent 4000 BCE Horses domesticated [To the left:] Minoan culture arises on Crete 3500 BCE Egyptian mummification Rise of the Indus Valley civilization [To the left:] Invention of writing in Sumer “prehistory” ends, “history” begins Earliest human whose name we know (Pharaoh Iry-Hor in Egypt) 3000 BCE Three Sovereigns and five emperors period in China Gilgamesh [To the left:] Imhotep Mayan culture emerges [To the left:] Great Pyramid constructed 2500 BCE Corded Ware culture in Europe [To the left of the curve two rock musicians with long hair and electrical guitars are standing on either side of a small gate made of three slabs of stone, one on top of the other two standing stones.] Stonehenge completed Chariots developed 2000 BCE [To the left:] Alphabetic writing developed in Egypt Last mammoths on a tiny Siberian island go extinct [To the left:] Minoan eruption 1500 BCE [To the left:] Iron smelting Olmec civilization develops in Central America [A Trojan horse with two Cueball-like guys in front and a third standing on its back. Its back is at three Cueball’s height and its head rises to the level of the Cueball on its back. It stands on a platform with four wheel on the visible side. There is text on the horse] Setting of the Iliad and the Odyssey Text on horse: Not a trap [To the left:] Invasion of the Sea peoples* * A real thing Polynesians explore the Pacific Ocean 1000 BCE [From 1000 BBC to 1000 CE the temperature is stable and very close to 0°C.] [To the left:] Solomon Illiad [sic] and Odyssey composed [To the left:] Rise of Greek city-states Neo-Assyrian empire [To the left:] First Olympics Zapotec writing in modern Mexico [To the left:] Confucius 500 BCE [To the left:] The stuff in the 300 (film)|movie 300 , but regular speed and with more clothing Buddha Nazca Lines [To the left:] Alexander the Great [To the left:] Mayan hieroglyphics Ashoka the Great [To the left:] Paper invented [To the left:] Asterix Teotihuacán metropolis [To the left:] Julius Caesar [At the year 0, there is instead two numbers for each of the two scales before and after Christ:] 1 BCE 1 CE [To the left:] Roman Empire Jesus [To the left and erupting volcano.] Pompeii Three Kingdoms period [To the left:] Gupta empire [To the left:] Various groups take turns sacking Rome Attila the Hun 500 CE Muhammad [To the left:] Tang Dynasty [An arrow to the right of the dotted curve pointing down, takes a swing far out from the curve and then bends back again. The text label next to it breaks into the next 500 period. The dotted curve stays stable at 0°C along this arrow.] Medieval warm period in Europe and some northern regions (too regional to affect the global average much) [To the left:] Leif Eriksson 1000 CE [The dotted curve moves to the left towards lower temperature reaching a minimum around 1650 of about -0.6°C at the Little Ice Age.] [To the left a drawing of a compass with needle pointing the black end towards north east. There are labels for the four main directions and a label next to it:] N W E S Magnetic compass navigation [To the left:] Ghengis [sic] Khan Zheng He’s fleet explores Asia and Africa [To the left:] Aztec Alliance [To the left:] Printing press [To the left:] Columbus 1500 CE European Renaissance [To the left:] Shakespeare 1600 [To the left:] Newton [To the right of the dotted curve there is an arrow pointing down that makes a swing in towards the curve and then back out again. At -0.6°C this is the coldest it has been since 9500 BCE. It is labeled:] ”Little Ice Age” 1700 Steam engines [To the left:] Unites States Independence 1800 Industrial Revolution [To the left:] Telegraphs [After this the dotted curve becomes solid.] 1900 [To the left, and on the line for 1900:] Airplanes [To the left:] World Wars [The solid line takes a step to the right close to 0°C. Over the rest of the 1900s it moves closer to 0°C crossing it before 2000 where it almost reaches the maximum temperature of 0.5 °C from earlier in 8000 BCE.] Fossil fuel CO 2 emissions start rapidly increasing [To the left:] Nuclear weapons [To the left:] Internet 2000 Northwest Passage opens [From here to present day the solid line increases rapidly and in 2016 present day is almost reaches 1°C, with about 0.8°C.] 2016 [To the left on the line for 2016:] Present day [From here the curve once again becomes dotted as this is the future. After one dot it splits in two and after the first two dots another split between them occurs forming three possible future dotted curves. The first curve bending down before the others, and thus to the right of the other two reaches about 1.2°C and then goes straight down and stops at the 2100 line. An arrow points to it from the left and a label is written patly before and the rest after the 2100 line to the left of the curve:] Best-case scenario assuming immediate massive action to limit emissions 2100 [The middle curve bends a little down after reaching 1.3°C and then continues this path reaching 2°C in 2100. An arrow point from below to it and a label is written below the curve and below 2100 line:] Optimistic scenario [The last line continues along the path from the last 16 years of the solid line reaching 4.2°C at 2100, almost as far on the other side of 0°C in 150 years as it took 14000 years to move from the other side from the start of the chart. Another arrow point to this from below with a label below the curve and below 2100 line:] Current Path This comic became popular with a much broader audience than most xkcd comics. It was discussed admiringly by news sites such as Popular Science , Reason , Slate , Smithsonian , Forbes , Vox , NPR , Quartz , Science Alert and Climate Central . It was promoted by famous individuals such as Elon Musk and even twitted by the UN council on Climate Change , and obviously hated on by vocal climate change deniers and cranks such as Anthony Watts debunked and Joanne Nova debunked Saying the "dotted line comes from computer models" is a bit inaccurate. Prehistoric temperature reconstructions are based on lots of measurements from lots of places around the planet: ice cores, lake and ocean sediments, etc. which are the best proxy records of climate change. From those measurements, one infers temperature, so Randall Munroe may be more correct than he realises . Calling that process computer modeling stretches the meaning of the phrase. For more rationalist critique of this chart not driven by the agenda of pushing pseudoscientific beliefs which are against the worldwide consensus, see t h i s and most insightfully, this . Note: Since a lot of new people are here looking for this chart today, I'll be posting Wednesday's comic on Thursday instead. Before that, the normal heading with the release day of xkcd was shown. This was (of course) still there Tuesday the day after the release, because it was first on Wednesday there were reason to note the delay. It stayed in place even for some time after the "Wednesday" comic was released on Thursday, but was then removed before noon (EST) on Thursday. Randall did thus not post a link to this comic in the header text for new visitors to use, only giving them that one extra day. Even though the next comic was released on a Thursday, the scheduled Friday comic 1734: Reductionism was still released as planned. This was also the first time this occurred on xkcd - see this trivia item from the Friday comic.

This comic is a timeline on how the temperature has changed from 20,000 BCE (Before Common Era ) to the present day (2016), with three predictions for the rest of the 21st century depending on what actions are taken (or not taken) to stop CO₂ emission. This comic is a direct, but much more thorough, follow up on the previous global warming comic: 1379: 4.5 Degrees . By having readers scroll through millennia of slow-paced natural changes, Randall uses the comic to confront the rapid temperature rise in recent years. Over the past 100 years, human action has produced a large amount of CO₂ emissions , which have caused a rise in average global temperature through the greenhouse effect . This is called global warming and is part of a climate change , a subject that has become a recurrent subject on xkcd. There are still many people who claim that this is not happening, or at least that it is not caused by any human actions, called climate change deniers . One argument of theirs is that global warming is happening for natural causes, summarized with the phrase "temperature has changed before". This comic shows that while temperature changes have indeed occurred before, the speed of the current temperature rise is much, much faster than those measured for many previous thousands of years. The comic became so popular that Randall postponed the release of his next comic to keep this one on the front page one day longer. The temperature curve is a dotted line most of the time, but from about 1850 to 2016 the measurement data is good enough to let the curve become a solid line indicating that this is not an estimate. Before 1850 the temperature is an estimate based on the sources given. And likewise into the future the three possible curves are also dotted to show that they are predictions, based on how seriously the population of Earth takes knowledge (and comics) like this. Although this is a topic Randall obviously takes very seriously, and by far most of the facts fit with known history, he still includes several jokes in the comic . See also the table explaining each item in the comic. After the election of Donald Trump for president later the year of this comic's release, it is possible that Randall believes that his worst fears (as expressed by the current path at the bottom) will hold up, with the actions taken by the new president. The title text compares the saying that "the temperature has changed before" comparing temperature changes over thousands of years to the rapid global warming over the last century with saying that the "small" changes to the temperature a car experiences over the years of normal usage should not make you worried over the rapid temperature increase that happens when someone sets your car on fire. Randall previously used this joke in 1693: Oxidation . The image attributes climate data sources as "Shakun et al. (2012), Marcott et al. (2013), Annan and Hargreaves (2013), HadCRUT4, IPCC": Note there are several spelling errors in the comic, so please do only correct spelling errors that are not part of the comic! See more in the trivia section . [A large heading, followed by a sub-caption. Below that two lines with a statement in between:] A timeline of Earth’s average temperature since the last ice age glaciation When people say “The climate has changed before,” these are the kinds of changes they’re talking about. [A very long chart below the headings above is headed with a label for the scale of the X-axis above the chart. Below that a sub-caption. To the left an arrow down to the top of the chart pointing to the dotted curves starting point (at -4.3°C below the 1961-1990 average) with a label above the arrow. And arrow pointing left to the left of the center and another pointing right to the right of the center has labels. Below these is the temperature scale of the X-axis, with 9 ticks between the borders each with a label ranging from -4 to +4°C compared to the 1961-1990 average, but with another step in each direction not labeled towards to axis so the chart covers -5 to +5°C compared to the 1961-1990 average.] Temperature Compared to the 1961-1990 average Start Colder Warmer -4°C -3°C -2°C -1°C 0°C +1°C +2°C +3°C +4°C [To the right of the chart is a gray text standing on the side down along the outer boarder of the chart with the sources for the chart:] Source: Shakun et. al. (2012) , Marcott et. al. (2013), Annan and Hargreaves (2013) , HadCRUT 4 , IPCC [The chart is split in 10 columns by the temperature scale and the borders. The two central columns are white, and then from there to the left the background becomes a faded color that changes from light blue to blue at the edge in four steps. Similarly to the right the color changes from light red to red. To the left there is a time scale taking 500 years leaps from 20,000 BCE all the way to year 1, where there are two years, one for BBC and one for CE. The 500 year leaps continue until 1500 CE and from there the steps are down to 100 years until 2100 with also present day 2016 labeled. After 1500 the CE is omitted. The labels stop there, but there is space below covering down to 2200 CE. There is clearly visible division line across the chart on the level of each of the 500 step, and fainter lines for each of the 100 steps all the way even though only the last 5 of these 100 steps are labeled. There is a similar clear line at 2016. Below each step on the Y-axis is noted, and then any text starting before the next step is noted below indented. If there are extra image belonging to text this is indented once more. The graph that the whole chart is about is a dotted line that begins at the “start” point mentioned above at -4.3°C and then begins to go straight down. It will change left and right all the way down. To being with all text and most drawings are to right of the dotted curve. Whenever something is to the left it will be noted. When it says to the left above something, and then nothing over the next, then the next will be to the right. Only at the very bottom are there more entries to the left than right. ] 20000 BCE [An arrow goes from the dotted line to the central line at 0°C. In the middle of the line there is a temperature label:] 4.3°C At the start of our timeline, 22,000 years ago, Earth is 4°C colder than during the late 20 th century. Boston is buried under almost a mile of ice, and the glaciers reach as far south as New York City. [The Statue of Liberty is shown in front of a glacier front. A very tiny Cueball is on top of the glacier. The drawing is labeled and so is also the glacier.] New York Ice [Cueball (wearing a knit cap with a pom-pom is seen walking in a snowy landscape leaving black footprints behind him. He walks through the white central part of the chart.] [The skyline of Boston is shown with two clear buildings among all the other. Above it is a line and in between this area has been filled with thin lines. The drawing is labeled and so is this area. Also the skyline has an arrow pointing at it with a label:] Boston Ice Modern skyline 19500 BCE But the world is about to warm up. By this time, humans have already spread across Africa, Eurasia, and Australia. They’ve created painting, pottery, rope, and bows and arrows, but haven’t developed writing or farming. 19000 BCE Changes in the Earth’s orbit mean that more sunlight reaches the polar ice… [A line chart with a labeled Y-axis with three labeled ticks. The curve starts up and then goes down five times and up four times ending down. There is one plateau towards the end compared to the rest of the curve where the ups and downs are quite alike.] Summer sun W/m 2 at 60°N 550 500 450 18500 BCE [A map of the world. At the top is a light gray area covering North America, Greenland and northern Europe and most of the northern part of Russia. A similar gray area covers Antarctica. There are two labels in the gray area above and one in the gray area below:] Ice Ice Ice 18000 BCE …And the ice sheets start to melt. 17500 BCE Temperatures have been creeping upward, but around this point, CO 2 levels start to climb… 17000 BCE …And then the warming speeds up. 16500 BCE [Cueball is standing with a spear just the right of the graph talking to a rabbit.] Cueball: Still pretty cold. 16000 BCE [Megan points to the graph to the right of her and between her and Ponytail standing on the other side. Mean is the first drawing on the left side of the dotted curve, which has hardly moved since the beginning, only to just on the other side of 4°C.] [In the right part of the chart is an explanation of the data. Below the first two lines there are four drawings each showing possible temperature swings in reality compared to the smoothed data that represents the dotted curve of the entire chart. The dotted curve is shown in all four drawings and a thin line is shown running along it but with much more fluctuation left and right on the first two, a large spike right on the third and a large bump way right on the fourth. Above these there are two labels. The first labels is inside a bracket that covers the first three, and the last label is for the last drawing. Below is a list of sources.] Limits of this data: Short warming or cooling spikes might be “smoothed out” by these reconstructions but only if they’re small or brief enough. Possible Unlikely Reconstructions are from Shakun (2012) and Marcott (2013), scaled to Annan + Hargreaves (2013) estimate for the last glacial period. 15500 BCE In what is now France, humans paint murals on the walls of the Lascaux caves [Hairy paints three animals, two with horns, and two humans, Cueball holding hand with Hairy who has a spear. On the other side of the central line Megan writes three letters, the last of which is reversed.] NIИ 15000 BCE Ice sheets around Alaska shrink, exposing a land bridge between Asia and North America [From around the bottom if this section and down to 11500 BCE the dotted curve moved steadily to the right towards warmed temperature peaking close to -1.5°C. Before this the temperature had not moved much away from that at the start.] 14500 BCE [Cueball walks right looking back at the graph behind him. Megan walks in front of him pointing further right.] Cueball: Cool. Humans reach North America. 14000 BCE The edge of the ice withdraws from New York City and retreats North. [A large glacier front speaks in a speech bubble with an arrow pointing at it. Behind is there are four peaks in the horizon and in front of it three small melting pools and some rocks on the ground.] Glacier: That’s it! I’m moving to Canada! 13500 BCE Humans domesticate dogs (Date uncertain, may be much earlier) [Megan and Cueball is watching a wolf looking at them.] Megan: Okay, you can live in our homes and we’ll feed you, but we’ll still get mad f you poop on the floor. Wolf: Deal. Cueball: And we get to breed you to be tiny and dress you in little costumes. Wolf: …Wait. 13000 BCE [Randall did not use the normal spelling for Woolly Rhino, but this is an accepted alternative spelling:] Wooly Rhino goes extinct Oregon is scoured by huge floods as glacial dams burst and lakes of meltwater flow to the sea 12500 BCE Ice sheets withdraw from Chicago 12000 BCE Humans settle Abu Hureyra in Syria 11500 BCE [An arrow on the left side of the dotted curve is pointing down along the dotted curve and to the left indicate temperature is declining again, meaning the dotted curve now moves left to colder temperatures. This only continues until 10500 BCE. It is only the second time something is noted on the left side after Megan at 16000 BCE] Temperatures start to decline, mainly in the Northern hemisphere This may be caused by changes in ocean circulation due to the floods of cold fresh meltwater flowing into the Atlantic as the North American ice sheet melts. This cooler period is called the Younger Dryas 11000 BCE [This is the first text to the left of the dotted curve:] Humans reach Argentina 10500 BCE [An arrow pointing down along the right side of the dotted curve and to the right indicate temperature is increasing again, meaning the dotted curve now moves right to hotter temperatures. This continues until 8000 BCE where it levels out just above 0°C.] Warming resumes Human settlements at Jericho 10000 BCE First development of farming 9500 BCE Saber-toothed cat goes extinct [To the left:] Horses disappear from North America 9000 BCE [To the left, Randall spelled Pokémon wrong:] Last North American Pokemon go extinct [Cueball with a speak and Megan is looking up at this last “fact”.] Megan: That is not a real fact. Temperatures reach modern levels Rising seas cut off the land bridge between North America and Asia Cattle domesticated 8500 BCE Ice sheets retreat across the Canadian border Temperatures start to level out slightly above 1961-1990 levels 8000 BCE [The above sentence breaks over the 8000 BCE line. From here a maximum in temperature on the chart is reached at 0.5°C which will not be overtaken until 2000 CE. It stays almost constant here until 5000 BCE where a slight cooling begins.] 7500 BCE [To the left:] This warm, stable period is called the Holocene Climate Optimum [To the left:] Jiahu settled in China 7000 BCE Final collapse of the North American ice sheet leads to rapid 2-4m sea level rise… [A small arrow points down and left to the right of the dotted curve. There is a small decrease in temperature but it is very small and would have been missed without the arrow and label.] …And a period of cooling in the Northern hemisphere 6500 BCE [To the left:] As seas rise to near their modern levels, Britain is cut off from mainland Europe 6000 BCE Humans develop copper metalworking 5500 BCE [To the left:] Massive volcanic eruption in Oregon creates crater lake Gold metalworking 5000 BCE [To the left:] Invention of the wheel [To the left. To the right of the dotted curve is an arrow pointing down and slightly left. From here temperature decreases very slowly but steadily from 0.5°C until 1000 BCE where a stable plateau is reached around 0°C.] Earth begins to cool slowly mainly due to regular cycles in its orbit 4500 BCE [To the left:] Proto-Indo-European language develops [To the right of the curve Ponytail holds up a hand towards Cueball.] Ponytail: Let’s make our language heavily inflected, so future students have to memorize a zillion verb endings! Cueball: Okay! [To the left:] Permanent settlements in the fertile crescent 4000 BCE Horses domesticated [To the left:] Minoan culture arises on Crete 3500 BCE Egyptian mummification Rise of the Indus Valley civilization [To the left:] Invention of writing in Sumer “prehistory” ends, “history” begins Earliest human whose name we know (Pharaoh Iry-Hor in Egypt) 3000 BCE Three Sovereigns and five emperors period in China Gilgamesh [To the left:] Imhotep Mayan culture emerges [To the left:] Great Pyramid constructed 2500 BCE Corded Ware culture in Europe [To the left of the curve two rock musicians with long hair and electrical guitars are standing on either side of a small gate made of three slabs of stone, one on top of the other two standing stones.] Stonehenge completed Chariots developed 2000 BCE [To the left:] Alphabetic writing developed in Egypt Last mammoths on a tiny Siberian island go extinct [To the left:] Minoan eruption 1500 BCE [To the left:] Iron smelting Olmec civilization develops in Central America [A Trojan horse with two Cueball-like guys in front and a third standing on its back. Its back is at three Cueball’s height and its head rises to the level of the Cueball on its back. It stands on a platform with four wheel on the visible side. There is text on the horse] Setting of the Iliad and the Odyssey Text on horse: Not a trap [To the left:] Invasion of the Sea peoples* * A real thing Polynesians explore the Pacific Ocean 1000 BCE [From 1000 BBC to 1000 CE the temperature is stable and very close to 0°C.] [To the left:] Solomon Illiad [sic] and Odyssey composed [To the left:] Rise of Greek city-states Neo-Assyrian empire [To the left:] First Olympics Zapotec writing in modern Mexico [To the left:] Confucius 500 BCE [To the left:] The stuff in the 300 (film)|movie 300 , but regular speed and with more clothing Buddha Nazca Lines [To the left:] Alexander the Great [To the left:] Mayan hieroglyphics Ashoka the Great [To the left:] Paper invented [To the left:] Asterix Teotihuacán metropolis [To the left:] Julius Caesar [At the year 0, there is instead two numbers for each of the two scales before and after Christ:] 1 BCE 1 CE [To the left:] Roman Empire Jesus [To the left and erupting volcano.] Pompeii Three Kingdoms period [To the left:] Gupta empire [To the left:] Various groups take turns sacking Rome Attila the Hun 500 CE Muhammad [To the left:] Tang Dynasty [An arrow to the right of the dotted curve pointing down, takes a swing far out from the curve and then bends back again. The text label next to it breaks into the next 500 period. The dotted curve stays stable at 0°C along this arrow.] Medieval warm period in Europe and some northern regions (too regional to affect the global average much) [To the left:] Leif Eriksson 1000 CE [The dotted curve moves to the left towards lower temperature reaching a minimum around 1650 of about -0.6°C at the Little Ice Age.] [To the left a drawing of a compass with needle pointing the black end towards north east. There are labels for the four main directions and a label next to it:] N W E S Magnetic compass navigation [To the left:] Ghengis [sic] Khan Zheng He’s fleet explores Asia and Africa [To the left:] Aztec Alliance [To the left:] Printing press [To the left:] Columbus 1500 CE European Renaissance [To the left:] Shakespeare 1600 [To the left:] Newton [To the right of the dotted curve there is an arrow pointing down that makes a swing in towards the curve and then back out again. At -0.6°C this is the coldest it has been since 9500 BCE. It is labeled:] ”Little Ice Age” 1700 Steam engines [To the left:] Unites States Independence 1800 Industrial Revolution [To the left:] Telegraphs [After this the dotted curve becomes solid.] 1900 [To the left, and on the line for 1900:] Airplanes [To the left:] World Wars [The solid line takes a step to the right close to 0°C. Over the rest of the 1900s it moves closer to 0°C crossing it before 2000 where it almost reaches the maximum temperature of 0.5 °C from earlier in 8000 BCE.] Fossil fuel CO 2 emissions start rapidly increasing [To the left:] Nuclear weapons [To the left:] Internet 2000 Northwest Passage opens [From here to present day the solid line increases rapidly and in 2016 present day is almost reaches 1°C, with about 0.8°C.] 2016 [To the left on the line for 2016:] Present day [From here the curve once again becomes dotted as this is the future. After one dot it splits in two and after the first two dots another split between them occurs forming three possible future dotted curves. The first curve bending down before the others, and thus to the right of the other two reaches about 1.2°C and then goes straight down and stops at the 2100 line. An arrow points to it from the left and a label is written patly before and the rest after the 2100 line to the left of the curve:] Best-case scenario assuming immediate massive action to limit emissions 2100 [The middle curve bends a little down after reaching 1.3°C and then continues this path reaching 2°C in 2100. An arrow point from below to it and a label is written below the curve and below 2100 line:] Optimistic scenario [The last line continues along the path from the last 16 years of the solid line reaching 4.2°C at 2100, almost as far on the other side of 0°C in 150 years as it took 14000 years to move from the other side from the start of the chart. Another arrow point to this from below with a label below the curve and below 2100 line:] Current Path This comic became popular with a much broader audience than most xkcd comics. It was discussed admiringly by news sites such as Popular Science , Reason , Slate , Smithsonian , Forbes , Vox , NPR , Quartz , Science Alert and Climate Central . It was promoted by famous individuals such as Elon Musk and even twitted by the UN council on Climate Change , and obviously hated on by vocal climate change deniers and cranks such as Anthony Watts debunked and Joanne Nova debunked Saying the "dotted line comes from computer models" is a bit inaccurate. Prehistoric temperature reconstructions are based on lots of measurements from lots of places around the planet: ice cores, lake and ocean sediments, etc. which are the best proxy records of climate change. From those measurements, one infers temperature, so Randall Munroe may be more correct than he realises . Calling that process computer modeling stretches the meaning of the phrase. For more rationalist critique of this chart not driven by the agenda of pushing pseudoscientific beliefs which are against the worldwide consensus, see t h i s and most insightfully, this . Note: Since a lot of new people are here looking for this chart today, I'll be posting Wednesday's comic on Thursday instead. Before that, the normal heading with the release day of xkcd was shown. This was (of course) still there Tuesday the day after the release, because it was first on Wednesday there were reason to note the delay. It stayed in place even for some time after the "Wednesday" comic was released on Thursday, but was then removed before noon (EST) on Thursday. Randall did thus not post a link to this comic in the header text for new visitors to use, only giving them that one extra day. Even though the next comic was released on a Thursday, the scheduled Friday comic 1734: Reductionism was still released as planned. This was also the first time this occurred on xkcd - see this trivia item from the Friday comic.

Solar Spectrum

Solar Spectrum

https://www.xkcd.com/1733

https://www.explainxkcd.com/wiki/index.php/1733:_Solar_Spectrum

[A chart shows the visible colored spectrum of the sun from deep violet to deep red. Along the spectrum are shown 28 black spectral lines of different thickness. Above the chart is a caption:] The Sun's spectral lines [Above the chart there are four and below the chart there are two labels, each label has one or more arrows pointing to different black lines. The two that has only one arrow points to two close lines marking them both. Only 22 lines are labeled like this, the other 6 are not labeled. The labels in reading order, with the number of arrows noted behind in square brackets:] Calcium [3] Iron [5] Sodium [1] Oxygen [2] Hydrogen [3] Magnesium [1] Those giant sunglasses [5]

This comic's release day was postponed from the scheduled Wednesday release to a Thursday release because Randall noticed the extreme popularity of the previous comic on Monday: 1732: Earth Temperature Timeline . Randall even explained this in the header text; see this trivia item from the previous comic. This comic depicts the Fraunhofer lines , i.e. the spectral lines seen when sunlight is split in a spectrometer . These appear as black gaps in the rainbow of light, caused by light being absorbed by elements in the Sun . The frequencies of light that an atom absorbs depend on the exact arrangement of electron orbitals around it - because each element has a different pattern of orbitals, each one has a distinctive pattern in the absorption spectrum. The chart shows most of the main lines in the visible spectrum and identifies the elements linked to them. The image of the Fraunhofer lines from Wikipedia is shown below in the section with a table of these lines. Here it can be seen that all the lines that are labeled with elements are correctly labeled. Also all lines shown in the part of the spectrum included in the comic are included. Ten of the lines included are not labeled in the picture on Wikipedia (at least not with an element; two of the three "h" labels are not in the table on Wikipedia). Six of these also have no label in the comic. The other four lines' label Those giant sunglasses constitutes the joke of the comic. There seems to be only one clear error in the comic and that is the fifth line labeled Sunglasses, the middle of the lines, which is actually a Hydrogen line (C in the picture below). But the line next to it to the right is one of those not labeled in either picture and it seems likely that it was this line Randall meant to be a Sunglass line... All ten extra lines (including both the labeled and unlabeled ones) seem to correspond to the spectrum of silicon , and the joke then refers to the silicon dioxide (aka glass) used in the lenses of the Sun's sunglasses. Of course, this means that the glasses have been ionized and turned into plasma by the heat of the sun. The idea of a sun with sunglasses is a reference to pictures/clipart of the sun wearing sunglasses, often used to denote good weather. Randall has specifically used this picture in at least two what if? posts: In Into the Sun it is seen in the fourth image. The title text of that image even references the fact that those sunglasses will block the light to Earth: A partial solar eclipse is when the Earth moves across the part of the Sun blocked by its sunglasses. So this comic is a direct callback to this what if? post. In Black Hole Moon it is in the first image also including a banana as the mouth. Both the image and the title text of that image references the fact that those sunglasses will block (eclipse) some the light to Earth: Doctors warn that even sunglasses that block UVB will only protect you from the part of the Sun covered by them. There is another joke in drawing a sun with sunglasses because sunglasses are meant to protect your eyes from the sun, so what should they protect the Sun's eye from, Star light...? Also, any glasses worn by the sun, would they not become sun glasses? Transitions ® is a brand of photochromic lenses ; however, photochromic lenses are often referred to as "transition lenses", so the title text does not necessarily refer to the brand. Photochromic lenses are a type of plastic lens used in prescription spectacles that allow the lens to turn dark when exposed to UV light such as that found in sunlight. The sun choosing to get transition lens would prove a waste of money as the lenses would be permanently transitioned to be dark, so a pair of ordinary sunglasses would likely have proved more cost effective. (Always assuming they do not turn into plasma when getting close to the sun...) This is the official image for Fraunhofer lines (solar spectrum) on Wikipedia: The graph is a typical spectral lines chart, with a long rainbow band (from ultraviolet to the left to infrared on the right both colors appearing black as they are not visible.) The black lines in it, indicating the traces of different elements. Noe that the comic only covers the visible part of this spectrum. [A chart shows the visible colored spectrum of the sun from deep violet to deep red. Along the spectrum are shown 28 black spectral lines of different thickness. Above the chart is a caption:] The Sun's spectral lines [Above the chart there are four and below the chart there are two labels, each label has one or more arrows pointing to different black lines. The two that has only one arrow points to two close lines marking them both. Only 22 lines are labeled like this, the other 6 are not labeled. The labels in reading order, with the number of arrows noted behind in square brackets:] Calcium [3] Iron [5] Sodium [1] Oxygen [2] Hydrogen [3] Magnesium [1] Those giant sunglasses [5]

Reductionism

Reductionism

https://www.xkcd.com/1734

https://www.explainxkcd.com/wiki/index.php/1734:_Reductionism

[The comic represents an entry in a dictionary for a word. Unlike normal comics not only capital letters are used, and thus here the capitalization of the comic is also used in the transcript. The entry is cut off through the bottom of the fourth line by the bottom of the panel, but the last line is still readable.] REDUCTIONISM • n . 1. "R" is a letter with origins in the Egyptian hieroglyphics. "E" stands for a vowel sound normally represented by "I" until the 1500's. "D" is

Reductionism is an approach that seeks to understand the world by breaking problems into simpler pieces. This approach can disregard emergent properties which appear only from the individual parts working together. In this comic Randall shows the first part of a dictionary entry on the word Reductionism . In a real dictionary like Dictionary.com an entry with similar build up looks like this: Reductionism Noun 1. The theory that every complex phenomenon, especially in biology or psychology, can be explained by analyzing the simplest, most basic physical mechanisms that are in operation during the phenomenon. 2. The practice of simplifying a complex idea, issue, condition, or the like, especially to the point of minimizing, obscuring, or distorting it. In the comic the n refers to noun and the "1." indicate that this is the first of more than one entries about the word. The meta joke is that Randall is attempting to define the word Reductionism by taking the reductionist approach to its extreme. He thus breaks the word into its 12 individual letters explaining the origin of each individual letter, acting as if the word was nothing more than the "sum" of all its letters. In doing so he entirely fails to explain the actual meaning of the word. The entire entry number 1. could in principle have 12 phrases one for each of the letters R, E, D, U, C, T, I, O, N, I, S and M, but here only the first two for R and E are included, the third (D) only just starts when the entry is cut off at the bottom of the panel. It could be argued that the two I's could share one explanation, but as a reductionist you might not even notice that the I had already been explained. As it happens, every letter of the Latin alphabet (the writing system used by the English language and many other languages) is ultimately derived from Egyptian hieroglyphics , not just "R". But maybe the same sentence is used for all the consonants as the only word in the explanation for "D" is "is"; the same that starts the explanation for "R". The second letter that is explained is "E", a vowel . In modern English spelling, the letter "E" is used – alone or in combination – to represent a number of different vowel sounds (compare "gene", "bed", "crepe"). In the word "reductionism", the "E" can be pronounced as /ɪ/ ("riductionism"), /iː/ ("reeductionism") or /ə/ ("ruductionism"), depending on dialect and emphasis, but the comic is talking about the sound used to pronounce the letter itself, /iː/ ("long E"). It explains that this vowel sound was normally represented with the letter "I" until the 1500's. This is a reference to the Great Vowel Shift , a change in the pronunciation of many English vowels around that time. Before then, a word like "see" was pronounced /seː/ (approximately "seh", with no diphthong), while a word like "bite" was pronounced /biːt/ ("beet"). So in modern English pronunciation, the "long E" sound is the same as what the "long I" spelling used to represent. In the title text, two people are speaking. The first speaker has noticed that "physics people can be a little on the reductionist side". (Randall would consider himself a physicist). The presumed physicist then says that it is a ridiculous notion. He challenges the other to "Name ONE reductionist word I've ever said." But by claiming he is not a reductionist by focusing on the individual words (which, even/especially in the case of "reductionist", are never used solely by reductionists) he is asking for an impossible comparison to be made, when proof of reductionism is clearly an emergent property of a fuller sentences, if not whole discourses. By insisting on focusing only upon individual words in this manner the speaker likely proves themself a reductionist, in the very act of trying to refute this accusation. Reductionism has previously appeared deep down in 1416: Pixels . [The comic represents an entry in a dictionary for a word. Unlike normal comics not only capital letters are used, and thus here the capitalization of the comic is also used in the transcript. The entry is cut off through the bottom of the fourth line by the bottom of the panel, but the last line is still readable.] REDUCTIONISM • n . 1. "R" is a letter with origins in the Egyptian hieroglyphics. "E" stands for a vowel sound normally represented by "I" until the 1500's. "D" is

Fashion Police and Grammar Police

Fashion Police and Grammar Police

https://www.xkcd.com/1735

https://www.explainxkcd.com/wiki/index.php/1735:_Fashion_Police_and_Grammar_Police

[Beneath two headings to the left and right are shown two aggressive-looking groups of people with only the four people in the front clearly shown for each group. Behind them five other people can be seen, but they are not drawn with the same solid line and are only partly shown behind the first four, but legs from all five in each group can be seen along with some heads (all Cueball like) and arms etc. The front of the left group consist of Hairy holding a fist up towards left, Megan with her arms crossed in front of her chest, Cueball holding a sign, using both hands, straight up above his head and another Cueball-like guy to the right is holding up a broken branch in one hand toward right. The person behind this last person is shown to hold up his fist towards right like Hairy does to the left. The sign shows a Crocs shoe in a circle with a strike through it going above the Crocs from top left to bottom right. The front of the right group consist of Megan holding both her arms over her head hands folded into fist while looking towards left, Cueball holding a sign, using both hands, towards the right and up above Ponytails head, she is raising one hand in a fist to the left and finally a bald guy with glasses is brandishing a short sword in one hand toward right while holding his other hand palm up. The sign has three similar words written beneath each other.] Left: Fashion Police Right: Grammar Police Sign: Their They're There [Below the two groups are eight points with bullets:] Judgemental and smug Angry about something deeply arbitrary Strong opinions backed by style guides Appreciate that the way that you are interpreted is your responsibility Understand that there's no way to "opt out" of sending messages by how you present yourself, and attempts to do so send strong messages of their own To seem cool and casual, pretend to ignore them while understanding them very well Vindictive about things that are often uncomfortably transparent proxies for race or social class Fun to cheer on until one of them disagrees with you [Caption below the panel:] I just realized these are literally the same people

In this comic, two groups of angry protesters are presented and labeled. They are probably not actually protesting side by side, but simply drawn side by side to compare their similarities. The left group represents the Fashion Police with Cueball holding a sign implying that Crocs are prohibited (by showing Crocs shoe/sandall in a circle with a strike through it). Crocs are a type of clogs made of foam. Crocs (and their imitators) have become fairly popular due to their low price, comfort, and ease of use, but are broadly considered unfashionable to wear in public . It is not the first time Randall mocks a special type of shoes, previously in 1065: Shoes Randall was after shoes that has those creepy individual toes like Vibram FiveFingers . They will also never be a hit with the Fashion Police. [ citation needed ] The right group represents the Grammar Police with another Cueball holding a sign with three homophones: Their (belongs to them), They're (contraction meaning "they are"), There (a location). These words, due to their common usage and identical pronunciation are frequently confused for one another, with one spelling being used in a context meant for a different one, causing the Grammar Police to quickly intervene (see 386: Duty Calls ). See the Grammar Police on Twitter and also Linguistic prescription which comes up on Wikipedia when searching for Grammar Police. The two groups look similar, standing in similar poses, with one Cueball holding signs in each group, and Megan in the front line of both groups. Each group also has one member brandishing a sword, indicating the exaggerated level of intensity they feel about their respective causes. Both types of people will correct, criticize, denigrate or mock those who fail to conform to their criteria for what is "correct". Fashion police oppose people wearing clothing that's mismatched, out of style/ fashion or simply "ugly" to them. Grammar police are "sticklers" for grammar rules and have an immediate negative reaction when someone uses non-standard grammar in a sentence. These two groups are generally seen as socially separate, and their goals appear very distinct, but the comic explains how the two groups are actually very similar. This is demonstrated by listing eight characteristics (plus a ninth in the title text) common to both groups. See explanation in the table below . In the caption below the comic Randall notes that he just realized that these are literally the same people because they both exhibit the listed traits. It seems like a safe assumption (see 1339: When You Assume ) that there are more grammar pedants (see title text of 1652: Conditionals ) than fashion police people who read xkcd, and it also would seem likely that many xkcd readers would dislike the Fashion Police. This comic may, therefore, be intended to point out to grammar pedants that their behavior is functionally similar to that of other people who they dislike. Ponytail also represented the grammar police in 1576: I Could Care Less , where Megan puts her in place after she polices her sentence; this thus shows what Randall thinks about such police work and supports the above assumption. In 1576: I Could Care Less, "literally" was also used in the title text. Randall is, with regards to language, definitely one of those that can belong in this group: To seem cool and casual, pretend to ignore them while understanding them very well. The title is a ninth point to add to the list, with the asterisk in front representing one more bullet. See the last entry in the table below for more: [Beneath two headings to the left and right are shown two aggressive-looking groups of people with only the four people in the front clearly shown for each group. Behind them five other people can be seen, but they are not drawn with the same solid line and are only partly shown behind the first four, but legs from all five in each group can be seen along with some heads (all Cueball like) and arms etc. The front of the left group consist of Hairy holding a fist up towards left, Megan with her arms crossed in front of her chest, Cueball holding a sign, using both hands, straight up above his head and another Cueball-like guy to the right is holding up a broken branch in one hand toward right. The person behind this last person is shown to hold up his fist towards right like Hairy does to the left. The sign shows a Crocs shoe in a circle with a strike through it going above the Crocs from top left to bottom right. The front of the right group consist of Megan holding both her arms over her head hands folded into fist while looking towards left, Cueball holding a sign, using both hands, towards the right and up above Ponytails head, she is raising one hand in a fist to the left and finally a bald guy with glasses is brandishing a short sword in one hand toward right while holding his other hand palm up. The sign has three similar words written beneath each other.] Left: Fashion Police Right: Grammar Police Sign: Their They're There [Below the two groups are eight points with bullets:] Judgemental and smug Angry about something deeply arbitrary Strong opinions backed by style guides Appreciate that the way that you are interpreted is your responsibility Understand that there's no way to "opt out" of sending messages by how you present yourself, and attempts to do so send strong messages of their own To seem cool and casual, pretend to ignore them while understanding them very well Vindictive about things that are often uncomfortably transparent proxies for race or social class Fun to cheer on until one of them disagrees with you [Caption below the panel:] I just realized these are literally the same people

Manhattan Project

Manhattan Project

https://www.xkcd.com/1736

https://www.explainxkcd.com/wiki/index.php/1736:_Manhattan_Project

[A five panel layout with each panel slightly narrower than the one before.] [Ponytail holding her arms out speaks to Cueball.] Ponytail: What we need to cure cancer is a new Manhattan Project! [Cueball stands next to Ponytail on podium with a banner overhead. Ponytail is lifting her arms high up and addresses a huge crowd below the podium. Faces disappear into the distance, but at the podiums edge are four full faces, from left to right they are Hairy, a person with flat hair, a person with white hair and a Cueball-like guy.] Banner: Research Initiative [Cueball and Megan sitting behind a desk looking out and Ponytail standing to the right facing away from them wear laboratory goggles and laboratory coats. There are several Erlenmeyer flasks on the desk and Ponytail is also holding such a flask. There are other glass wares on the desk.] [Megan, holding a hand in front of her face, Cueball and Ponytail, all wearing some kind of glasses strapped around the back of their heads stand behind two chest-height barriers looking into the distance where a large mushroom cloud rises high in the air with the typical ring around the stem below the main cloud and smoke/dust surrounding the bottom of the stem. It is much higher in the image than the three mountains in the left background.] [Close up of Ponytail, as she faces to the right. She is wearing very dark protection glasses, looking like those used for looking at the sun during a solar eclipse.] Ponytail: Wait.

The Manhattan Project was a big, expensive, secret research and development project that produced the first nuclear weapons during World War II . Because of the unprecedented scale of the project, which involved some of the brightest minds in science and the efforts of thousands of people, "Manhattan Project" has become a metaphor for any kind of all-out effort involving the top minds of a discipline to achieve a single objective, often expressed as the phrase " We need a new Manhattan Project ". The day before this comic was released the following announcement was made: Microsoft will ‘solve’ cancer within the next 10 years by treating it like a computer virus . And on the day this comic was released (but probably after the comic was released) there was a press conference where Mark Zuckerberg and Priscilla Chan Pledge $3 Billion to Fighting Disease (all disease in general.) This is the kind of projects that could be called Manhattan type projects and these (at least the Microsoft announcement) could be the reason this comic came out now. In this comic, Ponytail starts by making the suggestion that they should create a "new Manhattan Project" to cure cancer. Taken figuratively, this would imply a heavily-funded, massive collaborative effort involving the best scientists in the field of cancer research , and is not an unreasonable idea in itself. However, she and her fellow scientists all take the idea literally instead, and the New Manhattan Project ends up actually developing a nuclear bomb. In the final panel, Ponytail appears to realize that this runs somewhat counter to her original objective [ citation needed ] (not to mention is redundant, as the original Manhattan Project already invented the nuclear bomb). The title text hastily justifies this mistake by claiming a partial success; that their nuclear detonation did, indeed, kill all cancer within the blast radius of the explosion. However, it fails to mention that the blast would also kill everything else as well. It also admits that the explosion would most likely end up causing more cancer due to the ionizing radiation and fallout . The title text is reminiscent of both the main comic and the title text of 1217: Cells . This was the first time since 1355: Airplane Message , more than two years prior, that Randall mentions cancer (on a banner!), a recurring subject on xkcd, but mainly around the time when his then-fiancée (now wife) was diagnosed with Stage III breast cancer in October of 2010. Interestingly enough there are only two facts in that previous comic, and that other fact (from the title text) was referenced the week before this comic came out in 1732: Earth Temperature Timeline . But it could be a coincidence. The Manhattan Project was the scene of 809: Los Alamos , and a story from the site is being told in 1520: Degree-Off . According to 980: Money the Manhattan project used $24,400,000,000. Nuclear weapons in general has been a recurrent subject on xkcd and their invention was also mentioned last week in 1732: Earth Temperature Timeline around 1950 CE. The previous comic with a similar mushroom cloud was 1655: Doomsday Clock , and in that comics explanation at least three other "recent" comics about such weapons of mass destruction are mentioned. [A five panel layout with each panel slightly narrower than the one before.] [Ponytail holding her arms out speaks to Cueball.] Ponytail: What we need to cure cancer is a new Manhattan Project! [Cueball stands next to Ponytail on podium with a banner overhead. Ponytail is lifting her arms high up and addresses a huge crowd below the podium. Faces disappear into the distance, but at the podiums edge are four full faces, from left to right they are Hairy, a person with flat hair, a person with white hair and a Cueball-like guy.] Banner: Research Initiative [Cueball and Megan sitting behind a desk looking out and Ponytail standing to the right facing away from them wear laboratory goggles and laboratory coats. There are several Erlenmeyer flasks on the desk and Ponytail is also holding such a flask. There are other glass wares on the desk.] [Megan, holding a hand in front of her face, Cueball and Ponytail, all wearing some kind of glasses strapped around the back of their heads stand behind two chest-height barriers looking into the distance where a large mushroom cloud rises high in the air with the typical ring around the stem below the main cloud and smoke/dust surrounding the bottom of the stem. It is much higher in the image than the three mountains in the left background.] [Close up of Ponytail, as she faces to the right. She is wearing very dark protection glasses, looking like those used for looking at the sun during a solar eclipse.] Ponytail: Wait.

Datacenter Scale

Datacenter Scale

https://www.xkcd.com/1737

https://www.explainxkcd.com/wiki/index.php/1737:_Datacenter_Scale

[Zoom in on a woman with a bun holding her hand palm up in front of her taking to people off-panel right.] Woman with a bun: RAID controllers don't make sense at our scale; everything is redundant at higher levels. When a drive fails, we just throw away the whole machine. [In this frame-less panel it is revealed that the woman with a bun talked to Cueball and Ponytail who is looking her way.] Cueball: Machine? We throw away whole racks at a time. Ponytail: Yeah, who replaces one server ? [Hairy has appeared from the left and holds one hand palm up towards the other three where also the woman with a bun has turned towards him.] Hairy: We just replace whole rooms at once. At our scale, messing with racks isn't economical. Woman with a bun: Wow. Cueball: Like Google! [Megan walks in from the left, and everyone including Hairy now looks towards her. Cueball has taken a hand up to his chin. The replies to Megan are written with clearly smaller font.] Megan: We don't have sprinklers or inert gas systems. When a datacenter catches fire, we just rope it off and rebuild one town over. Hairy: Makes sense. Cueball: I wonder if the rope is really necessary.

This comic expands, to the limit, the strategy that it's a net cost saving to allow cheap hardware to fail and simply replace it than to have robust but much more expensive systems to start with. The technique was made famous by Google circa 1999, when its successful cost-effective server designs were actually using sub-consumer, nearly junk, hardware. RAID ("redundant array of independent disks") is a technology that splits data across several hard drives as if they were one. RAID comes in several levels (varieties) which have different applications, but one of the big applications of RAID is creating mirrored hard disks that back each other up. If one disk drive in such a RAID fails, no data is lost. However, RAID is complicated to configure, so you don't want to be constantly setting it up. An alternative technique for data centers is, therefore, to simply send the data to several servers at once. This makes maintenance easier, but without RAID, one hard disk crash basically breaks the server. However, this is what the woman with a bun's (possibly an adult Science Girl ) data center is doing since their scale is so large that fixing individual servers actually more expensive than simply buying a new one for replacement, and instead of fixing the drive they throw away the machine. (More about this approach will be explained later on) From here, the comic starts to exaggerate. Nowadays, servers can be made extremely small (" Blade servers ") and dozens of servers can be attached to one 19-inch rack in a data center. Rather than going to the effort of unplugging and unscrewing one blade from the rack, when a blade fails at Cueball 's data center they just throw away the rack, and Ponytail agrees and mildly mocks the woman with a bun for replacing one server. Hairy 's data center goes one step further - they have so many servers that they would constantly have to be throwing away and replacing racks, so instead they just build a new room when one rack fails. This would be currently possible with small modular data centers that are built in shipping containers for easy transport and can be linked together to expand capacity. Here the cargo-container "room" with the failure would be quickly swapped with a fresh one. Cueball adds "like Google!" - Randall previously mentioned Google's approach to hard drive failures in the what if? Google's Datacenters on Punch Cards . Back in 2007 they had one failure every few minutes, which might have increased hugely since then. Finally Megan appears and her company, of course, breaks the scale of silliness in exaggeration. She says that they don't have any fire extinguishers (neither regular sprinklers nor the systems that deploy gasses like FM-200 which alter the room air's ability to sustain a fire). Rather, they just rope the center off, thus letting the data center burn down. Then they simply move a town over and build a new one. This may indicate they are so big that the entire town will burn down if their center catches fire, for else they did not have to skip town. Alternatively, they just leave the center burning and this may cause problems in that town, so they simply flee the premises. Most big internet companies do have multiple redundant data centers around the world, in order to increase speeds for users in different countries, but Megan's idea would be very expensive, result in increased latency , possibly kill people (either in their company, or other people in the town and since they do not try to put out the fire), and cause severe destruction of properties in addition to their own. These last two items would result in additional litigation and fines, and potentially jail sentences for the people charged with implementing the policy. They may also result in other towns being unwilling to take their business, out of fear they will wind up burning too. Hairy still thinks that it makes sense, while Cueball wonders what difference the roping off does. This could again be a reference to the fact that they just let the buildings burn without bothering about the local consequences, and the next step is just one more step towards the extreme of the title text. This comic references how, as data requirements expand, the cost of time eventually outweighs the cost of hardware at ever increasing scales (drive, rack, room, building). While this comic takes this to the extreme, with whole buildings being destroyed for simple flaws, the concept is not as far-fetched as it seems if "thrown out" is taken to include being sold to equipment refurbishers. It could indeed be cost effective for a large data services provider to resell racks or even whole data center modules at some significant fraction of their "as new" price as opposed expending the time and effort to attempt a repair. The equipment refurbisher would then rely on a cost advantage like cheaper labor to repair the flaw and sell it back to Google or another company with less demanding requirements. Equipment rental firms already operate on this model and with the added incentive customers preferring to rent newer models, this means that the equipment is often preemptively replaced before failures even occur. The title text refers to Isaac Asimov 's science-fiction short story The Last Question ( comic version ), where humanity asks, at different stages of its spatial and technological development, the same question to increasingly advanced computers: "How can the net amount of entropy of the universe be massively decreased?". At each point, the computer's answer is that it does not yet have sufficient data for a meaningful answer. Ultimately, the computers are all linked through hyperspace, outside the physical boundaries of the universe, and make up a single computing entity named AC which keeps pondering the question even as the heat death of the universe occurs and time and space cease to exist. When AC finally discovers the answer, since there is nobody left to report it to, it decides to demonstrate it and says " LET THERE BE LIGHT! ", which are the first words said by God during the Creation, according to the Book of Genesis . Here, the title text implies that, as the universe died, AC no longer had a use for it as a physical support and, taking the comic's logic to the next extreme, chose to discard it and get a brand-new one instead of bothering to "fix" it by reversing its entropy. This short story was also referenced in 1448: Question . This comic's concept of taking a real world phenomenon and exaggerating it to levels currently considered implausible for comic effect closely mimics an earlier comic which describes progressively more "hardcore" programmers in 378: Real Programmers . This comic might be related to 1567: Kitchen Tips which suggests not throwing away your dishes but washing them. [Zoom in on a woman with a bun holding her hand palm up in front of her taking to people off-panel right.] Woman with a bun: RAID controllers don't make sense at our scale; everything is redundant at higher levels. When a drive fails, we just throw away the whole machine. [In this frame-less panel it is revealed that the woman with a bun talked to Cueball and Ponytail who is looking her way.] Cueball: Machine? We throw away whole racks at a time. Ponytail: Yeah, who replaces one server ? [Hairy has appeared from the left and holds one hand palm up towards the other three where also the woman with a bun has turned towards him.] Hairy: We just replace whole rooms at once. At our scale, messing with racks isn't economical. Woman with a bun: Wow. Cueball: Like Google! [Megan walks in from the left, and everyone including Hairy now looks towards her. Cueball has taken a hand up to his chin. The replies to Megan are written with clearly smaller font.] Megan: We don't have sprinklers or inert gas systems. When a datacenter catches fire, we just rope it off and rebuild one town over. Hairy: Makes sense. Cueball: I wonder if the rope is really necessary.

Moon Shapes

Moon Shapes

https://www.xkcd.com/1738

https://www.explainxkcd.com/wiki/index.php/1738:_Moon_Shapes

[Caption above the panel:] Interpreting the shape of the moon in art [The left part of the panel shows a two column chart is shown with labels above the columns. The left side shows the moons shape as white on a black square. These types of moons could be seen in certain art pieces. The right side saying whether this is normal or not as indicated with a green check mark or a red X. Right of the second column there are explanations of why the specific type of moon is marked as it is and what it could be called or how it could be possible even with the red X. The upper three moons have one common explanation as indicated with a bracket that covers all three with the text on the middle part of the bracket. Similarly moon five and six also have a bracket and only one explanation.] Shape Normal? [Shape #1-3 shows a white circle (full moon), a more than half full moon (Gibbon) and a thin seal at the bottom right of the square.] ✓ ✓ "Full" or "Quarter" or "Harvest" or "Wax Gibbon" or whatever ✓ [Shape #4 same as #3 but with the seal in the upper part of the square.] X Not possible at night [Shape #5-6 shows a full moon with a circular section taken out of the right side and a seal that goes almost all the way around the circumference of the moon with almost a full circle taken out of the top left part of the moon.] X X Only possible during a lunar eclipse (#1 only, dubious) or a solar eclipse (bright part is the Sun) [Shape #7 same as #3 but with the seal a little smaller and more to the top and less to the left. Around the moon there are several starts represented with 29 small white dots. In the center of the black square there is a black circle, coinciding with the outer rim of the seal. Within this circle (the dark side of the moon) there are no stars!] ✓ Looks OK [Shape #8 same as #7 but apart from the 29 small white dots from before there are now also 6 more dots inside the dark circle with no stars in #7.] X There's either a hole in the Moon or a nuclear war on its surface.

The Earth's Moon , being the most prominent object in the night sky (most of the time), is a frequent subject of art; particularly art depicting a nighttime scene. Unfortunately, the moon often appears in works of art in ways that are very dramatic and would not be realistically possible. It may be done out of ignorance, or knowingly by taking artistic license . As someone interested in and who has worked in astronomy, this likely bothers Randall . The Moon is well known to have " phases " describing what portion of the visible surface of the moon is illuminated by sunlight and highly visible, and what portion is dark, and generally only slightly visible when the moon appears while the sun is also up. These phases progress between "New" (when the surface facing the Earth is completely dark) and "Full" (when the surface facing the Earth is completely illuminated, appearing as a full disk as viewed from Earth). Mid-way between those extreme phases is a "Quarter" Moon, when exactly one-half of the surface facing Earth is completely dark - at this point the Moon is a quarter of the way in its cycle from the New Moon, either one quarter of the way into it ("First" Quarter) or a quarter of the way from completing it ("Last" Quarter). Because the Moon is approximately spherical, its illuminated side appears as "crescent" in shape as it progresses from New to First Quarter phase. As it progresses from First Quarter to Full phase, observers on Earth see a Waxing " Gibbous Moon (which just means that the dark portion has formed a crescent). One can imagine this like a globe on which you draw a straight line from the north pole to the south pole down the center of the side facing you (appearing to create two semi-circles); upon rotating the globe, the line would become rounded as it moved away creating a crescent on the side the line was moved towards. Because of the geometry involved, a line connecting the two points (horns) of a Crescent Moon (or of the darkened crescent inverse of a Gibbous Moon) must be a diameter of the moon (i.e. it must pass through the center of the circle). The deliberate misidentification of a Waxing Gibbous Moon ("waxing" means going from new to full; that is increasing in illuminated area) as a "wax gibbon" (a Southeast Asian ape made of a nonpolar solid) is a source of humor in this comic. This is probably a reference to H.P. Lovecraft, who had several of his stories take place under "a gibbous moon" for dramatic effect, or even more likely a reference to the Discworld by Terry Pratchett , often referenced in xkcd (as in 1498: Terry Pratchett ). In the witch series the Gibbous Moon is mentioned several times as the most magic, rather than the more often used Crescent or Full Moon. Further, because the light portion of the Moon is illuminated by sunlight (whether or not the Moon is in the sky at the same time as the Sun), the light side of the Moon will always be facing towards the Sun. If the Moon is in the night sky, the Sun must be somewhere "below" the horizon on the other side of the Earth. Thus, at night, the light portion of the Moon must always be on the half of the Moon that faces the horizon (there are points during the daytime when the orientation can go the other way); however, because of the moon tilt illusion it is possible for the light portion of the moon to appear to point up. The moon tilt illusion is generally not as severe and may only last a few hours after sunset. It is worth noting that while the Moon's dark portion blends imperceptibly with the dark night sky, it is still a solid body. Therefore it would be impossible to see more distant objects such as stars "through" the dark portion of the Moon's circumference. This is most dramatically exemplified by a solar eclipse during which the Moon passes in front of the Sun and is therefore completely dark (the Sun is lighting only the far side), but the Moon's circumference still blocks a circular portion of the Sun's light. Therefore, if we were to see any lights in the part of the sky the dark side of the Moon blocks, they would need to be from sources between us and the Moon's surface, such as a nuclear war on the moon. This comic lists some of the some common mistakes. In some cases, a depiction may be unrealistic in multiple ways - for example, the Flag of Tunisia has both unrealistic horns and a star visible between the horns, while the Charles VI tarot shows a Moon with over-long horns pointing towards the horizon. In the title text, Randall is referring to the movie Independence Day and how one of the alien's ships (in the movie) 'eclipses' part of the Moon. He says that if the points go halfway or longer around the Moon, then he imagines it's caused by an alien ship and interprets the entire piece of art in that context (i.e. aliens are about to attack those shepherds!). [Caption above the panel:] Interpreting the shape of the moon in art [The left part of the panel shows a two column chart is shown with labels above the columns. The left side shows the moons shape as white on a black square. These types of moons could be seen in certain art pieces. The right side saying whether this is normal or not as indicated with a green check mark or a red X. Right of the second column there are explanations of why the specific type of moon is marked as it is and what it could be called or how it could be possible even with the red X. The upper three moons have one common explanation as indicated with a bracket that covers all three with the text on the middle part of the bracket. Similarly moon five and six also have a bracket and only one explanation.] Shape Normal? [Shape #1-3 shows a white circle (full moon), a more than half full moon (Gibbon) and a thin seal at the bottom right of the square.] ✓ ✓ "Full" or "Quarter" or "Harvest" or "Wax Gibbon" or whatever ✓ [Shape #4 same as #3 but with the seal in the upper part of the square.] X Not possible at night [Shape #5-6 shows a full moon with a circular section taken out of the right side and a seal that goes almost all the way around the circumference of the moon with almost a full circle taken out of the top left part of the moon.] X X Only possible during a lunar eclipse (#1 only, dubious) or a solar eclipse (bright part is the Sun) [Shape #7 same as #3 but with the seal a little smaller and more to the top and less to the left. Around the moon there are several starts represented with 29 small white dots. In the center of the black square there is a black circle, coinciding with the outer rim of the seal. Within this circle (the dark side of the moon) there are no stars!] ✓ Looks OK [Shape #8 same as #7 but apart from the 29 small white dots from before there are now also 6 more dots inside the dark circle with no stars in #7.] X There's either a hole in the Moon or a nuclear war on its surface.

Fixing Problems

Fixing Problems

https://www.xkcd.com/1739

https://www.explainxkcd.com/wiki/index.php/1739:_Fixing_Problems

[Cueball sitting in an office chair at his desk typing on his laptop. A person addresses him from the left:] Off-panel voice: What are you working on? Cueball: Trying to fix the problems I created when I tried to fix the problems I created when I tried to fix the problems I created when...

Due to the complex relationships within a program or other system, making an alteration can cause problems with other parts of the program. This can lead to a seemingly small "fix" becoming a long chain of debugging and consecutive fixes, which Cueball is in the middle of, a typical example of recursion often used in xkcd. As Cueball attempts to solve the initial computer issue, he creates more problems along the way. The title text suggests that the original problem was not stopping the function of the program and the benefits that Cueball may have hoped to achieve with the mentality of "If it ain't broke, break it and fix it" are being consumed by the expanding effort of the fix. Attempting to solve all of these problems results in more time wasted than he hoped would be gained by optimizing the inefficient tool described in the title text. Though depending on the tool, he could publish the changes once completed, allowing the community using that tool to gain back the man-hours collectively. Wondering if something is worth doing has been a subject in 1205: Is It Worth the Time? This comic is similar in thesis to 1445: Efficiency and 1319: Automation . Other relevant comics include 1171: Perl Problems , where using regular expressions causes more problems than it solves, 349: Success , where Randall comments on the goals of a project decreasing in optimism as a project goes on due to more and more problems distracting from the original, and 1579: Tech Loops , which shows that attempting to fix one problem in a piece of software can force a developer to delve into seemingly irrelevant parts of the relevant tech loop that the software in question is trapped in. [Cueball sitting in an office chair at his desk typing on his laptop. A person addresses him from the left:] Off-panel voice: What are you working on? Cueball: Trying to fix the problems I created when I tried to fix the problems I created when I tried to fix the problems I created when...

Rosetta

Rosetta

https://www.xkcd.com/1740

https://www.explainxkcd.com/wiki/index.php/1740:_Rosetta

[A control room with Megan and Hairy sitting on stools in front of an opposite desk with computers. Hairy has his arms in the air. Ponytail is standing between them with Cueball, she is watching Megan and he is looking at Hairy.] Megan: Signal lost. Megan: Rosetta has impacted the comet. Ponytail: Good work everyone. Hairy: Woooo! [Zoom on Ponytail, still looking at Megan and Cueball who has turned towards Ponytail.] Cueball: So. Cueball: Do you think we deflected it? [Ponytail turns to Cueball as does Hairy who turns and looks away from his computer.] Ponytail: Huh? Cueball: Did we hit the comet hard enough to deflect it away from Earth? [In a frame-less panel Ponytail talks with Cueball.] Ponytail: That... Is that what you thought we were doing? Cueball: I just assumed... [Megan enters whispering in Ponytail's ear, holding a hand up to her mouth. Ponytail still looks at Cueball who raises his arms up in the air.] Megan: He's a huge Armageddon fan. Let him have this. Ponytail: Okay, fine. Ponytail: Yes! We did it! The Earth is saved! Cueball: Wooo!

On the day this comic was posted (September 30th 2016), the Rosetta mission ended with the final descent of Rosetta onto the comet 67P . Landing Rosetta on the comet gave the scientists ( Ponytail , Megan and Hairy ) a chance to collect extra data from very close to the comet, using the spacecraft's powerful sensors. Cueball however assumed that the landing was a " kinetic impact " mission to deflect a comet that was on a collision course with Earth. A similar scenario (but using a nuclear weapon implanted inside of the asteroid to deflect it) was depicted in the 1998 film Armageddon , of which Cueball is apparently a fan. Armageddon is a high-throttle action movie, infamous among NASA employees for its incredibly liberal application of artistic license. IMDb has a list of factual inaccuracies . In reality, at the time Rosetta landed, 67P was already leaving the inner solar system and was a long way past Earth . It will return to the inner solar system in around 5 years' time, but its orbit will not pass close to the Earth in any foreseeable time. Also, as the title text hints, Rosetta's speed was only 90 cm per second relative to the surface at the moment of impact (or about 2 mph/3.25 km/h; the speed of a slow walk), while the comet was traveling at 14.39 km/s. Given that Rosetta only weighs a couple of tons (or six horses ), and 67P weighs nearly 10 billion tons (or 22 billion horses), Rosetta's landing will have no actual measurable effect on the comet's momentum. Rosetta (and its lander, Philae ) were previously the subject of the comics 1402: Harpoons and 1446: Landing , and were mentioned in 1461: Payloads , 1547: Solar System Questions and possibly 1621: Fixion . [A control room with Megan and Hairy sitting on stools in front of an opposite desk with computers. Hairy has his arms in the air. Ponytail is standing between them with Cueball, she is watching Megan and he is looking at Hairy.] Megan: Signal lost. Megan: Rosetta has impacted the comet. Ponytail: Good work everyone. Hairy: Woooo! [Zoom on Ponytail, still looking at Megan and Cueball who has turned towards Ponytail.] Cueball: So. Cueball: Do you think we deflected it? [Ponytail turns to Cueball as does Hairy who turns and looks away from his computer.] Ponytail: Huh? Cueball: Did we hit the comet hard enough to deflect it away from Earth? [In a frame-less panel Ponytail talks with Cueball.] Ponytail: That... Is that what you thought we were doing? Cueball: I just assumed... [Megan enters whispering in Ponytail's ear, holding a hand up to her mouth. Ponytail still looks at Cueball who raises his arms up in the air.] Megan: He's a huge Armageddon fan. Let him have this. Ponytail: Okay, fine. Ponytail: Yes! We did it! The Earth is saved! Cueball: Wooo!

Work

Work

https://www.xkcd.com/1741

https://www.explainxkcd.com/wiki/index.php/1741:_Work

[A table is shown with a glass of water to the left and a lamp standard type desk lamp on the right. There are nine labels in relation to different parts of these three items. For each label, one or two arrows points to the relevant part. Five labels are written above the table, two on the table and two below the table between the front legs. These last two labels are causing the table legs to the rear to disappear, and also cuts the lamp cord, going beneath the table, in two. Below each label will be written under a description of what they point to going in normal reading order from left to right, two lines above, one line on and one line below the table.] [Arrow points a line that follow the curve of the lamps shade:] An engineer worked late drawing this curve in AutoCAD [Arrow points to back of lamp shade just above the stem. The shade has four visible vents on the front. The part the arrow points to is not visible:] Extra vents added to avoid California safety recall [Arrow points to glass:] Years-long negotiation with glass supplier [A double arrow is placed above the center of the glass, ending on two lines above the edges of the glass:] 4 hours of meetings [Two arrow points on either side of the lamp's stem:] 9 hours of meetings [Two arrow, one pointing up at the bottom and the other down at the inside bottom of the glass:] Months of tip-over testing [An arrow points to the lamp information sticker on the bottom part of the lamps base. Unreadable text can be seen as thins lines on the sticker:] Ongoing debate [An arrow points to the front edge of the desk, ending in a starburst on the edge:] Wood source changed due to 20 year legal fight over logging in the Great Bear rainforest [Arrow points to the switch on the lamps cord which can be seen going over the right edge of the table and hanging down below the table. The switch can be seen just under the table edge:] Argument over putting switch on cord got someone fired [Caption under the panel:] Sometimes I get overwhelmed thinking about the amount of work that went into the ordinary objects around me.

This comic details a set of theoretical examples of how much work went into the design and manufacture of everyday objects. See explanation of individual design elements below. The joke centers around the fact that most people in modern times are constantly surrounded with human-built objects, which we generally use without giving them much thought. Randall implies that he occasionally imagines what went into seemingly simple objects around him (in this case his desk and the water glass and the desk lamp on top of it), and finds it overwhelming. This is because there are so many built items around us, many of which are inexpensive and mass-produced, which nonetheless resulted from a great deal of human effort. This is similar to the thesis of the classic essay I, Pencil , except that while I, Pencil idealizes manufacture and commerce to argue for the free market and against regulation, the comic focuses on details that are far more human or based in bureaucratic or government red tape. Presumably, this kind of realization is more likely for people who've worked in design and engineering, like Randall, because they have some insight into what's involved in bringing a product to market. Also people who sit around all day wondering what could be funny, like Randall, could also end up in such a thought spiral. The comment about California recalls is based on the tags on products that often state "This item has been known by the state of California to cause..." There's a double joke in the title as the first thing most people will think of, when seeing such a table with a typical desk lamp, is that this is a work desk rather than about all the work put into making the desk and lamp. The potential implication is that Randall is so distracted imagining the work that went into creating his workspace that he can't get his own work done, hence the title. (Interestingly, but without being related to this comic, the next comic was called 1742: Will It Work ). The argument over putting the switch on the cord getting someone fired hits on another aspect of the design issue. Companies that design and manufacture goods will inevitably have human conflicts, where decisions will be argued over, and human personalities and office politics will impact the final design. In the title text Randall states that this incidence is imaginary (based on his imagination) but still he has apparently come up with an entire fictional narrative about the conflict over whether to put the lamp's switch on the lamp body itself, or to attach it to the lamp's power cord. And now he has SUCH a strong opinion about the firing incident. This may be because he already had a strong opinion about who was right, which could make him angry if that person was the one getting fired. Randall's distaste for lamps where the switch is on the cord was mentioned in the title text of 1036: Reviews . As the lamp on this desk is with the switch on the cord, and as it seems Randall really dislikes such lamps, this would make sense, as it would probably be the one wishing to put the switch on the body who were fired. Alternatively it could have been the one who put the switch on the wire that was fired later, when they got poor on-line reviews... Using the lamp as shown on this desk would make it annoying with the switch on the cord, as it will be hard to reach under the table, when sitting at the desk. Often such lamps have the switch either at the main body or on the head of the lamp. That would make it easy to reach it while sitting at the desk. A similar theme of the unseen contributions of engineers is found in 277: Long Light , including the title text: "You can look at practically any part of anything manmade around you and think 'some engineer was frustrated while designing this.' It's a little human connection." This fits in well with Randall's annoyance with a switch on the cord, as he might believe it was a frustrated engineer that is the cause of such an inconvenient placement of the switch. [A table is shown with a glass of water to the left and a lamp standard type desk lamp on the right. There are nine labels in relation to different parts of these three items. For each label, one or two arrows points to the relevant part. Five labels are written above the table, two on the table and two below the table between the front legs. These last two labels are causing the table legs to the rear to disappear, and also cuts the lamp cord, going beneath the table, in two. Below each label will be written under a description of what they point to going in normal reading order from left to right, two lines above, one line on and one line below the table.] [Arrow points a line that follow the curve of the lamps shade:] An engineer worked late drawing this curve in AutoCAD [Arrow points to back of lamp shade just above the stem. The shade has four visible vents on the front. The part the arrow points to is not visible:] Extra vents added to avoid California safety recall [Arrow points to glass:] Years-long negotiation with glass supplier [A double arrow is placed above the center of the glass, ending on two lines above the edges of the glass:] 4 hours of meetings [Two arrow points on either side of the lamp's stem:] 9 hours of meetings [Two arrow, one pointing up at the bottom and the other down at the inside bottom of the glass:] Months of tip-over testing [An arrow points to the lamp information sticker on the bottom part of the lamps base. Unreadable text can be seen as thins lines on the sticker:] Ongoing debate [An arrow points to the front edge of the desk, ending in a starburst on the edge:] Wood source changed due to 20 year legal fight over logging in the Great Bear rainforest [Arrow points to the switch on the lamps cord which can be seen going over the right edge of the table and hanging down below the table. The switch can be seen just under the table edge:] Argument over putting switch on cord got someone fired [Caption under the panel:] Sometimes I get overwhelmed thinking about the amount of work that went into the ordinary objects around me.

Will It Work

Will It Work

https://www.xkcd.com/1742

https://www.explainxkcd.com/wiki/index.php/1742:_Will_It_Work

[Caption above the panel:] Likelihood you will get code working based on how you're supposed to install it: [A chart with a double arrow going from the top to the bottom. Both arrows are labeled. Along the arrow, six labels follow from top to bottom. The first five take up different amounts of space, but the space between them (bottom of one to top of the next) is the same and resembles a typical line shift between paragraphs. The space, however, to the last label is more than three times as wide.] Very likely App store or package manager GitHub Link SourceForge Link Geocities/Tripod Link Copy-and-paste example from paper's appendix Anything that "requires only minimal configuration and tweaking" Unlikely

This comic humorously lists how likely computer code is to function on the user's computer based on the source of the code. App store or package manager: Most likely referring to the Apple's Mac or iOS App Store , Google's Google Play , Microsoft's Windows or Windows Phone Store , or package managers such as Debian's Advanced Packaging Tool (APT). Programs in the App Store are already compiled from raw code into executable files that have been tested on their respective platform -- otherwise they would be rejected from the storefront -- and so should be expected to run with no effort from the user. Similarly, a package manager for a Linux OS handles downloading and installing the program requested, as well as installing any dependencies (other programs or libraries needed by the desired program, potentially including locusts ) automatically. GitHub Link: GitHub is a website where people can host Git repositories of code that they are working on. Since Git is built to track changes in code for an entire project, it is likely that all of the code needed to run the project is included in the download. One reason it may be less reliable than the previous entry is that it may not include external libraries expected to already be on the user's computer. SourceForge Link: SourceForge is similar in scope to GitHub : hosting source code repositories but also binary packages. But it is older and dwindling in popularity. As a result, a project hosted on SourceForge is more likely to be abandoned. Geocities/Tripod Link: Geocities is a now-defunct free website host. Tripod is a similar website host owned by Lycos . The fact that the software comes from there means that nobody has paid attention to the project since Geocities shut down, which could mean that code rot has begun to take effect, with various dependencies being less and less likely to work over time. Copy-and-paste example from paper's appendix: Some academic papers publish code or pseudocode ( example of a paper with pseudocode in appendix ) in order to illustrate their concepts, strategies or algorithms. Often this code is not meant to be compiled because it is thought to illustrate ideas rather than be used in an actual working piece of software. Copying and pasting this code and trying to compile it will rarely give satisfactory results, and that is why it is at this point in the comic's spectrum. Anything that "requires only minimal configuration and tweaking": The punchline of the comic is that something advertised as having been tested and working with "minimal configuration and tweaking" on the system it was developed on turns out to be a frustrating mess that will almost inevitably require huge fixes for anybody else trying to get it to function. It's also often used by technically advanced people who are not aware of how difficult even minimal configuration and tweaking can be for beginners. The title text refers to websites such as Stack Overflow that allow users to post questions about their code and have other users provide answers. Websites like Stack Overflow usually generate useful answers but the quality may be lower if the conversation is disgruntled (i.e. if the asker has put in very little effort to solve the problem themselves) or if the language is less commonly used. The title text of 1185: Ineffective Sorts also references executing arbitrary code until it works, in that comic the code is actually mentioned as being from StackOverflow. Saying that something "depends on the phase of the moon" usually means that there is some apparently random component to the problem, as neither the performance of a program nor the quality of answers on websites should depend on the position of the moon in its orbit. However, there was at least one case where the phase of the moon did, in fact, trigger a bug in code. This comic was released the day after Rosh Hashanah, a Jewish holiday that always occurs at or near a new moon. It is not clear whether this is why Randall was thinking about moon phases or just a coincidence. The shape of the moon was the subject of 1738: Moon Shapes released during the week before this comic was released. This comic is called Will It Work , the previous comic was just called 1741: Work [Caption above the panel:] Likelihood you will get code working based on how you're supposed to install it: [A chart with a double arrow going from the top to the bottom. Both arrows are labeled. Along the arrow, six labels follow from top to bottom. The first five take up different amounts of space, but the space between them (bottom of one to top of the next) is the same and resembles a typical line shift between paragraphs. The space, however, to the last label is more than three times as wide.] Very likely App store or package manager GitHub Link SourceForge Link Geocities/Tripod Link Copy-and-paste example from paper's appendix Anything that "requires only minimal configuration and tweaking" Unlikely

Coffee

Coffee

https://www.xkcd.com/1743

https://www.explainxkcd.com/wiki/index.php/1743:_Coffee

[Cueball and Megan are talking.] Cueball: We should make coffee for our guests. Megan: Crap. I know nothing about coffee. Cueball: We're basically fake adults. Megan: Don't panic. We can figure this out. [Megan shakes a can of coffee grounds out on the floor as Cueball watches.] Megan: We just pour the coffee grounds... [Pan to only Megan who pours a pail of water over the grounds now lying in a pile on the floor.] Megan: ...Add water... [Cueball watches as Megan vacuums up the mixture on the floor with a bag-less vacuum cleaner, the wire going off panel right behind her.] Vacuum cleaner: Vrrrr [Megan is holding the dirt canister from the vacuum cleaner over two lit gas burners on a stove. The canister free vacuum cleaner is standing behind her and Cueball is behind this watching her.] Megan: Now we just hold it over the burners... Burners: Hissss [Megan is holding the dirt canister over one shoulder while pouring the hot content into a small mug, as Cueball watches. Three wiggly lines above the liquid indicates that it is hot.] Megan: Annnd... serve. Cueball: Nice! Megan: I'm a regular Starbuck!

In this comic Cueball and Megan are anticipating guests. Offering coffee to house guests is a commonly-accepted courtesy in the United States (and most of the western world (and rest of the world)). However, they seem to be unaware of the basics of coffee making . Cueball is concerned that this lack of knowledge is an indication of their mutual immaturity (thinking of himself as a "fake adult"), This comic thus follows a frequently used theme of people growing up but finding themselves unable or unwilling to accept traditional adult roles (see 150: Grownups , 441: Babies , 616: Lease , 905: Homeownership and 1674: Adult ). While there are cultures where coffee is served to children, it is generally seen in the United States (and western world (and rest of the world)) as an adult beverage—like beer which has also served as the subject in the comic 1534: Beer . Megan is, however, confident that the necessary steps can be determined. The steps she follows however are quite unorthodox... She attempts to make coffee by pouring the ingredients on the ground (misinterpreting the meaning of "ground coffee"), sucking it up with a Dyson vacuum cleaner (misinterpreting the meaning of " vacuum brewing "), then boiling the mixture by placing the vacuum cleaner's removable plastic canister over a hot stove, and pouring the resulting sludge through the vacuum-cleaner filter (instead of a standard coffee filter ). Megan says she is a regular "Starbuck" after pouring the batch of coffee, believing the name of the cafe chain Starbucks to be synonymous with the actual job title " barista ", further indicating a general lack of knowledge regarding the subject of coffee. The Starbucks coffee chain was loosely named after the fictional character Starbuck from the book Moby Dick , so she could be referring to this, although Starbuck had nothing to do with coffee brewing! The third possible interpretation is that Megan is unaware of the reason for Starbucks' naming and thought that it was the possessive "Starbuck's" and that the founder was named Starbuck. See more trivia about Starbuck below. This method of making coffee would be very expensive as it would most likely destroy the vacuum-cleaner canister and filter. If the vacuum cleaner had ever been used, then it would not be very hygienic either, although if it had not been used then the floor would probably also be very unhygienic anyway. Since the plastic from the canister has probably also gone into contact with the sludge after being heated over open fire, there is a high risk that this "coffee" is actually poisonous for more than one reason. The title text refers to the expense of replacing the "filter", as vacuum-cleaner filters are considerably more costly than single-use coffee filters. This was the first of two comics in a row about food, the next being 1744: Metabolism . [Cueball and Megan are talking.] Cueball: We should make coffee for our guests. Megan: Crap. I know nothing about coffee. Cueball: We're basically fake adults. Megan: Don't panic. We can figure this out. [Megan shakes a can of coffee grounds out on the floor as Cueball watches.] Megan: We just pour the coffee grounds... [Pan to only Megan who pours a pail of water over the grounds now lying in a pile on the floor.] Megan: ...Add water... [Cueball watches as Megan vacuums up the mixture on the floor with a bag-less vacuum cleaner, the wire going off panel right behind her.] Vacuum cleaner: Vrrrr [Megan is holding the dirt canister from the vacuum cleaner over two lit gas burners on a stove. The canister free vacuum cleaner is standing behind her and Cueball is behind this watching her.] Megan: Now we just hold it over the burners... Burners: Hissss [Megan is holding the dirt canister over one shoulder while pouring the hot content into a small mug, as Cueball watches. Three wiggly lines above the liquid indicates that it is hot.] Megan: Annnd... serve. Cueball: Nice! Megan: I'm a regular Starbuck!

Metabolism

Metabolism

https://www.xkcd.com/1744

https://www.explainxkcd.com/wiki/index.php/1744:_Metabolism

[Cueball, on the left, and White Hat are sitting on chairs on either side of a table, facing each other. They each have plates of food and glasses of some beverage set in front of them. Each has picked up a portion of food on a fork to eat it.] Cueball: I have one of those metabolisms where I can eat whatever I want and my body converts it to energy and stores the excess as fat.

Eating is fundamentally a process where energy from food gets absorbed into the body in order to drive every cellular process in the body. Energy that is absorbed but not needed in the short term gets converted and stored as body fat. This is called metabolism . Consuming too much food and not exercising enough are major factors for obesity , which is a problem in many first world countries today, especially in the United States . For obese people, losing weight is often an enormously difficult task. Standing in stark contrast, there are also lean people who do not seem to ever gain any weight even though they appear to eat whatever and however much they want. This leads some people (including the lean people themselves) to believe that one can have a special metabolism where excess food energy somehow does not affect the body. This belief is common, though not supported by scientific evidence. The comic makes fun of that kind of notion. While Cueball describes to White Hat how his metabolism is "special" (the phrase "one of those" implicitly meaning unusual), he is in fact only describing the normal case: no matter what he eats, his body converts the food to energy and stores any excess food as fat which stays in his body for future use. The title text stretches this further, telling about the normal habit of drinking water (and the consequences of not drinking it) as something odd. Starting to feel bad at first and eventually dying if refraining from drinking for too long a time are perfectly normal consequences of dehydration. This was also touched upon in 1708: Dehydration , in which Megan spent all day researching whether low-grade dehydration is really a thing -- ironically forgetting to eat or drink at all, to predictable results. Obesity has only fairly recently become a public health issue due to lifestyle changes brought on by technologies such as industrialization and trade. Human bodies evolved under conditions where it was hard to ever find enough to eat, so to store as much excess energy as possible as fat was a beneficial adaptation. Historically, stored fat would be consumed during hard times that was sure to come. The act of collecting food through farming or hunting/gathering also demanded physical labor which limited the amount of excess energy that would remain. In comparison, people nowadays hardly need to expend any energy to buy their food from a nearby market. They also have much more sedentary lifestyles and rarely ever go hungry. Without an active commitment to exercise more or eat less, there would almost never be a shortage of energy and no chance for body fat to be used. Randall has previously shown how bad his health becomes when he starts eating lots of fat (or sweet) food in 418: Stove Ownership . There are many rational explanations for why some people might not gain weight despite eating a lot. For example, it's possible that they only eat a lot during special occasions and social gatherings, where they are easily seen eating. On more private occasions when no one is watching, they could just as well eat much less or even skip entire meals. They might also lead a much more active lifestyle and thus require more energy than an average person despite their thin appearance. Other less pleasant reasons might include chronic diseases, parasite infections, or eating disorders. This is the second comic in a row about food, the previous being 1743: Coffee . [Cueball, on the left, and White Hat are sitting on chairs on either side of a table, facing each other. They each have plates of food and glasses of some beverage set in front of them. Each has picked up a portion of food on a fork to eat it.] Cueball: I have one of those metabolisms where I can eat whatever I want and my body converts it to energy and stores the excess as fat.

Record Scratch

Record Scratch

https://www.xkcd.com/1745

https://www.explainxkcd.com/wiki/index.php/1745:_Record_Scratch

[In a black area, with jagged edges, at the top of the comic is a sound effect written with white text. Below there are two frames with text. This text is narrated by Cueball standing below with four people around him. Cueball is highlighted by being drawn in the regular way whereas the other four people are drawn in light gray. Cueball has just dropped a wineglass, spilling wine on the floor to the left and dropping the glass, spilling more wine, to the right, He has his arms slightly out, and seems to be turned towards three people to the right, while looking to the left at Ponytail. Ponytail is holding a glass of wine in one hand and is the other hand up waving her fist at Cueball. On his other side Hairy is advancing towards him with both hands up in fists ready for a fight. (It could be his wine glass dropped on the floor at Cueball's feet as it is also drawn in gray). Behind Hairy is Megan also with a wine glass held in one hand, and behind her is another Cueball-like guy with a wine glass holding one arm out pointing a finger at Cueball.] Record Scratch Cueball (narrating): You're probably wondering what that sound was. Cueball (narrating): Well, long ago, music was recorded on vinyl discs...

A vinyl disc (also known as a gramophone record ) is a type of storage medium that stores audio recordings on the disc by carving the audio data into a continuous spiral groove on the surface of the disc. These are typically played on a phonograph (also known as record players (since 1940s) or, most recently, turntables). The player spins the disc as a stationary stylus rides along the groove. The movement of the stylus along the groove is converted by an electromagnetic or piezoelectric transducer into a corresponding electric current, which an amplifier then converts to sound. The noise referred to as a "record scratch" can be caused by someone attempting to stop a record's play by dragging the stylus across the radius of the record, or by stopping the disc's rotation with one's hand (opposing the turntable's rotation). As a result, this is often used as a sound effect in movies for comedic effect. This type of sound is also often used in hip-hop music; in particular, rapidly and manually rotating the disc in both clockwise and counterclockwise directions. The comic pokes fun at a movie cliché in which the story opens with the main character in some kind of unbelievable predicament, followed by a record scratch, seemingly freezing time (using the sound of a sudden pausing of a record to symbolize the sudden pausing of time in the movie). As the action in the film is paused, a character narrates something along the lines of, "Yup, that's me. You're probably wondering (how I ended up in this situation)..." The rest of the story then follows, often with the film going back in time to depict the events that leads up to the situation of the opening scene. In this case, it would be interesting to know why Cueball is at a party where everyone has wine glasses in their hands, but suddenly one of the glasses (Cueball's or his nearest adversary's) is lying on the floor, and it seems like a fight is about to break out. This is what an opening narration might begin to explain (typically in a flashback) after the record scratch. At the time of the comic's posting, parodying the cliché, variations on the phrase had become a popular meme on social media. As the record scratch continues to be used despite the fact that record players (gramophones) have largely become obsolete technology, Randall pokes fun at this by beginning this meme by giving the backstory on what that sound actually is, (as many people from the younger generation may very well not know this), rather than giving context to the situation via a story. This is yet one more of Randall's comics that is trying to make people feel old , and is likely most relevant to those who have actually used vinyl to listen to music, comedy or other recordings. The title text indicates (in a manner similar to that of 891: Movie Ages ) that the "78-rpm era" – referring to the fact that the original industry standard of records making 78 revolutions per minute (rpm) (1925-1950s) – is now closer to the time of the American Civil War (1861-1865) than it is to present day, another way that Randall is making the reader feel old. Note; these 78 rpm records were made of shellac, not of vinyl. [In a black area, with jagged edges, at the top of the comic is a sound effect written with white text. Below there are two frames with text. This text is narrated by Cueball standing below with four people around him. Cueball is highlighted by being drawn in the regular way whereas the other four people are drawn in light gray. Cueball has just dropped a wineglass, spilling wine on the floor to the left and dropping the glass, spilling more wine, to the right, He has his arms slightly out, and seems to be turned towards three people to the right, while looking to the left at Ponytail. Ponytail is holding a glass of wine in one hand and is the other hand up waving her fist at Cueball. On his other side Hairy is advancing towards him with both hands up in fists ready for a fight. (It could be his wine glass dropped on the floor at Cueball's feet as it is also drawn in gray). Behind Hairy is Megan also with a wine glass held in one hand, and behind her is another Cueball-like guy with a wine glass holding one arm out pointing a finger at Cueball.] Record Scratch Cueball (narrating): You're probably wondering what that sound was. Cueball (narrating): Well, long ago, music was recorded on vinyl discs...

Making Friends

Making Friends

https://www.xkcd.com/1746

https://www.explainxkcd.com/wiki/index.php/1746:_Making_Friends

[Cueball is walking with Ponytail holding her arms out while talking.] Ponytail: Making friends is so much harder once you're out of school. Ponytail: Everyone's so busy. And how do you even meet people? [In this frame-less panel Cueball raises his arms in front of his chest while they walk on.] Cueball: Here's what I do: Cueball: I pretend to be weak and injured, and wait for others to start circling, hoping to take my food, shelter, and nutrients. [Cueball stop walking and lifts both arms straight out as Ponytail turns towards him.] Cueball: Then, before they can descend, I start telling them cool facts about space until they like me. Cueball: Bam , friendship! Ponytail: This explains a lot.

Ponytail is complaining to Cueball that it is hard to make new friends once you are out of school. She even has problems just meeting new people, let alone making those new people her friends. This is a common problem, or maybe rather an advantage of going to school. In school you are forced together with a group of people you have to see everyday and work together with in groups. This is a great catalyst for making new friends. In the early grades the kids haven't had time to form many friendships so they are ready to make new friends, and later in college the young people often move away from their home town, and thus have no friends in their new town, and are again ready to make friends. Later in life it is rare to be put in a similar situation, and the people you do meet might already have several friends; for most people there is usually a rather low limit on how many friends it is possible to keep close. Thus many feel it is hard to make new friends compared to when they went to school. Cueball has a solution, but it is very weird. He says he pretends to be injured, and then, as if he were a weak animal on the savanna , he expects other people to begin circling around him, not directly to eat him, but to take his food, shelter and nutrients . This is a weird formulation as nutrients is what you get from your food, so either he is referring twice to his food, or he actually refers to his value as nutrient (i.e. food) for another being. Also it is unlikely for a person to steal his shelter, unless this refers to his clothing, as "the shelter" would usually be seen as a normal person's house, which is rather hard to take [ citation needed ] , especially if the person is renting and it belongs to someone else. He then talks about these possible future friends as if they will descend on him, making it sound even more like they are birds hanging above him like vultures . But his plan is to start telling these people who are ready to rob him of his life support cool facts about space before they get a chance to descend, and then make them like him based on this knowledge. And then before they know what hit them, they are instantly his friends. If this were actually about vultures, his method could be used to trap said vultures, a trick that might be used to try and capture vultures by tricking them to come down in order to eat them yourself (if stuck in a desert, etc). Cueball seems to think this is a fantastic idea, as shown by his arm gestures. But Ponytail seems to think otherwise. Her comment this explains a lot is probably a reference to other strange habits of Cueball that she has observed. Or his lack of other friends. Or there was a story about how they met that had confused her until this conversation occurred... The logic of Cueball's "friends" could be that Cueball is extremely rich. If he pretends to be near death, some cynics might try to become closer to Cueball to gain at least some of Cueball's wealth upon his death. In the title text Ponytail mentions that what Cueball has just described fits well with the behavior of turkey vultures rather than humans. Turkey vultures are a type of bird of prey which feeds on carrion. They are known to identify and circle weak, injured, dead or dying animals so they can eat them (take their nutrients). As they are animals they would not care about cool facts about space, but Cueball did seem to talk about other humans in the main comic. The title text, however, goes even further out this line and have Cueball cite his mom: "My mom always told me a turkey vulture is just a friend you haven't met yet, usually because you don't smell enough like decaying meat." This is a reference to the old saying: "A stranger is just a friend you haven't met yet", and the action of the vultures eating dead animals. Smelling of decaying meat would be likely to attract the vultures but it should be noted that this is likely to drive away most other potential (human) friends, as most people don't like the smell of decaying meat. [ citation needed ] Also, there is very little reason to believe that you could become friends with vultures , although if you get up and show that you are not really injured, they are likely to give up and fly away rather than attack you, unless they are starving . Vultures hanging in the air over prey that is about to die, was also the subject of 926: Time Vulture . Saying cool things about space, hoping that people like you, was the subject of 1644: Stargazing . The comic 1485: Friendship , was not about friendship... [Cueball is walking with Ponytail holding her arms out while talking.] Ponytail: Making friends is so much harder once you're out of school. Ponytail: Everyone's so busy. And how do you even meet people? [In this frame-less panel Cueball raises his arms in front of his chest while they walk on.] Cueball: Here's what I do: Cueball: I pretend to be weak and injured, and wait for others to start circling, hoping to take my food, shelter, and nutrients. [Cueball stop walking and lifts both arms straight out as Ponytail turns towards him.] Cueball: Then, before they can descend, I start telling them cool facts about space until they like me. Cueball: Bam , friendship! Ponytail: This explains a lot.

Spider Paleontology

Spider Paleontology

https://www.xkcd.com/1747

https://www.explainxkcd.com/wiki/index.php/1747:_Spider_Paleontology

[The Sphere, a time-traveler depicted as a solid floating black energy sphere surrounded by six outwardly-curved segments) seems to have materialized in front of Megan and Cueball who is in the right part of the panel facing left towards it. The Sphere looks like this except in the zoom in from panel two. A voice emanates from the Sphere.] Sphere: I'm here from the distant future! Megan: Cool! What for? Sphere: Spiders! [A close-up of the Sphere, still depicted as a black sphere, but not perfectly round at this zoom level and also clearly with some white dots in the dark area. It is also now surrounded by seven (rather than six) narrow rays with irregular dots between the rays. Megan answers it from off-panel.] Sphere: We've learned about your planet's spiders from fossils. Sphere: There's a whole spider craze. We have spider theme parks, spider movies, spider costumes... Sphere: Such beautiful animals! Megan (off-panel): I guess... [Same setting as in the first panel but Megan is pointing left past the Sphere.] Sphere: Now we've got time travel, so I'm here to see one for myself! Megan: Sure! There's one over there! [The Sphere floats over a leafless branch sticking out of the ground. A spider web is strung between the left border of the panel (four spokes) and the branch (three spokes). A spider (almost as large as the Sphere) sits in the center of the web. Megan answers it from off-panel.] Sphere: Woowwww! Sphere: What's that giant net it's caught in? Megan (off-panel): You mean its web? Sphere: Its what? [Same setting as in the first panel.] Megan: Oh, right, fossils. So you wouldn't know about... [In a frame-less panel only Megan is shown facing left while she ponders. Beat panel.] Megan: ... [Again a scene similar to the first.] Megan: Oh my God. Dinosaurs must have been so weird . Cueball: Holy crap, yeah. Megan: Listen, can we borrow your time machine?

This Monday comic was the first in a series of two comics that continued in the next release 1748: Future Archaeology on Wednesday. Both comic in this series have titles of a noun followed by a field of research. A time-traveler (the black floating energy Sphere) visits the present day from the far future. Spiders are the Sphere civilization's current craze, just as dinosaurs are currently our craze. The Jurassic Park media franchise began with the first film in 1993 and the year before the release of this comic in 2016, the fourth movie Jurassic World were released with at least one more film in development. We also have theme parks and kids dressing up as dinosaurs. The time-traveler arrives in the presence of Megan and Cueball , and tells them who it is and why it is here, to see spiders which they learned about through fossils (See the explanation of the next comic about the strange fact that it speaks English). Megan points it towards a spider sitting in its web; the Sphere is awestruck to see the object of its obsession in the living flesh, but seeing it sitting in it's web, the Sphere asks why it has been caught. Megan realizes that because it only knows about spiders from fossils, it could come as a big surprise that the spiders sit in their webs like this. Spider silk does in fact fossilize in amber (and most fossils of spiders are also found in amber because the soft body of a spider does not easily petrify ). The reason we know that silk threads in amber are the spider's web is because we can compare fossils with the spiders of today. If not for the fact that we knew about spiders' webs in advance, it would be hard to say if we would have made the connection from the amber fossils. The Sphere is thus surprised to see the spider in a web since they had not understood any possible hint of spider webs in the fossil records, from which the Sphere's civilization gathered all their knowledge of spiders. Spiders have been on Earth at least for 380 million years and are still thriving and more than 40,000 species are known. With our current knowledge, we know that webs are an essential part of a spider's life. Making sense of a spider's life is practically impossible without including their webs. However, the future-people have done just that until now; discovering how wrong they are is bound to become an intense experience for them. It should be noted that there have been multiple present-day discoveries of fossilized spiders' webs preserved in amber - however, since fossils forming like this is a rare event, it is quite possible that none would have been found by the future-people. Megan immediately connects the fact that the Sphere did not know about spider webs to our current understanding of dinosaurs: If a future civilization thinks they understand spiders based on fossils, while missing something as essential as their web, what is the human civilization missing about dinosaurs? Cueball quickly catches on, and Megan asks if they can borrow the time-machine to experience their own revelations about dinosaurs just like the revelation the Sphere has just had about spiders. The title text calls back to one of Randall's favorite facts (see 1211: Birds and Dinosaurs ) - that birds are technically part of the clade Dinosauria . Birds do lots of weird stuff - like starlings flocking , the dances of birds of paradise , lyrebird mimicry or petrels puking stomach oil . Randall says that for every time a birds does something weird then it is likely that dinosaurs would have had equally strange behaviors, and birds are only a small subset of all dinosaurs. So there would have been even more strange behaviors among the dinosaurs than among the present days birds. It is, however, basically impossible to tell from the fossil record. All we know is that dinosaurs had features such as display feathers (like on a Peafowl (a descendant of dinosaurs)), neck frills , and crests (like on the Dimetrodon , which lived before the dinosaur with which it is not related) which likely played a role in mating and territorial shows. It is unclear what the Sphere is. Since it states that what they know about spiders comes from fossils on our planet, it seems likely that the Sphere is neither human nor from our planet. So most likely they are a space traveling species and not human. The appearance as a sphere may either be an indication that they did not travel in person but rather only look out at the past through the energy sphere, or it may be that these aliens are actually spheres, floating as energized objects in space. In that case this is an actual alien floating in front of Megan and Cueball. It seems like the Sphere's civilization already had the spider craze before they invented time travel, and they decided to use time travel the first time to go back to see real spiders on Earth. This also tells us that they are from so far into the future that there are no spiders left. Of course with climate changes etc. going on, that may not necessarily be too far into the future. As long as the human race (or knowledge of spiders) has also disappeared from Earth. But since the Sphere itself tells us that it comes from a distant future, the setting is not related to how fast humans and spiders becomes extinct. As is seen in the next follow up comic, there is very little left of our current civilization, and no records of spiders and their webs. This is the second comic with special mentioning of a science related directly to spiders, the first being 1135: Arachnoneurology . In this comic Randall manages to combine no less than three of his favorite recurring subjects with time travel , spiders and, of course, dinosaurs . [The Sphere, a time-traveler depicted as a solid floating black energy sphere surrounded by six outwardly-curved segments) seems to have materialized in front of Megan and Cueball who is in the right part of the panel facing left towards it. The Sphere looks like this except in the zoom in from panel two. A voice emanates from the Sphere.] Sphere: I'm here from the distant future! Megan: Cool! What for? Sphere: Spiders! [A close-up of the Sphere, still depicted as a black sphere, but not perfectly round at this zoom level and also clearly with some white dots in the dark area. It is also now surrounded by seven (rather than six) narrow rays with irregular dots between the rays. Megan answers it from off-panel.] Sphere: We've learned about your planet's spiders from fossils. Sphere: There's a whole spider craze. We have spider theme parks, spider movies, spider costumes... Sphere: Such beautiful animals! Megan (off-panel): I guess... [Same setting as in the first panel but Megan is pointing left past the Sphere.] Sphere: Now we've got time travel, so I'm here to see one for myself! Megan: Sure! There's one over there! [The Sphere floats over a leafless branch sticking out of the ground. A spider web is strung between the left border of the panel (four spokes) and the branch (three spokes). A spider (almost as large as the Sphere) sits in the center of the web. Megan answers it from off-panel.] Sphere: Woowwww! Sphere: What's that giant net it's caught in? Megan (off-panel): You mean its web? Sphere: Its what? [Same setting as in the first panel.] Megan: Oh, right, fossils. So you wouldn't know about... [In a frame-less panel only Megan is shown facing left while she ponders. Beat panel.] Megan: ... [Again a scene similar to the first.] Megan: Oh my God. Dinosaurs must have been so weird . Cueball: Holy crap, yeah. Megan: Listen, can we borrow your time machine?

Future Archaeology

Future Archaeology

https://www.xkcd.com/1748

https://www.explainxkcd.com/wiki/index.php/1748:_Future_Archaeology

[The Sphere, a time-traveler depicted as a solid floating black energy sphere surrounded by six outwardly-curved segments (first seen in the previous comic), is floating in front of Megan and Cueball who is walking after it towards the right part of the panel. The Sphere looks like this in all panels, but in the zoom in from panel two more details can be seen. A voice emanates from the Sphere.] Megan: Since you're from the future, do you know who wins the election? Sphere: Haven't the faintest idea. Hardly any text has been recovered from your era, so we know little about your history and culture. Sphere: We're mostly here for the spiders, anyway. [A close-up of the Sphere, still depicted as a black sphere, but not perfectly round at this zoom level and also clearly with some white dots in the dark area. It is still surrounded by six narrow rays with irregular dots between the rays.] Sphere: There are only two written accounts we've reconstructed. Sphere: We don't know whether they describe real events or myths. [The Sphere is now on the left side of Megan and Cueball who has stopped walking and has turned to look at the Sphere.] Sphere: One is a story about a man who built a boat to survive a great flood. Megan: Oh yeah. Noah. Cueball: We do like our flood narratives. [The Sphere has drifted further away from Megan and Cueball.] Sphere: The other is an account of how a man named Aaron Carter defeated a god named Shaq. Megan: That one may have been mangled a bit by the eons.

This Wednesday comic is a direct continuation of the previous comic 1747: Spider Paleontology from Monday about a time-traveler (the black floating energy Sphere) who has come back from far in to the future to see spiders (only known from fossils in their time). See 1747: Spider Paleontology for a more complete explanation of this part of the joke. This series ended with this comic. Both comics in this series have titles of a noun followed by a field of research. Since Megan and Cueball now have access to the Sphere from the future they ask if it knows who will win the election. This is a reference to the United States elections, 2016 where the very controversial Donald Trump was up against former United States First Lady Hillary Clinton , who also had several controversies going on. This comic was released about three weeks before election day. It is likely one of the most discussed elections ever, especially in the rest of the world outside the US, where especially European leaders have made it clear that they are against Trump. That was mainly earlier on, before they realized he might actually stand a chance. Of course anyone interested in any election would be interested to hear from the future how it went, but this particular election may interest a larger proportion of the world population than any prior election. (The election was the subject three weeks later the day before the election where Randall endorsed Hillary directly in 1756: I'm With Her .) Sadly for Megan and Cueball, the sphere has come back from so far in to the future, that even spiders have gone extinct. (Whether humans also have is unclear, see discussion about this in 1747: Spider Paleontology ). The Sphere makes this clear by stating that its civilization hardly know anything about our era and they know little about our history and culture. (And by the way it only came back for the spiders, anyway). The idea is that history is filtered in similar fashion to fossils. What is contemporaneously important, like a spider's web , dinosaur feathers (see previous comic), or the United States presidential election may not survive. The Sphere tells them that only two written accounts have been reconstructed (note that they are not found in their entirety). And they do not know if they even represents real events or myths. One of the two is indeed a myth, as it is about a man building a boat to survive a great flood. Megan recognizes this as being about Noah and his famous Ark from the Genesis flood narrative , as Cueball refers to. The other is a reference to a popular pop song. The joke is that, in the future, the 2000 Aaron Carter hip hop song " That's How I Beat Shaq " ( lyrics and video ) is considered as valuable a historical document when researching humans as parts of the Bible . While secular historians consider the story of the Flood to be mythical, they still use it to infer facts about the early history of the Middle East, simply because there are a fairly small number of texts surviving from that era. "That's How I Beat Shaq" is, likewise, a fictional story including some true elements; it's just that as long as there are abundant sources documenting life in the year 2000, there's no reason to consult the song in any historical context. Yet it is the latter story that the time traveler assumes to be a clearly religious one, while seeing the former as a relatively straightforward survival story. A further layer of humor is that "That's How I Beat Shaq" is an archetypal David and Goliath story—the story of David and Goliath of course being a Biblical one as well. In fact the Spheres civilization believes Shaq ( Shaquille O'Neal a professional basketball player 2.16 m (7 ft 1 in) tall) to refer to a god, which was then defeated by Aaron, a 14 year old (and rather small kid) at the time of the release of his single in 2001. He beats Shaq on the basketball court one on one, so although this is a David vs. Goliath story it is not a fight till death. But to Aaron and his basketball fan friends, Shaq is probably seen as kind of god. Megan comments that the pop song may have been mangled by the eons . The title text expands on the joke by letting the Sphere explain that the only connection they have found between their two historical documents is via the biblical story of Moses . As Moses is also one of God's chosen prophets and leaders, like Noah and Abraham before him, these two stories appear close together in the Bible, though not close together chronologically, and it would be likely that their document with the Flood story also has some parts about Moses. Moses had an older biological brother named Aaron and the Sphere's civilization has hastily concluded that Moses' brother and Aaron Carter are one and the same. According to the Bible, God parted the Sea of Reeds (commonly mistranslated as Red Sea) for Moses and the Israelites . This is often referred to, either erroneously or out of simplification, as Moses having parted the Red Sea. Along with Noah's Flood, this is one of the two major times in the Bible that God effects grand change on a body or bodies of water. The Sphere asks Megan and Cueball if it is true that Aaron (Carter's) brother Moses did part an ocean. Megan decides to refrain from trying to explain this, having already in the previous comic realized how hard it is to explain spiders to someone who is a fan, but has never heard of spider web, and thus just states yes, yes exactly. Of course according to the Bible she can say yes to the question about Moses parting the water, as long as she does not say anything about the connection with Aaron Carter. There appears to be a major flaw in the comic on the fact that the Sphere speaks perfect English, and understands Megan and Cueball. If they only have two written accounts from our time, why do they then speak English? Especially since they seem to come from another planet and are thus likely not humans (see discussion of the sphere in the previous comic). Of course if they are humans and have come from Earth (maybe traveled away), they may just have retained the English language. But given the fact that young people today probably would not understand their own grandparents' grandparents, and that the Sphere is from so long into the future that Megan calls it eons, spiders are extinct, and only two texts have survived, it should be impossible for the language to have stayed the same. Alternatively they have also recovered some video clips, but then it would be strange the Sphere did not mention this. A final solution is that the Sphere's civilization is so advanced that it can learn the language instantly by just being in the room with other beings, simply reading it from their mind. Given the fact that it seems the Sphere has come to Earth from another planet, and has the ability to travel in time, this last option may not even be so far-fetched. This comic was published the day after the what if? Flood Death Valley , thus referring indirectly to a new possible flood history. It was the first what if? post in almost three months, the longest break between two post during 2016 (and third longest of all time at the time of its release), and it thus seems realistic that there should be some kind of connection between that and this comic. A later comic ( 1750: Life Goals ) also referenced this what if? post more or less directly. In this comic Randall manages to combine no less than four of his favorite recurring subjects with time travel , spiders , politics and religion . [The Sphere, a time-traveler depicted as a solid floating black energy sphere surrounded by six outwardly-curved segments (first seen in the previous comic), is floating in front of Megan and Cueball who is walking after it towards the right part of the panel. The Sphere looks like this in all panels, but in the zoom in from panel two more details can be seen. A voice emanates from the Sphere.] Megan: Since you're from the future, do you know who wins the election? Sphere: Haven't the faintest idea. Hardly any text has been recovered from your era, so we know little about your history and culture. Sphere: We're mostly here for the spiders, anyway. [A close-up of the Sphere, still depicted as a black sphere, but not perfectly round at this zoom level and also clearly with some white dots in the dark area. It is still surrounded by six narrow rays with irregular dots between the rays.] Sphere: There are only two written accounts we've reconstructed. Sphere: We don't know whether they describe real events or myths. [The Sphere is now on the left side of Megan and Cueball who has stopped walking and has turned to look at the Sphere.] Sphere: One is a story about a man who built a boat to survive a great flood. Megan: Oh yeah. Noah. Cueball: We do like our flood narratives. [The Sphere has drifted further away from Megan and Cueball.] Sphere: The other is an account of how a man named Aaron Carter defeated a god named Shaq. Megan: That one may have been mangled a bit by the eons.

Mushrooms

Mushrooms

https://www.xkcd.com/1749

https://www.explainxkcd.com/wiki/index.php/1749:_Mushrooms

[Cueball is squatting in front of a group of four mushrooms (two tiny, one small and one large), touching the top of the nearest and largest mushroom with a finger. This mushroom has several small dots, which becomes more visible in later panels. The other three mushrooms do not appear to have these dots. Megan is standing behind him looking on.] Cueball: Mushrooms are so weird. Megan: You know, evolutionarily, they're closer to being animals than to plants. [Megan starts walking away as Cueball now leans on the ground with the hand he touched the mushroom with. Only the large mushroom is visible in this and the rest of the panels.] Cueball: ...Really? Megan: Yup! [In a frame-less panel Cueball still squats in front of the mushroom, now resting his hand on his knees.] [Cueball stands up looking down at the mushroom.] [Cueball is walking away as the mushroom makes a sound indicated with several small lines emanating from the top of the mushroom along with a regular speech line.] Mushroom: Grrrr [Cueball snaps around to look at the mushroom again, standing in a prepared state arms slightly out and legs spread out as well.]

Cueball is looking at a mushroom , contemplating how weird they are, when Megan adds another layer to their weirdness by supplying the trivia that evolutionarily , mushrooms (which are basidiomycete fungi ) are closer to the animal kingdom than to plants on the tree of life . (Note that, technically, mushrooms themselves are only the fruiting bodies of the fungi. A mushroom is only part of a fungus, in the same way an apple is only part of a tree. The majority of the fungus grows beneath the soil, in a part of the fungus called the mycelium , which is composed of root-like structures called hyphae .) Both animals and fungi are part of the opisthokont group of eukaryotic organisms, while plants are in the archaeplastida group of eukaryotic organisms with the green and red algae . This surprises Cueball, as he, like many people, is likely to think of mushrooms as plants, as they are "grown" just like other crops. Even scientists, before the 1960s, considered fungi to be 'plants'; it took DNA-based studies in the 1990s and 2000s to 'seal the deal' and place the fungi with the animals, and not the plants. But fungi do not perform photosynthesis , and therefore do not need sunlight to grow. Instead, they get their energy from other living matter, either live (parasitic mushrooms) or dead (e.g. manure; saprobic mushrooms). Edible mushrooms like Agaricus bisporus (or white mushroom) are saprobes, farmed in caves . The body plans of fungi are also utterly unlike those of plants. There are a few plants that don't do photosynthesis, such as the parasitic flowering plant Monotropa uniflora . But these plants otherwise look like, and are built like, plants, and don't look or grow at all like fungi. Ironically, many plants, both photosynthetic and nonphotosynthetic, depend on root-associated mycorrhizal fungi for their survival and growth. Megan then walks away, and Cueball, after pondering the mushroom a while further, gets up and walks away too. But as soon as Cueball has his back turned the mushroom growls after him. Cueball spins around to look back at the now again silent mushroom. This is a bit of absurdist humor; while mushrooms are technically more animal-like than plant-like, they are still so far removed from animals they wouldn't have any of the body parts needed to growl. [ citation needed ] For that matter, most animals lack the parts needed to growl. Cueball's shock and astonishment is quite justified, and maybe it was just his imagination running wild after Megan's trivia. The reader is left to wonder what Cueball's next move will be - especially, those readers who have ever felt, or indulged, the urge to stomp mushrooms. Another interpretation of the mushroom's growling is that mushrooms might be "fake" animals disguising as plants. The mushroom seems to be a plant, and acts very plantlike until Cueball looks away. The mushroom might have growled because it was planning on killing Cueball in a sort of "kill the witnesses" action. This comic might be hinting that mushrooms are evil and plotting the downfall of humanity under the disguise of "harmless" plants. Or, simply, mushrooms want to mess with other living things. The title text takes this further, by stating that mushrooms are technically a type of ghost . Maybe because they arise from decaying remains. The title text may also refer to 1240: Quantum Mechanics or 1475: Technically , suggesting caution when dealing with a statement preceded by "technically." It may also refer to the other name of Monotropa uniflora , "ghost plant" which hosts are certain fungi. The title text might also refer to the behavior of ghosts (called Boos) in the Super Mario series, in that they only act or move when the player is facing away, as does the growling mushroom. [Cueball is squatting in front of a group of four mushrooms (two tiny, one small and one large), touching the top of the nearest and largest mushroom with a finger. This mushroom has several small dots, which becomes more visible in later panels. The other three mushrooms do not appear to have these dots. Megan is standing behind him looking on.] Cueball: Mushrooms are so weird. Megan: You know, evolutionarily, they're closer to being animals than to plants. [Megan starts walking away as Cueball now leans on the ground with the hand he touched the mushroom with. Only the large mushroom is visible in this and the rest of the panels.] Cueball: ...Really? Megan: Yup! [In a frame-less panel Cueball still squats in front of the mushroom, now resting his hand on his knees.] [Cueball stands up looking down at the mushroom.] [Cueball is walking away as the mushroom makes a sound indicated with several small lines emanating from the top of the mushroom along with a regular speech line.] Mushroom: Grrrr [Cueball snaps around to look at the mushroom again, standing in a prepared state arms slightly out and legs spread out as well.]

Life Goals

Life Goals

https://www.xkcd.com/1750

https://www.explainxkcd.com/wiki/index.php/1750:_Life_Goals

[A to-do list with a caption above:] Life Goals ☐ Meet Skrillex in Phoenix ☐ Study zymurgy ☐ Get a pet axolotl named Hexxus ☐ Observe a syzygy from Zzyzx, California ☐ Port the games Zzyzzyxx and Xexyz to Xbox ☐ Publish a Zzzax/Mister Mxyzptlk crossover ☐ Bike from Xhafzotaj, Albania to Qazaxbəyli, Azerbaijan ☐ Paint an archaeopteryx fighting a muzquizopteryx ☐ Finish a game of Scrabble without getting punched

All visible goals except the last one on this to-do list feature one or more strange words containing an excess of the last three letters of the alphabet (X, Y and Z), often using several of them in the same words, even several of the same rare letter in a row. (See Table of life goals below). All of these words can be looked up in the English version of Wikipedia, but only a few are common nouns , three of them weird animal names, the rest being proper nouns , i.e. persons names (fictional or artist) or obscure names for places or video games. The first goal is the one with fewest of these letters, only using two x's, and only the first word is strange, Skrillex being the artist name of a musician. All later entries have at least three of these letters, which are most often used in very strange, often difficult-to-pronounce, words. The punchline, in the final and ninth goal, expresses that the writer of this list often uses these unexpected and bizarre words in Scrabble games, which exasperates his opponents to such a great extent that he has yet to finish a game without getting punched. All of these words would theoretically earn a player many points in Scrabble, but outside of casual play it is not allowed to use proper nouns (see Scrabble points below). In the title text, a reference is made to the fact that none of these goals have been checked off yet. It also turns out that it is indeed Randall's list, since the writer of the list did (at least) manage to check off the goal Make something called xkcd early. Sadly there are neither y's nor z's nor even more than one x in that four letter combo. This comic was published the week after the what if? Flood Death Valley , which referred directly to the city Zzyzx in one of the pictures. It's the second comic in that week after the what if? post that references it more or less directly, the previous one being 1748: Future Archaeology . It seems likely that Randall created this comic after doing research for this what if? post, and came across the city Zzyzx as the shortest way to dig a channel to flood Death Valley. All of these strange words would theoretically earn a player the prize of many points in Scrabble (Go to the table of words below). However, most of them would not be found in SOWPODS (the combined list of all words valid in either British or North American Scrabble tournaments). Also, many include too many X's, Y's or Z's (there's 1 X, 2 Y's, 1 Z in a standard set), meaning at least one would have to be substituted for a blank (which is not worth any points). Some words would also be very difficult to play in reality, since there are only 7 letters in a Scrabble hand, so they could only be played in extremely rare circumstances (there are only a couple of ways to play MUZQUIZOPTERYX: for instance, from MU and OPTER; or MU, QUIZ and ER; or an astonishingly unlikely set of crossing letters). Many are long enough that, in theory, they could net the player the additional 50 point bonus for using all seven letters in a hand if played right. [A to-do list with a caption above:] Life Goals ☐ Meet Skrillex in Phoenix ☐ Study zymurgy ☐ Get a pet axolotl named Hexxus ☐ Observe a syzygy from Zzyzx, California ☐ Port the games Zzyzzyxx and Xexyz to Xbox ☐ Publish a Zzzax/Mister Mxyzptlk crossover ☐ Bike from Xhafzotaj, Albania to Qazaxbəyli, Azerbaijan ☐ Paint an archaeopteryx fighting a muzquizopteryx ☐ Finish a game of Scrabble without getting punched

Movie Folder

Movie Folder

https://www.xkcd.com/1751

https://www.explainxkcd.com/wiki/index.php/1751:_Movie_Folder

[Black Hat is sitting in an armchair, with the right arm on the armrest and looking at his smartphone held in his left hand, when a voice from behind him (off-panel left) addresses him. It turns out in the next panels that it is Cueball.] Cueball (off-panel): Your movie folder is so weird . Where do you find all this stuff? Black Hat: Dunno. Black Hat: Around. [In an frame-less panel Cueball is seen sitting in an office chair at a desk facing left. He is looking at Black Hat's computer while typing on the keyboard which is on a shelve lower than the regular desk surface. Black Hat replies to his queries from behind him off-panel right.] Cueball: Lorem Ipsum: The Movie? Cueball: Titanic XCVIII? Black Hat (off-panel): That series gets good when they start hitting the reef created by all the previous wrecks. [Cueball leans in closer to the screen.] Cueball: Debbie Did 9/11? Cueball: Time Jam: A Connecticut Huskie on King Arthur's Court? Black Hat (off-panel): Really underrated Space Jam sequel. [Zoom in on the scene so nothing beneath the keyboard is visible. The screen and Cueballs head almost spans the width of the panel.] Cueball: Harold and Kumar Go to Howl's Moving Castle? Cueball: A Million Random Digits with 100,000 Normal Deviates? Black Hat (off-panel): That's the original-the book was a novelization. [Back to Black Hat sitting in the chair as in the first panel, but leaning a bit further back and the arm on the armrest has been moved closer to him.] Cueball (off-panel): Michael Bay's The Vagina Monologues!? Black Hat: It's pretty good, despite all the CGI explosions.

Cueball is looking through Black Hat's downloaded movies, which are all adaptations of non-literary works, improbable sequels, and/or crossovers between very disparate properties. Cueball reacts with increasing incredulity to Black Hat's collection, while Black Hat casually responds with equally unlikely (non-)explanations. Knowing Black Hat, his movie folder is deliberately weird just to provoke this kind of reaction. In the real world, there are movies which can provoke similar shock. For example, many successful films get direct-to-video (or, now, direct-to-digital ) sequels and spinoffs, often featuring none of the original cast and which get very little marketing. Therefore, someone might be surprised to know that there's an American Psycho 2 , a Starship Troopers 3 , a Dr. Dolittle 5 , or a Bring It On 5 . Randall previously made fun of the proliferation of direct-to-video sequels in What If: Twitter Timeline Height , with at least 27 Land Before Time films (in reality, there were 14). Another source of weird titles are mockbusters . When a film uses a public domain property as its basis, or a title that is too generic to trademark, other studios will simply create their own films and pretend that they're a sequel to the more famous film. Examples include Titanic II , Troll 2 , Troll 3 , the other Troll 3 , Day of the Dead 2: Contagium , Alien 2: On Earth (not to be confused with the real sequel Aliens ) and War of the Worlds 2: The Next Wave . Marketing wheezes have also produced some crossovers almost as unexpected as those in the comic — Abbott and Costello Meet Dr. Jekyll and Mr. Hyde , Scooby-Doo! WrestleMania Mystery and Jesse James Meets Frankenstein's Daughter are all real films. A similar setting with Cueball and Black Hat also discussing movies was seen in 493: Actuarial . Back then Black Hat was still reading newspapers. Black Hat has previously given similar non-answers to long series of questions from Cueball in 908: The Cloud and 1159: Countdown . Another type of comic where movie titles needs to be guessed from strange versions of the title was previously used in the Synonym Movies series. [Black Hat is sitting in an armchair, with the right arm on the armrest and looking at his smartphone held in his left hand, when a voice from behind him (off-panel left) addresses him. It turns out in the next panels that it is Cueball.] Cueball (off-panel): Your movie folder is so weird . Where do you find all this stuff? Black Hat: Dunno. Black Hat: Around. [In an frame-less panel Cueball is seen sitting in an office chair at a desk facing left. He is looking at Black Hat's computer while typing on the keyboard which is on a shelve lower than the regular desk surface. Black Hat replies to his queries from behind him off-panel right.] Cueball: Lorem Ipsum: The Movie? Cueball: Titanic XCVIII? Black Hat (off-panel): That series gets good when they start hitting the reef created by all the previous wrecks. [Cueball leans in closer to the screen.] Cueball: Debbie Did 9/11? Cueball: Time Jam: A Connecticut Huskie on King Arthur's Court? Black Hat (off-panel): Really underrated Space Jam sequel. [Zoom in on the scene so nothing beneath the keyboard is visible. The screen and Cueballs head almost spans the width of the panel.] Cueball: Harold and Kumar Go to Howl's Moving Castle? Cueball: A Million Random Digits with 100,000 Normal Deviates? Black Hat (off-panel): That's the original-the book was a novelization. [Back to Black Hat sitting in the chair as in the first panel, but leaning a bit further back and the arm on the armrest has been moved closer to him.] Cueball (off-panel): Michael Bay's The Vagina Monologues!? Black Hat: It's pretty good, despite all the CGI explosions.

Interplanetary Experience

Interplanetary Experience

https://www.xkcd.com/1752

https://www.explainxkcd.com/wiki/index.php/1752:_Interplanetary_Experience

[Caption above the panel:] Where to go on Earth to get the Interplanetary Explorer Experience [A chart with seven rows with celestial bodies on the left side of seven lines and a description on the right side. The first entry has three celestial bodies in two rows, the rest are in one row, although the last entry encompasses a list of planets. Four times the day/night side of the celestial bodies is mentioned in brackets.] Pluto, Moon (night) Mt. Everest at night Mercury (night) Moon (day) Mt. Everest at noon under a tanning lamp Mercury (day) A lava flow on a volcano at noon Venus A heat-shrink wetsuit in a blast furnace Mars Mt. Everest at sunset Titan Waist-deep in an outgassing Siberian swamp Jupiter-Neptune Jumping from a high-altitude balloon over an Antarctic Ocean winter storm

This comic lists ten celestial bodies : most other planets , the dwarf planet Pluto , as well as two moons , the Earth's Moon and Titan (the largest moon of Saturn ). It then asks what places on Earth people could go to for a real Interplanetary Experience , as if they were explorers on these planets. It turns out that none of these ten other worlds are very nice to visit... This is a parody on organizations that in preparation for future planetary exploration organize half-realistic experiments in human behavior on other planets, trying to emulate or mock-up - often on low budget - the conditions in which future explorers are to live and work. For this purpose, they build mock-up bases, habitats etc. in places that look like other planets or have the environmental conditions somewhat similar to other celestial bodies' surfaces. They seek out desolate places like deserts or polar regions for this purpose. In this comic Randall tries to identify places on Earth that actually have environmental conditions as close to these other worlds' as can be possible on the surface of the Earth. Some of the places suggested by Randall are borderline-survivable for a human, but most will kill you extremely quickly without a lot of high-tech gear - whether through severe hypothermia (freezing), conflagration (fire), crushing (high pressure), or from violent winds. Basically, nowhere in the solar system , except Earth, is even close to survivable (and there is actually only a very limited amount of Earth's surface where humans can actually live permanently). There is no planet or moon with a breathable atmosphere, or where the temperature stays within the human-tolerable range of roughly −20°C to 40°C (−5°F to 105°F, 250-310 K). It is also only with really good clothing and a place to stay at night that humans can live in a place much colder than 10°C for longer periods. The only place humans have so far ventured off-Earth is the Moon, and only during lunar morning while wearing thick pressurized spacesuits. Some celestial bodies, like Venus and Jupiter , may never be visitable by humans without either huge advances in material science or full-scale terraforming (for Venus). Some places, like the centers of any planet (for example, the gas giants or even Earth itself), will probably never be visited, even by robots. (The title text suggests what happens when falling towards the center of a gas giant). Below is a list going through the seven suggested places on Earth. Due to the low pressure and temperature on the top of Mount Everest it is mentioned no less than three times, but using different time of day to represent different celestial bodies. In the first entry it even takes care of three in one go. Two of those are the Moon and Mercury, but for both only on their night side facing away from the sun. They are thus each mentioned twice, as there is a huge difference in environmental conditions between the sunlit faces of these two and their night sides. On the other end of the temperature scale are mentions of lava and a blast furnace ; also high pressure environments are suggested to simulate other planets. The last goes for the gas giants, which are all mentioned together in the last entry. The two groupings explains why there are only seven places mentioned for ten celestial bodies. The reason that the Moon is mentioned is of course that it is the closest companion to Earth and that we have actually visited it. That the only other moon mentioned is likely because it is the only really cold celestial body that actually has an atmosphere as well as a surface humans could stand on. But there are many other large moons that would be interesting to visit, like the Galilean moons especially Europa . But that could probably be compared to being on Pluto, except the sun is a bit larger. That Pluto is included as the only dwarf planet is probably because it was still a planet when Randall was a kid (see 473: Still Raw ) and is the most recent (new) celestial body visited by a space probe at the time of release of this comic. This was celebrated by Randall in 1551: Pluto . The title text is just a continuation of the last entry about falling down through the atmosphere of a gas giant, and it is also explained in the table below. This was also explored in What If? Jupiter Submarine . The dwarf planet Pluto is a small icy rock so far away from the Sun that it practically makes no difference if it is day or night, the Sun is just the brightest star in the sky of Pluto's "day" side. But for both the Earth's Moon and Mercury (the innermost and smallest planet of the solar system ) it makes a huge difference, which is why there is both a day and a night experience mentioned for these two celestial bodies (see below). Although they are very much closer to the Sun than Pluto, this makes no difference during their night time (when they face away from Sun). They are both relatively small, rocky bodies with practically no atmosphere and relatively slow rotation. Therefore their surfaces not illuminated by the Sun will cool down to very low temperatures (around -170 °C, -290 °F, 100 K), making their nighttime hemispheres desolate, dark and cold places. Randall proposes the summit of Mount Everest (the tallest mountain on Earth) as the place that will emulate the conditions most closely. It is a rocky, desolate and cold place. Even though it is not the coldest place on Earth, it is the highest point on land, therefore it has the lowest atmospheric pressure. It cannot be compared to the near-zero pressure and 100 Kelvins conditions on the aforementioned bodies, but it is as close as you can get on Earth. The top of Mt. Everest has an air pressure just 1/3 of what it is at sea level, and the oxygen levels are so low that they are barely survivable, although a few people have reached the top without oxygen tanks , but others have died after losing their oxygen supply, making it as close as you can get on Earth to the near-vacuum found on these worlds. As explained above, Mount Everest is as good an emulation of the Moon surface at night as you can get on Earth. During the Moon's day, its surface gets about as much solar radiation as Earth at noon, because both bodies' distance from the Sun is almost the same. The Earth's atmosphere, however, stops most of the Sun's ultraviolet radiation . A tanning lamp is a device emitting mostly ultraviolet radiation for the purpose of artificial tanning ; here it is used to augment the filtered Sun's radiation in an attempt to emulate the Moon's daytime conditions better. Since the Moon does not have any atmosphere it is hard to discuss the temperature experienced on the Moon, but still the surface of the Moon reaches temperatures above water's boiling point (100°C or 212 °F) during the day with an average daytime temperature of the Moon at 107°C (224.6 °F). This effect will not be very well emulated on top of Mount Everest or even in the hottest (non-volcanic) place on Earth's surface that reaches 53.9°C (129°F) — see the what if? Flood Death Valley . Mercury's surface never quite reaches lava temperatures (if it did, it would be molten), but it gets close. At noon, Mercury's equator reaches 420°C (800°F, 700 K). Lava is a liquid usually at temperatures from 700 to 1,200 °C (1,300 to 2,200 °F, 970 K to 1470 K) but depending on what type of rock it's formed from, lava can erupt at temperatures as low as 500°C-600°C (930°F-1100°F, 770–870 K). Standing on a volcano on a partially solidified lava flow (which, it goes without saying, is incredibly dangerous) would expose you to similar temperatures. Near the poles, Mercury's surface temperature is always very low as the axial tilt is almost zero, meaning that the poles do not get much direct sunlight and their temperature is constantly below −93 °C (−136 °F, 180 K). The average surface temperature on Venus is around 470°C (870°F, 740 K) (enough to melt lead at 327 °C (620°F, 600 K), which is the usual comparison ), and the pressure is 92 bar (by comparison, pressure on earth is only about 1 bar). A blast furnace is a bit too hot — the blast itself is 900 °C to 1300 °C (1600 °F to 2300 °F, 1170 K to 1570 K), and they can reach 2000 °C — but either temperature is enough to kill you in seconds. As the blast furnace would emulate Venus' temperature but not pressure, Randall proposes that a daring volunteer wear a hypothetical heat-shrink wetsuit. A wetsuit is an elastic garment worn mostly over the whole body by swimmers, divers etc. Heat-shrink tubing is an elastic tube made of a material that shrinks when heated, used to provide extra insulation and mechanical or environmental protection in electrical and electronics work — you put a length of tubing over your wire, connector, or a joint and heat it with a hot air gun, making it shrink and crimp over your device. A hypothetical heat-shrink wetsuit worn while sitting in a blast furnace supposedly would shrink rapidly in the extreme temperature, exerting great pressure on your body, thus emulating Venus' surface atmospheric pressure. In other words, do not go to Venus! Again use Mount Everest's thin atmosphere and very cold temperatures to emulate the planet, but Mars' dusty, greenhouse-gas-containing atmosphere means it's not as cold as Mercury at night, nor as hot as the Moon during the day. Also the sun is much farther from Mars than from the Earth/Moon system, but much, much closer than Pluto, so it should be colder than the day side of the Moon. But the Sun still looks like a sun rather than a star from Mars, unlike on Pluto. The sunset will also make the sky reddish-purple, similar to the way the Martian sky often looks . Titan, the largest of Saturn moons (and one of the largest moons in the solar system) is one of the promising worlds for life. Given that its surface temperature is −180°C (−290°F, 95 K), that says a lot about how inhospitable the rest of the solar system is. The chemistry of the planet is interesting — there are lots of nitrogen compounds and hydrocarbons and the atmosphere is mostly nitrogen and methane. It has been confirmed that methane lakes exist on Titan's surface. It thus follows that there is likely also some precipitation of methane "snow", similarly to how water forms lakes and falls down as sleet on Earth. Similar compounds are produced by rotting material in swamps , hence the comparison to a cold Siberian swamp. Due to the global warming large area of the tundra in Siberia that used to be permanently locked in permafrost are now heating up enough to release these gases . It might thus be possible to end up waist deep in one of these "heated" swamp areas due to the resulting outgassing . Sadly for the global temperature this outgassing just increases the release of greenhouse gasses, making the global warming increase even faster. This may very well be the reason Randall chooses to mention it here, as another call back to recurring theme of Climate change and to the recent comic 1732: Earth Temperature Timeline . One key difference though is that on Earth, swamps are mostly water. On Titan — if they exist at all — they're liquid methane. Siberia also has some of the most extreme temperature differences on Earth, while Titan is just consistently cold. The coldest place in Siberia is the Pole of Cold , the coldest point in the Northern hemisphere having reached −71.2 °C (−96.2 °F, 202 K). Not quite Titan levels of cold, but certainly deadly enough. But in such cold places there would be no outgassing, so on Earth it is not possible to have both the cold and the outgassing. Note that it is Jupiter to Neptune thus including also Saturn and Uranus . They are under one called gas giants for a reason. All the planets are very cold and have stormy weather (Uranus is the least active, and Neptune is the most active) and extreme temperature and pressure gradients. On the edge of the atmosphere, conditions aren't much different from space, but as you fall in, the temperature and pressure rapidly increase past the freezing point (allowing clouds of ice and water). This environment is simulated by jumping out of a high-altitude balloon (low pressure and cold) and falling down into an Antarctic Ocean winter storm, a very cold and violently windy place. The storms on the gas planets can be much more violent than any storm on Earth. On Neptune the storms can reach 2,100 km/h (580 m/s, 1,300 mph), whereas the Great Red Spot of Jupiter only reaches 430 km/h (120 m/s, 270 mph). The highest wind speed on Earth (outside tornadoes ) has been measured at 408 km/h (113 m/s, 253 mph), and that was only the gusts. The title text continues the last entry in the main comic, so this explanation is also a direct continuation of the above entry. The extreme temperature and pressure gradients mentioned do not stop when the atmospheric temperature and pressure increase beyond water's freezing point. Soon the temperature reaches past the boiling point, and on up to thousands of degrees and unimaginably high pressures, increasing further until reaching the central core. The cores of Neptune and Uranus most likely consist of rock (superheated silicates, iron and nickel) or in the case of Saturn and Jupiter of liquid metallic hydrogen , where the extreme high-pressure and temperature causes hydrogen to behave like a metal. The suggested simulation of this environment is to fall into a super hot bath tub that falls into the burning engine room of a ship that is sinking, and thus is about be crushed by the water pressure of the deep ocean. This is the closest representation of the pressure and temperature conditions of the inner parts of the gas giants that can be imagined on Earth, but of course the cores of these planets are far, far more inhospitable than the scenarios mentioned above. Descending into Jupiter was also explored in the what if? Jupiter Submarine . [Caption above the panel:] Where to go on Earth to get the Interplanetary Explorer Experience [A chart with seven rows with celestial bodies on the left side of seven lines and a description on the right side. The first entry has three celestial bodies in two rows, the rest are in one row, although the last entry encompasses a list of planets. Four times the day/night side of the celestial bodies is mentioned in brackets.] Pluto, Moon (night) Mt. Everest at night Mercury (night) Moon (day) Mt. Everest at noon under a tanning lamp Mercury (day) A lava flow on a volcano at noon Venus A heat-shrink wetsuit in a blast furnace Mars Mt. Everest at sunset Titan Waist-deep in an outgassing Siberian swamp Jupiter-Neptune Jumping from a high-altitude balloon over an Antarctic Ocean winter storm

Thumb War

Thumb War

https://www.xkcd.com/1753

https://www.explainxkcd.com/wiki/index.php/1753:_Thumb_War

[Two children are sitting on their knees between a toy truck to the left and five building blocks to the right; three square blocks are stacked in a precarious tower and to the right of the tower there is one more square block which has a rectangular block leaning on it. Both children have lots of hair but the child to the left has a black hat on, so they are possibly young versions of Black Hat and Hairy. They are sitting across from each other with one hand touching the other's hand. Their thumbs can be seen sticking up above their hands.] Black Hat: One, two, three, four, I declare a thumb war. Black Hat: Five, six, seven, eight, finger guns proliferate. Black Hat: Nine, ten, eleven, twelve, digits can't protect themselves. Black Hat: Thirteen, fourteen, fifteen, sixteen, thumb U.N. won't intervene. Hairy: I don't want to play with you anymore.

Two small children, one a small Black Hat , sitting among their toys are playing thumb war . This is a common game for children, in which two players hold hands and attempt to pin each other's thumb down. The game is often started with both players chanting "one, two three, four, I declare a thumb war." In some variations, the chant continues counting up by an additional set of four, with a rhyme. Once the opening chant is complete, the game consists of trying to pin the opponent's thumb down. A pinned thumb must be held down for long enough to complete a count of four, or to complete the closing chant, "one, two, three, four, I won the thumb war". The standard concept is subverted here: Young Black Hat interprets the simulation of hand-to-hand combat with thumbs differently, comparing it with real conflict. He shows this in further lines, invented by himself. The second rhyme, "finger guns proliferate," is a pun on the finger gun gesture and describes small arms proliferation - the spread of black-market weapons which often comes with war as captured and smuggled guns make their way into the hands of paramilitary groups. Black Hat transfers this into the "thumb war universe", introducing finger guns into the thumb-to-thumb combat. The third rhyme continues the counting until twelve and mentions digits as in fingers, and states that they cannot protect themselves. This may be implying an imposition of firearms regulation or arms control as a response to the small-arms proliferation in the previous verse, or the defenseless nature of noncombatants in war. In the last line Black Hat states that, even though this thumb war goes on and on, the "thumb U.N.", the thumb war universe equivalent of the United Nations (UN), won't intervene. In real life the UN would try to put an end to a given war by using diplomatic power and has the mandate of using (blue-helmet) peace forces in war zones to put an end to violence and give out a mandate to nations so that they can intervene in some crisis on their own behalf. The thumb war game in Black Hat's version is instead a quite cynical portrayal of our world, criticizing the "might is right" mentality that is the sad reality of our globe, and the government of the world by the militarily strongest nations. The other child, who will someday turn into Hairy , meanwhile, is unnerved by all this and wants to stop playing. Since Hairy is just a normal child he is really not interested in Black Hat's realistic version of what a war really is. In the title text it seems like Hairy interrupts Black Hat's last rhyme after twenty, and finishes with his own rhyme, with "Bunny" ending in the same sound if you pronounce twenty like "twunny" as in some parts of the world. So it goes like this: Black Hat: Seventeen, eighteen, nineteen, twenty Hairy: Can't we just read Pat the Bunny? Thus Hairy requests that they do something more appropriate for children, like reading a picture book - specifically, the "touch and feel" book for small children and babies known as Pat the Bunny . It isn't clear what Black Hat would have said if not interrupted, but if twenty was indeed pronounced so as to slant-rhyme with bunny, one possibility is, "I'll annex your entire country," (which could conceivably be followed by, "Twenty-one, twenty-two, twenty-three, twenty-four. You're not sovereign anymore."). This is the second time a young Black Hat has been used. The first was in 1139: Rubber and Glue . Black Hat has continued to make Hairy uncomfortable even as an adult, for instance in 1210: I'm So Random . [Two children are sitting on their knees between a toy truck to the left and five building blocks to the right; three square blocks are stacked in a precarious tower and to the right of the tower there is one more square block which has a rectangular block leaning on it. Both children have lots of hair but the child to the left has a black hat on, so they are possibly young versions of Black Hat and Hairy. They are sitting across from each other with one hand touching the other's hand. Their thumbs can be seen sticking up above their hands.] Black Hat: One, two, three, four, I declare a thumb war. Black Hat: Five, six, seven, eight, finger guns proliferate. Black Hat: Nine, ten, eleven, twelve, digits can't protect themselves. Black Hat: Thirteen, fourteen, fifteen, sixteen, thumb U.N. won't intervene. Hairy: I don't want to play with you anymore.

Tornado Safety Tips

Tornado Safety Tips

https://www.xkcd.com/1754

https://www.explainxkcd.com/wiki/index.php/1754:_Tornado_Safety_Tips

[Beneath a large caption there are two pictures above each other to the left and a bullet list with five points to the right of the pictures. The top picture shows a black tornado beneath a white cloud. It is destroying something on the ground. To the right of the debris is a house and to the left some trees. The picture below shows Black Hat from the waist and up.] Tornado Safety Tips Avoid low-lying cool air Keep your downdrafts and updrafts from mixing Seek out warm and humid surface air layers Don't let rain-cooled air choke off your circulation Avoid letting your supercell merge with a squall line

The comic features a Public Service Announcement (PSA) poster, which generally contain public-interest messages aimed at raising awareness or steering behavior around a specific issue of concern, that in this case contains tips for tornado safety. Typically, a poster labeled "Tornado Safety Tips" would be filled with instructions for how humans can stay safe in the event of a tornado, such as "stay away from windows," "go to the lowest floor of your home," "if in the open, take shelter in a ditch," and so on, see these examples: Example 1 (with same title as comic), example 2 and example 3 . Black Hat on the other hand, has flipped this on its head by publishing a poster that contains safety tips for the tornado itself and contains information for how tornadoes can stay safe, i.e., continue to exist; see the table of tips below. The joke is that just as, for example, a "climber safety" poster is directed at climbers, the "tornado safety" poster is directed at tornadoes. It is thus in no way helpful for people who actually live in an area that experiences tornadoes or even for people that don't live in tornado-prone areas but want to be ready for their possible occurence [ citation needed ] . It is not possible to follow most of the guidelines [ citation needed ] , as they are intended for tornadoes. But the advice a human could follow would only take you towards places which can sustain tornadoes. Instead they should choose to use an app like the one in 937: TornadoGuard . The title text simply adds more tornado advice for tornadoes, bringing up the common myth about tornadoes not crossing mountains, except from the tornado's perspective. Although this is clearly not a tip for humans, the idea of tornado safety tip is yet another tips comic . Tornadoes are a recurring subject on xkcd. The tornado in this comic is similar to the picture used in the Tornado version of 1037: Umwelt . [Beneath a large caption there are two pictures above each other to the left and a bullet list with five points to the right of the pictures. The top picture shows a black tornado beneath a white cloud. It is destroying something on the ground. To the right of the debris is a house and to the left some trees. The picture below shows Black Hat from the waist and up.] Tornado Safety Tips Avoid low-lying cool air Keep your downdrafts and updrafts from mixing Seek out warm and humid surface air layers Don't let rain-cooled air choke off your circulation Avoid letting your supercell merge with a squall line

Old Days

Old Days

https://www.xkcd.com/1755

https://www.explainxkcd.com/wiki/index.php/1755:_Old_Days

[Cueball and Hairbun are standing together and Cueball is talking to her.] Cueball: What were things like in the old days? Cueball: I hear that you had to ... compile things for different processors? Hairbun: Yeah [Same setting in a slimmer panel, now Hairbun is replying.] Hairbun: To compile your code, you had to mail it to IBM. Hairbun: It took 4-6 weeks. [Close-up of Hairbun from the waist up.] Hairbun: Before garbage collection, data would pile up until the computer got full and you had to throw it away. [Same setting as in the first panel with Hairbun gesturing toward Cueball raising one hand palm up.] Hairbun: Early compilers could handle code fine, but comments had to be written in assembly. [In a frame-less panel Hairbun is seen from the front, with both arms out to the side with both hands held palm up.] Hairbun: C could only be written on punch cards.You had to pick a compact font, or you'd only fit a few characters per card. [Exactly the same setting as the first panel, but with Hairbun doing the talking.] Hairbun: C++ was big because it supported floppy disks. Hairbun: It still punched holes in them, but it was a start. Cueball: Wow.

This comic is showing a conversation between (young) Cueball and (old) Hairbun about computer programming in the past, specifically the compilers . Cueball, having a faint idea of just how difficult and byzantine programming was "in the old days", asks Hairbun to enlighten him on the specifics. Hairbun promptly seizes the opportunity to screw with his head. This later became a series when 2324: Old Days 2 was released more than 3 and a half years later. While her initial agreement that code needed to be compiled for multiple architectures is correct, Hairbun's claims rapidly grow ridiculous. Hairbun tells Cueball a tall tale about how hard it was back in the old days , making it sound like some of the programming languages used today (C, C++) were written on punch cards and that you had to ship your code in the mail to a computer company ( IBM in this case) to compile your code, which would take from four to six weeks. If there was a simple error, you would have to ship it again for another compilation. This is factually incorrect, but is plausible to those who do not have the knowledge or context to challenge it, similar to a Snipe hunt , or several other cultural myths told about things like the Tooth Fairy . It is clear from Cueball's final Wow that he falls for it. She then continues to explain more and more implausible so-called facts from the the olden days. What she says is true in that it was tough and slow to program on punch cards, which were actually used for an extended period of time. However, there is very little in the rest of Hairbun's story that accurate, except that it was a big deal when the floppy disk was invented. The comment about punching holes in floppy disks is true. However, the nature and purpose of the holes punched this way was dramatically different than in punch cards. 5.25" and 3.5" floppy disks had holes or notches in them to indicate the data capacity and it was common to punch additional holes into cheaper, lower capacity floppy disks to trick the computer into writing more data on them than specified by the manufacturer. With punchcards on the other hand, the holes themselves encoded the data so punching them was itself the act of programming. It is unclear if this was a coincidence, or intentionally included as a humorous aside to the readers who know the history as a misinterpreted truth in a sea of falsehoods. In the title text, Hairbun continues her musings on the old compiler days, stating that there was a lot of drama in those days . Specifically she references Reflections on Trusting Trust a famous 1984 paper by UNIX co-creator Ken Thompson in which he described a way to hide a virtually undetectable backdoor in the UNIX login code via a second backdoor in the C compiler. Using the technique in his paper, it would be impossible to discover the hacked login by examining the official source code for either the login or the compiler itself. Ken Thompson may have actually included this backdoor in early versions of UNIX, undiscovered. Ken Thompson's paper demonstrated that it was functionally impossible to prove that any piece of software was fully trustworthy. Hairbun claims that one of the dramas she refers to was that people tried to force Ken Thompson to retire, so everyone could stop being so paranoid about compilers. In reality, any coder who created the first version of a compiler (or a similar critical component) could inject a similar backdoor into software, so it would be false safety. Even if no one else had thought of this, then Thompson's paper was there for any future hacker to see. Though the problem was (claimed to be) solved in David A. Wheeler 's Ph.D dissertation " Fully Countering Trusting Trust through Diverse Double-Compiling (DDC) ". [Cueball and Hairbun are standing together and Cueball is talking to her.] Cueball: What were things like in the old days? Cueball: I hear that you had to ... compile things for different processors? Hairbun: Yeah [Same setting in a slimmer panel, now Hairbun is replying.] Hairbun: To compile your code, you had to mail it to IBM. Hairbun: It took 4-6 weeks. [Close-up of Hairbun from the waist up.] Hairbun: Before garbage collection, data would pile up until the computer got full and you had to throw it away. [Same setting as in the first panel with Hairbun gesturing toward Cueball raising one hand palm up.] Hairbun: Early compilers could handle code fine, but comments had to be written in assembly. [In a frame-less panel Hairbun is seen from the front, with both arms out to the side with both hands held palm up.] Hairbun: C could only be written on punch cards.You had to pick a compact font, or you'd only fit a few characters per card. [Exactly the same setting as the first panel, but with Hairbun doing the talking.] Hairbun: C++ was big because it supported floppy disks. Hairbun: It still punched holes in them, but it was a start. Cueball: Wow.

I'm With Her

I'm With Her

https://www.xkcd.com/1756

https://www.explainxkcd.com/wiki/index.php/1756:_I%27m_With_Her

[Inset: Eleven characters are drawn around a huge H with a rightwards arrow as the horizontal bar connecting the two vertical towers. Ponytail stands on the left with a raygun looking leftwards. Behind her is Black Hat who looks at a girl that might be Danish or Megan (but with longer hair than Megan typically has). She is flying a kite above the first two characters. Behind her and looking up at the kite is White Hat. The H is right behind him, and on top of the left tower sits Blondie looking straight out at the reader with her legs dangling over the edge and her arms resting on her knees. On the arrow sits Megan leaning against the left tower, also dangling her legs over the edge and arms resting on her knees. Cueball stands to her right by the right tower. On top of the right tower sits Hairbun with glasses looking straight right with her legs dangling over the edge one arm resting on a knee and leaning back on the other arm. On the right side of the H is an adult version of Science Girl holding a hand out towards the squirrel which Beret Guy is holding out in both arms towards her. Another Cueball stands on an office chair on the right brandishing a sword looking rightwards. He keeps his balance by holding his other arm out behind him. Caption] I'm with her. [Centred] How to help Vote―iwillvote.com Get a ride to the polls―drive2vote.org If you're having problems voting―866-OUR-VOTE Experimental social turnout project―civicinnovation.com App Store: VoteWithMe Reminder: If you're in line when the polls close, they have to let you vote.

In this serious, no joke , comic released the day before the 2016 United States presidential election (which was more contentious than most, due in part to many people finding both candidates unusually distasteful), Randall urged his American viewership to vote, and showed his endorsement for Hillary Clinton , the Democratic nominee in the election. She was up against the Republican nominee Donald Trump , who ended up winning. For the sake of completeness, it should be mentioned that there were also nominees from other parties, including Green Party nominee Jill Stein , and Libertarian nominee Gary Johnson . Neither hoped to garner enough votes to become president, but there was a chance they could affect the result in some states (no third-party candidate has won a state since 1968 , and it did not occur this time either: the closest any came in 2016 was independent candidate Evan McMullin in Utah.) It was the second time Randall referred to this election, the first being 1748: Future Archaeology three weeks before the election, but here it was just a wish to know the result using time travel (of course he did not learn the result back then…). The "H" with an arrow was Clinton's campaign logo, and I'm with her an official slogan that was widely used by her supporters, hence the title. Randall then lists tips to help you cast your vote ( see table below ) suggesting a personal investment in the election. Clinton herself may be represented by Blondie sitting on top of the H looking out at the reader as the only of the 11 characters. The only type of joke in the comic is the chosen characters. Two with weapons flank the left and right side looking out ready to defend against Trump: Ponytail with an emp gun (that she also wielded in 322: Pix Plz for melting computers of persons who make snide remarks at women, clearly a reference to allegations of Donald Trump's sexual harassment of women in general and especially to his grab them by the pussy comment ) and Cueball with his sword (from 303: Compiling ). See more details in the character gallery below. This is the first time Randall has used a comic to directly support a presidential campaign, although he did endorse Barack Obama in 2008 on his Blag . At that time, Randall wrote that he was troubled by Hillary Clinton's "basic lack of integrity", which is interesting considering he later endorsed her. He wrote later that it was very controversial when he endorsed Obama, but that it was not the most controversial comic he had published at that time. This comic might take that prize now, given that this was one of the most discussed elections up to its time. This is particularly noteworthy outside the US—for example, some European leaders openly opposed Trump, while others supported him. There were also reports of Russian hackers attempting to influence the election. Randall's support for Hillary Clinton may have been due in part to Donald Trump being a prominent climate change denier . Randall has published comics opposing climate change denial such as this: 1732: Earth Temperature Timeline , published less than two months before the election, as well as several other comics on climate change . Also Trump beating Clinton made Randall's regex that matches the last names of elected US presidents but not their opponents impossible to update. All the information on the bottom half of the comic includes sites, numbers, info, etc., current as of 2016, that are intended to help US voters to vote, regardless of whom they vote for. Including this information can assist voters who don't understand the process, don't feel that it's worth it, or feel intimidated or threatened. In general, these sites and numbers were likely included to help boost voter turnout. The title text, "We can do this", refers to Randall's desire to unite Democratic voters and elect Hillary Clinton to the White House instead of Trump. One can buy T-shirts with the famed " We Can Do It! " logo from the Rosie the Riveter wartime poster, but with Hillary Clinton in the famed position. Both resemble the former president Barack Obama 's campaign slogan Yes We Can and German Chancellor Angela Merkel 's " Wir schaffen das " (We can do this) refrain during the Syrian War refugees influx the year earlier—like Clinton, Merkel was fighting against a populist nativist movement that wanted to close the country's borders. Unfortunately for Randall, these efforts were in vain, as Donald Trump was elected on Tuesday, November 8. This result became a fact less than two weeks before the first ( 1761: Blame ) of several sad comics that all seemed related to the election of Donald Trump. Trump was never mentioned in these directly sad comics, and it took more than two years before his full name was finally used in xkcd in 2137: Text Entry in April 2019. Here it was remarked that the fact that Donald Trump was president was the weirdest thing of 2019. The list of things that can help is all about getting people to vote. While Randall is likely to have wanted to boost voter turnout regardless of political leanings, it's clear from his endorsement of Clinton that he believed increased turnout would have helped her win the race. There is general evidence that certain more heavily Democratic-leaning demographics are less likely to vote, and in this election in particular, the various political issues that had been raised against Hillary (such as the FBI's public disclosures of its investigation into her use of a private email server) were shown to have reduced enthusiasm among Democrats. But all these issues aside, both Republicans and Democrats alike agree on encouraging everyone to vote, and Randall is likely to have agreed with that sentiment as well. Here is Randall's list of suggestions for how to help Hillary Clinton win the election: The comic shows a gallery of 11 xkcd characters including all the main characters from xkcd (except Hairy ), which stand united behind Randall and Clinton despite their lack of agreement in many other comics. Note that the two characters at either side of the comic wield weapons pointing out, defending the other nine. Those next to the characters with weapons are doing recreational things like kiting and admiring adorable squirrels, both of which are recurring subjects in xkcd. [Inset: Eleven characters are drawn around a huge H with a rightwards arrow as the horizontal bar connecting the two vertical towers. Ponytail stands on the left with a raygun looking leftwards. Behind her is Black Hat who looks at a girl that might be Danish or Megan (but with longer hair than Megan typically has). She is flying a kite above the first two characters. Behind her and looking up at the kite is White Hat. The H is right behind him, and on top of the left tower sits Blondie looking straight out at the reader with her legs dangling over the edge and her arms resting on her knees. On the arrow sits Megan leaning against the left tower, also dangling her legs over the edge and arms resting on her knees. Cueball stands to her right by the right tower. On top of the right tower sits Hairbun with glasses looking straight right with her legs dangling over the edge one arm resting on a knee and leaning back on the other arm. On the right side of the H is an adult version of Science Girl holding a hand out towards the squirrel which Beret Guy is holding out in both arms towards her. Another Cueball stands on an office chair on the right brandishing a sword looking rightwards. He keeps his balance by holding his other arm out behind him. Caption] I'm with her. [Centred] How to help Vote―iwillvote.com Get a ride to the polls―drive2vote.org If you're having problems voting―866-OUR-VOTE Experimental social turnout project―civicinnovation.com App Store: VoteWithMe Reminder: If you're in line when the polls close, they have to let you vote.

November 2016

November 2016

https://www.xkcd.com/1757

https://www.explainxkcd.com/wiki/index.php/1757:_November_2016

[Caption above the panel:] The November 2016 Guide to making people feel old [A chart with a list of items to be put into the two first lines above the chart. First there are a line using the first column, then there are two lines using the second column. Below those lines are the two columns with underlined captions above. Between the columns are a long line connecting the two.] If they're [age], you say: "Did you know [thing] has been around for the majority of your life?" Age Thing 16 Grand Theft Auto IV 17 Rickrolling 18 Aqua Teen Hunger Force Colon Movie Film for Theaters 19 The Nintendo Wii 20 Twitter 21 The Xbox 360, xkcd 22 Chuck Norris Facts 23 Opportunity's Mars Exploration 24 Facebook 25 Gmail, Pirates of the Caribbean 26 In da Club 27 Firefly 28 The War in Afghanistan 29 The iPod 30 Shrek , Wikipedia 31 Those X-Men movies 32 The Sims 33 Autotuned hit songs 34 The Star Wars prequels 35 The Matrix 36 Pokémon Red&Blue 37 Netflix, Harry Potter , Google 38 Deep Blue's Victory 39 Tupac's Death 40 The last Calvin and Hobbes strip 41 Toy Story >41 [Don't worry, they've got this covered]

This is yet another comic designed to make people feel old , following soon after the last one 1745: Record Scratch . Not so long ago a comic with the very title of the largest bold letters in the caption above the panel was released: 1686: Feel Old . The next comic about feeling old, was released 11 months later, with a similar title, which is special in itself, 1898: October 2017 see more on both title and this follow up comic in the trivia section below. Specifically this comic contains The November 2016 Guide to making people feel old . (The unusual title for the comic indicates that it only works during this month). It lists ages between 16 and 41 and links each age to one or more events that happened approximately half that age ago, so 8 years ago for the 16 years old and 20 years ago for the 40 years old etc, which means that a person of that age would have had the mentioned thing in their life for the majority of their life. And then it explains that to make a person of a given [age] feel old, look up the [thing] (or things) connected to it, and say: "Did you know [thing] has been around for the majority of your life?" As an example the age 21 can be used, as it list both the Xbox 360 as well as this comic, xkcd itself. The two possible sentences would then be: "Did you know that the Xbox 360 has been around for the majority of your life?" "Did you know that xkcd has been around for the majority of your life?" This matches earlier attempts to make people feel old by mentioning how long ago it was that, for instance, a movie comes out as was the case in 891: Movie Ages . (But on this exact day when the comic was released there might have many people who did already feel old and tired - see trivia ). When an event seems to have occurred recently to you, like seeing a movie when you were twenty (with Toy Story ) and then suddenly realizing that this was 21 years ago, you will very likely feel old. Since humans' perception of time is not related to how much time has actually passed but rather to important memories, then memories like seeing the first feature-length fully computer-animated movie ( Toy Story ) makes a big impression and may stay vivid in peoples' memories. When they then, after hearing the sentence from this comic, realize that more than half their life has passed since that event, they realize how much time has passed and that makes them feel old. This is why it affects a 20-year-old to hear that Twitter is ten years old, where this will not have the same impact on a 16-year-old, since they were so young when it came out that they probably feel like it has been around for ever, and you do not feel old by hearing, for instance, something like that the TV was invented before you were born. It thus makes sense to pick something that happened almost midway through a person's life, because they then realize they are now double as old as when they first heard of Twitter. Of course also many ten years old would not have been active on Twitter when it was released, so it may not have that big an impact on those 20 years old today. The joke at the end is that people over 41 don't need anything to make them feel old, because they already feel old. He thus teases people above 41 years old by claiming they are old, although many people (above 40) would claim you are not old before you retire. This trick was also used to cap the above mentioned 891: Movie Ages to 35 years old, stating anyone as older was already old. But that comic was also released five years ago, and now Randall is himself closing in on 35 at 32 years at the time of this comics release. So he pushed the limit 6 years further, probably for this reason. Now he no longer thinks people at 36 are too old to try to make them feel old. It may be a coincidence, but still interesting, that he stopped the list just before 42, a number Randall has referred to many times in relation to it being the " Answer to the Ultimate Question of Life, the Universe, and Everything " in the Hitchhiker's Guide to the Galaxy . The title text points out that the same chart can be used for the same person once they are twice as old. So it urges the user to note down the age of the person it was used on, and then wait until their age reaches double that. So for a 16-year-old that would only be 16 more years until they are 32, but for a 41-year-old it would have to wait until they are 82 years old. When showing them this chart, they will realize that this has existed for half of their life and again have the same type of "feeling old" that this comic is supposed to instigate today.(It will work better if they still remember the joke made on them those many years ago)... [Caption above the panel:] The November 2016 Guide to making people feel old [A chart with a list of items to be put into the two first lines above the chart. First there are a line using the first column, then there are two lines using the second column. Below those lines are the two columns with underlined captions above. Between the columns are a long line connecting the two.] If they're [age], you say: "Did you know [thing] has been around for the majority of your life?" Age Thing 16 Grand Theft Auto IV 17 Rickrolling 18 Aqua Teen Hunger Force Colon Movie Film for Theaters 19 The Nintendo Wii 20 Twitter 21 The Xbox 360, xkcd 22 Chuck Norris Facts 23 Opportunity's Mars Exploration 24 Facebook 25 Gmail, Pirates of the Caribbean 26 In da Club 27 Firefly 28 The War in Afghanistan 29 The iPod 30 Shrek , Wikipedia 31 Those X-Men movies 32 The Sims 33 Autotuned hit songs 34 The Star Wars prequels 35 The Matrix 36 Pokémon Red&Blue 37 Netflix, Harry Potter , Google 38 Deep Blue's Victory 39 Tupac's Death 40 The last Calvin and Hobbes strip 41 Toy Story >41 [Don't worry, they've got this covered]

Astrophysics

Astrophysics

https://www.xkcd.com/1758

https://www.explainxkcd.com/wiki/index.php/1758:_Astrophysics

[A sign on two posts, in the grass in front of a building with windows and double doors, a window on each door, and bars facing outwards. There is a cement walk leading to the doors. On the sign is the text:] Department of Astrophysics Motto: Yes, everybody has already had the idea, "Maybe there's no dark matter—Gravity just works differently on large scales!" It sounds good but doesn't really fit the data.

In physics, the theory of gravity produced by general relativity combined with dark matter are our current best model for explaining the behavior of gravity and galaxies. The evidence supporting this model is extensive. General relativity accurately predicts the orbit of planets, even precise details like the precession of Mercury which Newtonian gravity couldn't fully explain. Dark matter, in turn, explains behaviors of galaxies such as their rotation rates that were not correctly predicted with general relativity alone. Most astrophysicists believe dark matter exists, either in the form of an unknown type of star that is too dim to see , or an undiscovered subatomic particle . However, because the concept of dark matter posits something so pervasive yet unknown and so far undetected, it can be difficult to accept, since typically inability to detect something tends to mean non-existence of that thing. One might be reminded of Aether , a similar theory that an undetectable substance exists in space to allow light and gravity to travel, although unlike dark matter that has been debunked. Thus, it is common to hear objections to dark matter, with a popular alternative idea being that dark matter can be explained away by a modified theory of gravity. One such alternative theory which gets proposed regularly is modified Newtonian dynamics (MOND). In MOND, gravity doesn't simply follow the inverse square law but has more complicated behavior. Usually, the extra behavior is either to say that gravitational force can be affected by the acceleration of the particle, or that it goes from inverse-square to just inverse at large distances. It can be appealing because it's relatively simple and seemingly more logical — it just changes our understanding of Newton's law of gravitation, rather than requiring entirely new forms of matter or unknown stars to exist — and because it has some nice side-effects, such as explaining why there seems to be a limit on the density of galaxies. Unfortunately, physicists have explored this avenue and cannot reconcile it with all existing data. One famous counterexample is the Bullet Cluster , where two colliding galaxy clusters are ripping through each other. The mass distribution within the cluster can be inferred through gravitational lensing, and appears to show dark matter and ordinary matter being separated to a certain extent which cannot be explained with MOND. Another counterexample is MOND's incompatibility with observations of the motion of galaxies in galaxy clusters. More generally, MOND isn't compatible with general relativity — which has a huge amount of experimental data in its favour — and a MOND-compatible general relativity would be very complicated and ugly. This comic illustrates physicists' exasperation for people who constantly try to challenge the existence of dark matter without considering all the evidence and theoretical foundation that support it. Apparently members of this department are so tired of hearing the same old ideas being repeated to them, that they have adopted a motto and even erected a sign in an attempt to clear the dissuation. The specific impetus for this comic may be the press coverage around this publication by Erik Verlinde (see popular description of the paper here ). It was released online three days before the release of this comic and got a lot of coverage exclaiming "this will prove Einstein wrong". While Verlinde's work on entropic gravity is a serious theory derived from thermodynamics and quantum information theory , it is important to keep in mind that it's just a pre-print and hasn't been peer-reviewed or experimentally verified yet. Verlinde's theory also doesn't match all available data - it disagrees with experimental results showing how particles interact with gravity . Thus, it is still a far cry from being a contender for replacing dark matter. The title text alludes to a similar issue faced by the Department of Neuroscience from popular misconceptions of Mirror neurons . Mirror neurons are brain cells which trigger when watching someone else do something. Experiments claim to have found mirror neurons in humans and apes, and there are theories that make mirror neurons the foundation of learning, empathy, language and consciousness itself. However, the evidence for mirror neurons is still patchy , and even if they exist, it's very simplistic to try to attribute so much of human behavior to a single type of relatively simple cell. In light of this, the motto of the neuroscientists at the department rightfully reflect their frustration. Flipping tables is a common depiction for expressing extreme outrage. It is used here also as a pun because mirrors flip the image in front of them. Another story of similar press coverage questioning the current established scientific theory was also mentioned two days before the release of this comic, on the YouTube channel Space Time from PBS Digital Studios in their video titled Did Dark Energy Just Disappear? . This one was regarding the paper Marginal evidence for cosmic acceleration from Type Ia supernovae . The video concluded that dark energy is still the best explanation. Note this is about the existence of dark energy rather than dark matter. The two are very distinct concepts. Science papers with results that supposedly disprove solidly founded theories have been the subject before in 955: Neutrinos . [A sign on two posts, in the grass in front of a building with windows and double doors, a window on each door, and bars facing outwards. There is a cement walk leading to the doors. On the sign is the text:] Department of Astrophysics Motto: Yes, everybody has already had the idea, "Maybe there's no dark matter—Gravity just works differently on large scales!" It sounds good but doesn't really fit the data.

British Map

British Map

https://www.xkcd.com/1759

https://www.explainxkcd.com/wiki/index.php/1759:_British_Map

[A black-and-white map of Great Britain. The detail on the map is minimal, showing mainly the outlines of the land, upward-pointing angles representing mountains, and points representing cities. The only other features are a small drawing of a protractor south of one peninsula, and a lake with two small sailboats on the west side of the largest landmass. The caption in the upper-right states in large letters "A BRITISH MAP," then in smaller letters underneath, "LABELED BY AN AMERICAN." Most of the map's area is covered by labels for various features, which are listed below.]

This comic is a joke similar to "How Americans see the world" showing how the average American has opinions on the world, often including jokes such as a lack of Africa , etc. This has been used before in 850: World According to Americans . The map also plays with the joke by noting it has been labeled by a specific American rather than "Americans". Many areas of the UK are most familiar to foreigners thanks to their depiction in various fantasy novels and TV series. This map labels some of these, as well as including many silly names that simply sound like real British towns to an American ear. A protractor is shown off the coast of the Mull of Kintyre in reference to the " Mull of Kintyre test " - according to urban legend, the angle of the Mull defines the maximum allowed erectness for a man on films and home video releases in the UK. Randall previously posted a map of Great Britain on his blog as part of the promotion for his book What If? . This map is from a very similar position and appears to have been traced from the same source, although there are some slight differences. Both maps include a sketch of Lake Windermere with boats on it, and both have the locations of London, Oxford and Cambridge labeled (the blog map also shows Edinburgh and Bristol - in this comic, these are labelled Eavestroughs and Minas Tirith). Both also contain references to Stonehenge and Watership Down . Note that in British English, the correct spelling of “labeled” is ‘labelled’. The title text plays around with the concept of the compass directions and how numerous regions (such as South "Sussex" and West "Wessex") incorporate such literal names in their description. Randall is creating similar sounding names which are nonsense-ish ("Norsussex" would be the region of the Northern-Southern Saxons), and placing them in relation to each other in ways which would be geographically implausible, similar to this old joke about Boston . However, in Germany there exists the region called Westphalia ( Westfalen ), and the eastern part of it is often referred to as East-Westphalia ( Ostwestfalen ), which sounds somewhat ridiculous. Part of the joke in the title text could be the fact that while three of the locations are fictional, Middlesex does actually exist. [A black-and-white map of Great Britain. The detail on the map is minimal, showing mainly the outlines of the land, upward-pointing angles representing mountains, and points representing cities. The only other features are a small drawing of a protractor south of one peninsula, and a lake with two small sailboats on the west side of the largest landmass. The caption in the upper-right states in large letters "A BRITISH MAP," then in smaller letters underneath, "LABELED BY AN AMERICAN." Most of the map's area is covered by labels for various features, which are listed below.]

TV Problems

TV Problems

https://www.xkcd.com/1760

https://www.explainxkcd.com/wiki/index.php/1760:_TV_Problems

[Cueball is sitting by his TV, holding his phone, when White Hat walks in.] White Hat: Hey, turn on the news. Cueball (Sitting on the floor in front of a computer holding a cell phone): Can't. Downloading a CD onto my phone. White Hat (off-screen): Why? Cueball: So I can use it to fix my computer's operating system enough that I can teach it to talk to my TV screen. White Hat: But then you'll be able to watch the news? Cueball: (off-screen): No. White Hat: Don't you have a computer science degree? Cueball: That just means I understand how everything went so wrong.

In this comic, Cueball has broken his computer's software so much that he is unable to "turn on the news" as requested by White Hat . Since his computer is not working at all, he is using the next best thing to download a fix: his smartphone, via a CD . This is probably one of two things: He later states that even that first step of mending won't be enough to display the news, as his computer's state is so bad that being able to send information to the TV screen is just the first step of debugging. In the last panel, he tells White Hat that his computer science degree just helps him understand how he ended up with such a terrible situation, but did not give him enough foresight to prevent the most unexpected issues. The title text clarifies this statement with a similar problem- when things start to go horribly wrong while falling from a plane, certified skydiving instructors will be able to better understand why and how bad the situation is, but won't be able to do anything if their usual tools have failed them. Besides, while they are less likely to make a fatal mistake on a given flight and fall, they are more likely to make one in their life, because of the far greater number of attempts. This is especially true considering most people never attempt a jump in their lives, giving them absolutely zero probability of dying in a skydiving accident. This also resembles 795: Conditional Risk : the more informed a person is, the more likely this person is to suffer from the issue they know about. Computers breaking in unexpected ways, and somewhat weird solutions to computer problems seems to be a thing with Cueball - and probably Randall as well. At that point, you might assume he probably enjoys it. In 1586: Keyboard Problems , he also had a problem involving both software and hardware. 1739: Fixing Problems could very well apply to this comic; Cueball may have ended with this situation while trying to correct a simple problem (eg: channels in the wrong order), and just made the situation worse every step of the way. In 456: Cautionary , he teaches his cousin about breaking fixing a computer. In this instance Cueball has his single tasking phone busy while he downloads to it and cannot interrupt what he's doing just to use the phone as a remote for the TV, although it appears more that the TV is one of the things he is trying to fix. [Cueball is sitting by his TV, holding his phone, when White Hat walks in.] White Hat: Hey, turn on the news. Cueball (Sitting on the floor in front of a computer holding a cell phone): Can't. Downloading a CD onto my phone. White Hat (off-screen): Why? Cueball: So I can use it to fix my computer's operating system enough that I can teach it to talk to my TV screen. White Hat: But then you'll be able to watch the news? Cueball: (off-screen): No. White Hat: Don't you have a computer science degree? Cueball: That just means I understand how everything went so wrong.

Blame

Blame

https://www.xkcd.com/1761

https://www.explainxkcd.com/wiki/index.php/1761:_Blame

[Cueball stands.] Cueball (thinking): I feel sad. Cueball (thinking): Bad things are happening. [Cueball still stands.] Cueball (thinking): They must be someone's fault. Cueball (thinking): But whose? [Cueball makes several thinking poses before a light bulb appears over his head.] [Close-up of Cueball's head.] Cueball (thinking): My friends on Facebook.

Cueball is blaming his "friends on Facebook " for "bad things [that] are happening". People often rant on social media sites (like Facebook) about various things which are blamed on certain people (or sometimes usually everyone), but the person doing the ranting never thinks that the problem might be with themselves. While there could be possible reasons for bad events (for example if the bad event was nobody wishing him a happy birthday or someone posting compromising pictures), his friends would not be a likely source for bad events extending beyond a personal or local scope. Most people have a few hundred (or thousand) "friends" on Facebook, most of whom do not have enough influence to cause bad events on a national or global level. [ citation needed ] The title text refers to people venting. The humorous assumption here is that one will feel better after doing so. While some amount of venting might help to relieve stress caused by bad events, alienating people you know by blaming them for bad events usually causes more stress in the long run. [Cueball stands.] Cueball (thinking): I feel sad. Cueball (thinking): Bad things are happening. [Cueball still stands.] Cueball (thinking): They must be someone's fault. Cueball (thinking): But whose? [Cueball makes several thinking poses before a light bulb appears over his head.] [Close-up of Cueball's head.] Cueball (thinking): My friends on Facebook.

Moving Boxes

Moving Boxes

https://www.xkcd.com/1762

https://www.explainxkcd.com/wiki/index.php/1762:_Moving_Boxes

[A bunch of cardboard boxes stacked up, each labeled] Contents: Grids Bison Checkerboards Fog Contents: Beacons Elves Sand Contents: Hemoglobin Contents: Water Hooves Contents: Shorebirds Contents: Oil Vectors Silt Contents: Membranes Shards Contents: Shawls Glucose Kits Hydrants Particles Knots Contents: Graphite Taupe Contents: Field Lines Contents: Traps Contents: Edges Tribes Dough Contents: Dark Matter Contents: Manifolds Contents: Triangles Peat Crowns Contents: Scrolls [Caption below the panel:] I always forget to label my moving boxes until they're sealed up and I've forgotten what's in them.

Randall talks about moving boxes and not labeling them until he forgets what's in them. Since he doesn't know what's in them, he writes silly things on the boxes as a joke. Some things are unusual/unlikely (e.g. sand, hydrants, peat) and some are abstract/impossible (e.g. elves, taupe, dark matter). Several of the categories overlap confusingly; for instance, "sand" and "silt" and "dark matter" are all generally considered as "particles"; "membranes", "edges", and "shawls" are all kinds of "manifolds"; "hooves" are part of "bison"; "fog" contains "water"; and "triangles" consist of three "edges". Another way to interpret this comic is that Randall actually has these items (or at least some of them) in the boxes and has simply forgotten which boxes contain what. According to the title text, when Randall remembers that he is calling movers, he frantically scribbles "Normal House Stuff" on all the boxes. He says this makes the situation worse, possibly because the movers see the scribble and become suspicious. Alternatively, labeling every box with the exact same phrase will make it even harder to figure out what they contain and where they should go in the new dwelling. [A bunch of cardboard boxes stacked up, each labeled] Contents: Grids Bison Checkerboards Fog Contents: Beacons Elves Sand Contents: Hemoglobin Contents: Water Hooves Contents: Shorebirds Contents: Oil Vectors Silt Contents: Membranes Shards Contents: Shawls Glucose Kits Hydrants Particles Knots Contents: Graphite Taupe Contents: Field Lines Contents: Traps Contents: Edges Tribes Dough Contents: Dark Matter Contents: Manifolds Contents: Triangles Peat Crowns Contents: Scrolls [Caption below the panel:] I always forget to label my moving boxes until they're sealed up and I've forgotten what's in them.

Catcalling

Catcalling

https://www.xkcd.com/1763

https://www.explainxkcd.com/wiki/index.php/1763:_Catcalling

Offscreen: Hey! Are you messing with the Universe Control Console!? Megan: [standing at a control panel with a small lever and what appears to be a display] It's cool. Just gotta fix one thing. [Megan still at the control panel; now a mouse pointer appears] [Megan still at the control panel; "Catcalling" appears written at the top of the panel above a dropdown menu that says "Harasses women"; the pointer is hovering over the arrow] [Megan still at the control panel; The dropdown menu is expanded to show two elements: "Harasses women" and "Attracts cats". The pointer is hovering over "Attracts cats", which is highlighted]

" Catcalling " refers to the act of whistling or shouting to express sexual interest in a person, and often constitutes harassment. Annoyed by this practice, Megan alters the Universe Control Console to create a setting in which catcalling actually attracts cats (as the name implies), thus resulting in the catcaller being harassed by the overwhelming feline presence, instead of the other way around, likely in an attempt to discourage the act. When read without the title text, it could be assumed that Megan is trying not to punish catcallers, but to turn catcalling into a positive thing, since after the change is made catcalling will no longer offend women and instead attract the attention of cats, an animal many people on the internet find cute. [ citation needed ] It is only with the clarifying information in the title text that it becomes clear that Megan is trying to punish catcalling, thus changing the joke. It is interesting to note that changing what women find insulting/harassment would involve fundamentally changing their psychology on some level. How exactly the Universal Control Console will make them immune to this specific behavior is unclear. The Universal Control Console is an intentionally ambiguous device, but based on how Megan and Ponytail used it in 1620: Christmas Settings , it can be implied to change people's memories of what reality was like before a change, so using the catcalling example, it might make everyone in the universe forget what catcalling initially was, thus removing the insult of even trying to do it in the first place. The "Universe Control Console" was introduced in 1620: Christmas Settings as the "Universe Control Panel", where it was used to control aspects of reality related to Christmas. Based on the name, it is presumed all aspects of reality could be altered using this fictitious device. The pointer arrow and menu options shown above Megan appear to depict aspects of the user interface that Megan is seeing. In 2240: Timeline of the Universe someone hit the inflation switch starting the inflation again. And then someone stopped this by hitting the emergency stop. These must also be on the Universe Control Panel. The Console appears to have been modified/upgraded since its last appearance and features fewer controls while gaining a joystick in this incarnation. It also appears that Megan has learned to operate the console better since first encountering it. ( Ponytail , who first demonstrated the console to Megan, could be the offscreen voice in this comic.) Furthermore, the title text suggests that catcalling now attracts all cats within two miles for an entire year. The prospect of being piled in cats for a year would discourage people from catcalling by a large amount. [ citation needed ] 1156: Conditioning also persuades people to change behavior related to wildlife. The redefining of terms related to sexual harassment as more innocent things has also been discussed in 1178: Pickup Artists . Also, the cursor on the console is left-handed for some reason. Offscreen: Hey! Are you messing with the Universe Control Console!? Megan: [standing at a control panel with a small lever and what appears to be a display] It's cool. Just gotta fix one thing. [Megan still at the control panel; now a mouse pointer appears] [Megan still at the control panel; "Catcalling" appears written at the top of the panel above a dropdown menu that says "Harasses women"; the pointer is hovering over the arrow] [Megan still at the control panel; The dropdown menu is expanded to show two elements: "Harasses women" and "Attracts cats". The pointer is hovering over "Attracts cats", which is highlighted]

XKCDE

XKCDE

https://www.xkcd.com/1764

https://www.explainxkcd.com/wiki/index.php/1764:_XKCDE

Installing the xkcd development environment [Inside a frame three instructions are shown:] 1. Spin up a VM 2. Spin up a VM inside that VM 3. Continue spinning up nested VMs and containers until you get fired

Randall has created a theoretical software environment named XKCDE (a portmanteau on xkcd and CDE (Collaborative Development Environment)), which relies on the user creating a series of nested virtual machines inside each other (creating sort of a digital version of the Droste effect ), which would likely cause extreme strain on the resources of the machine running it. This strain is explained in 676: Abstraction , at least for the normal case. "Virtual Machines" are software which pretend to be PC hardware so that a "guest" operating system can run inside of them, under a "host" operating system. Nesting VMs is the process of making a guest also be a host to yet another guest. Generally this is considered wasteful of resources, especially beyond one or two layers deep, and is not done except in a test lab for very specific purposes. "Containers" are a lighter form of PC abstraction. Instead of emulating the entire physical hardware, they only emulate the software stack sitting on top of the kernel. A containerisation tool will have its own standard library, software-stack and installed programs, but delegates all system calls to the host kernel. This is more efficient because no hardware needs to be emulated, but the disadvantage is reduced isolation between host and guest. A misbehaving guest can induce kernel crashes that take the host with them. The most well-known example of container software is Docker . Randall derives humour from repeating the nesting ad absurdum in a never-ending fractal of nested VMs, thus trapping the follower of the instruction forever, in a form of Nerd Sniping : Any external observer, such as your boss, who sees you doing this is likely to fire you for wasting company time (An outcome which is undesirable, though still better than being hit by a truck [ citation needed ] ). A software environment which disables both the machine it runs on and the user that runs it could be thought of as a useless machine. The title-text is a joke on the words root and leaf as used in abstract data structures, drawing an analogy of cutting down a tree (unplugging the root machine) scattering leaves (the nested VMs). A subtle pun is hidden in 'spinning': several tree species use spinning leaves to scatter their seeds. The autorotation due to the special shape of the leaves helps the seeds travel farther on the wind from their parent tree. Randall mixes this meaning of 'spinning' with the act of "spinning up a VM", the colloquial phrasing for starting up a new instance of a guest virtual machine. As a seed grows into a new tree where it lands, so apparently do the scattered VMs spin up new instances of themselves wherever they land. In this case, a literal interpretation would be that turning off the computer the VMs are running on would make all the VMs without any VMs running in them propagate themselves through a network and install themselves on other computers, which at the end of the day would be a very inefficient method of creating a virus. In 'normal' software development, spinning up a (single, non-nested) VM is a practice to ensure that the development environment is identical between developers, thus minimising hard-to-reproduce bugs due to local machine differences, such as unmatching library versions , locale settings or additional installed or missing software . The single VM image is shared between all developers, who each spin up their own instance on their personal workstation. In such cases, spinning up the VM is the first step in bringing up a local development environment, after which additional steps will usually instruct which programs to open, which configuration settings to change, etc. Someone got 4 levels deep with this. Installing the xkcd development environment [Inside a frame three instructions are shown:] 1. Spin up a VM 2. Spin up a VM inside that VM 3. Continue spinning up nested VMs and containers until you get fired

Baby Post

Baby Post

https://www.xkcd.com/1765

https://www.explainxkcd.com/wiki/index.php/1765:_Baby_Post

[Ponytail is looking at her phone while talking to Cueball.] Ponytail: Why did you post a The Wheels on the Bus Youtube video to Facebook six times? Cueball: Haha, whoops! My daughter was watching the tablet and must have hit something. [Cueball is talking to someone on the phone while pushing a shopping cart with a few items in it.] Phone: Hey, did you mean to post "FHFF,,,M,,,," and a link to a map of hardware stores? Cueball: I should really look up how to lock the screen. [White Hat is holding his phone while walking with Cueball.] White Hat: You just posted videos on metal-working, zip lines, and camouflage. Cueball: Uhh... [Ponytail is looking at her phone while talking to Cueball.] Ponytail: Um, you posted blueprints of the Crown Jewel rooms in the Tower of London. Cueball: Maybe we should be keeping more of an eye on her.

In this comic, Cueball is questioned about a series of posts made to his Facebook account. He explains the posts as the result of leaving his daughter (a baby, according to the title) unattended with his tablet. This is very common for parents with small children in modern times. Children tend to be fascinated with touchscreen devices, which include many entertainment options for small children (such as the mentioned " Wheels on the Bus " video). Infants also tend to experiment with such devices, and frequently open apps, post links, and make calls without intending to. [ citation needed ] This explains the first two panels: sharing the same video six times could be the result of the child repeatedly hitting the same area of the screen (such as a "share" link), and the gibberish text "FHFF,,,M,,,," could be due to the child randomly tapping on the screen, all without knowing what she was doing. The joke begins when Cueball discovers an apparent pattern in the new posts, starting with a map of hardware stores and culminating in blueprints for the Tower of London . These subjects, if they were chosen consciously by an adult, would strongly suggest the poster was planning a heist to steal the Crown Jewels , which have a reputation, based in part on several movies (for example, Minions ), for being overly complicated to steal. It is very unlikely for a baby to be capable of designing and carrying out such a plan, [ citation needed ] but it is also unlikely for these specific links to be posted all by accident. Cueball seems genuinely perplexed by the links (and presumably wouldn't have posted them if he were planning the crime himself), so the reader is left wondering what could have caused these posts, and whether Cueball and/or his daughter might know more than they let on. Cueball's suggestion of "keeping an eye" on his daughter suggests he is seriously considering the possibility that she might be an evil genius. The title text continues the joke by notifying Cueball that his flight to London is leaving soon, and an Uber driver is coming to pick him up. Since his daughter was using the tablet and he is surprised by the messages, this suggests she is in fact the mastermind who has already started executing her plan. Either she is making the journey herself (and Cueball is only receiving notifications because he has the same accounts linked to his phone), Cueball is being roped into the crime, or his daughter is deliberately making it look like he intends to steal the Crown Jewels in order to get him into trouble. [Ponytail is looking at her phone while talking to Cueball.] Ponytail: Why did you post a The Wheels on the Bus Youtube video to Facebook six times? Cueball: Haha, whoops! My daughter was watching the tablet and must have hit something. [Cueball is talking to someone on the phone while pushing a shopping cart with a few items in it.] Phone: Hey, did you mean to post "FHFF,,,M,,,," and a link to a map of hardware stores? Cueball: I should really look up how to lock the screen. [White Hat is holding his phone while walking with Cueball.] White Hat: You just posted videos on metal-working, zip lines, and camouflage. Cueball: Uhh... [Ponytail is looking at her phone while talking to Cueball.] Ponytail: Um, you posted blueprints of the Crown Jewel rooms in the Tower of London. Cueball: Maybe we should be keeping more of an eye on her.

Apple Spectrum

Apple Spectrum

https://www.xkcd.com/1766

https://www.explainxkcd.com/wiki/index.php/1766:_Apple_Spectrum

[A mapping, showing types of apples. Each apple is in a bubble]

The comic shows a spectrum of different types of apples, with Red Delicious towards the bad end of the spectrum, and Honeycrisp towards the good end of the spectrum. Although most spectra are only one-dimensional, Granny Smith is on some side branch, implying that the taste is so different from the other two that it deserves its own category. (Granny Smith apples have a distinctively tart, or sour, flavor with a subtle sweetness, and is commonly used for cooking, as opposed to the other mentioned varieties that are quite sweet and primarily eaten raw.) Randall has previously shown his disdain for Red Delicious apples in footnote 1 in this what if ; he also ranked green apples as tastier than red apples in 388: Fuck Grapefruit . The labeling of Red Delicious as "bad" compared to apples in general is perhaps unwarrantedly uncharitable; most apple trees produce fruit so bad that it is considered unfit for any purpose but fermentation. On the rare occasions that a tree naturally produces palatable apples, it is grafted onto other trees so that they will produce more of its apples instead of their own--all Granny Smiths are genetically identical. For a long time, though, in the US apples were mainly divided into three sorts. In case of the Red Delicious apples the colour, not the taste was deemed most important to the buyers which (along with the genetic variability of Red Delicious) lead to many Red Delicious apples breeds that looked great, but actually tasted bad leading to a big restructuration of the apple market. In the title text, Randall observes a common type of hypothetical question designed as a creative way to inquire about a person's preferences: If he were on a desert island with an unlimited access to something they like -- in this case, unlimited supply of any one type of apple -- what would he choose? However, Randall gives an unorthodox and unexpected answer to the typically playful hypothetical by taking it literally and questioning how such a situation would occur. How did he get stuck on the island, and how did he get a literally unlimited supply of apples? In reality, a desert island is unlikely to have an unlimited supply of any food [ citation needed ] , let alone apples. [A mapping, showing types of apples. Each apple is in a bubble]

US State Names

US State Names

https://www.xkcd.com/1767

https://www.explainxkcd.com/wiki/index.php/1767:_US_State_Names

[A political map of the United States is shown. The title reads:] Geography challenge: Name all 50 states [The state names in red text color are:] Alabama => Bandana Alaska => Alberta Arizona => Verizona Arkansas => Arkanoids California => Cafeteria Colorado => Colocated Connecticut => Connect Four Delaware => Delorean District of Columbia => District of Colubrids Florida => Fyoridor Georgia => George Hawaii => Kawaii Idaho => Idolatry Illinois => SK8RBOIS Indiana => That Other One Iowa => Iota Kansas => Candice Kentucky => Kennedy Louisiana => Loisa Maine => Spanish Maine Maryland => Maybelline Massachusetts => Masseuses Michigan => Mishy Minnesota => Minestrone Mississippi => Misstate Missouri => Mossouri Montana => mount -a Nebraska => Nebrunswick Nevada => Fallout New Vegas New Hampshire => New Hamper New Jersey => Nude Juggalos New Mexico => Namaste New York => Newark North Carolina => Sweet Caroline South Carolina => South Caroline Ohio => Oh Hi Oklahoma => Okay Oregon => Organs Pennsylvania => Pencilmania Rhode Island => Roald Dahl South Dakota => Dakota North Dakota => More Dakota Tennessee => Thennessy Texas => Hexxus Utah => Uhaul Vermont => Vermouth Virginia => Virjayjay Washington => Willwheaton West Virginia => Wyvern Wisconsin => Wainscot Wyoming => WYSIWYG

Randall has taken a map of the United States of America labeled "Geography Challenge: Name all 50 States" and filled in the states with words that sound similar to the states' names. The joke is that Randall is apparently terrible at remembering states by heart, or else that he interpreted "name" as "give a name to" and is giving each state a name similar to but different from its previous name. A similar joke is also seen in 1554: Spice Girls . Songs such as the 50 Nifty United States make these issues seem rarer, thus making it funnier. Below is the list. This also may be a play on the ambiguity of the phrase "Name all 50 states". When you are asked to "name" something, it can be a request to supply its given name or to come up with a new name for it. Randall has apparently taken the latter interpretation. He also may be playing with the distinction between an object's identity and its label, e.g., "The state of Texas (identity) is named Hexxus (label)", though you can argue that "Texas" is also a label. This comic is similar to 1759: British Map . Also note that the text at the top of the comic is not in all caps. Below are the Randall's fictional state names, next to the actual ones in parenthesis, and a short explanation for each one. Alberta ( Alaska ) Alberta is a Canadian province known for being parochial, politically conservative, and having a strong independence movement, similarly to Alaska. Arkanoids ( Arkansas ) Arkanoid is an arcade game, developed by Taito in 1986. Bandana ( Alabama ) A bandana is a large handkerchief cloth, worn either around the head or neck. Often used in Westerns. Cafeteria ( California ) A cafeteria is both a kind of restaurant and a name for a lunch room that serves food. California is large and diverse, offering a wide variety of choices. California also grows a large proportion of common vegetables available in the US ( Source ), making it a 'Cafeteria' for the country. Candice ( Kansas ) Candice is an alternate spelling of the girl's name " Candace ", which comes from the Latinized version of " kandake ," a title used in the Kingdom of Kush (an ancient African monarchy) for a reigning queen, queen consort, or queen mother; possibly used for female members of the royal family in general. Colocated ( Colorado ) May refer to computer servers located in a colocation centre , or to collocation , a linguistic term for words or terms that appear together with a frequency greater than chance. Connectfour ( Connecticut ) Connect Four is a two-player game, in which the objective is to connect four of your checkers in a row while preventing your opponent from doing the same. It has already been mentioned in 1002: Game AIs . Dakota ( South Dakota ) Setting up the joke in North Dakota. Delorean ( Delaware ) The DeLorean DMC-12 is a car, made famous as the time machine in the Back to the Future movies. District of Colubrids ( District of Columbia ) The Colubridae are the biggest family of snakes, accounting for about two thirds of the world's species. As the title text mentions, the District of Columbia, although not part of any state, is technically not a state itself, but is usually labeled on the maps like the 50 others for practical reasons. Here, Randall humorously explains the reason as people not wanting to upset the aforementioned snakes by dismissing their district for this pedantic reason. Fallout New Vegas ( Nevada ) Fallout New Vegas is a video game set in post-apocalyptic Nevada. Fyoridor ( Florida ) Possibly derived from the Russian name Fyodor, as in Fyodor Dostoyevsky . George ( Georgia ) Georgia was named for George II of Great Britain . Hexxus ( Texas ) The antagonist of FernGully . Ferngully is said to be the model for the later film Avatar . This is the second time Hexxus was mentioned in xkcd, the first occurrence being in 1750: Life Goals and the third being in 1918: NEXUS . May allude to the Texas oil industry and the state's general reputation for a lack of environmental protection. Idolatry ( Idaho ) Idolatry is the worship of a physical object as a god, forbidden in the Abrahamic religions. Iota ( Iowa ) Iota is the ninth letter of the Greek alphabet . In English, the word iota may also mean "an inconsiderable amount". Kawaii ( Hawaii ) A Japanese term for cute, commonly romanized similar to Hawaii. Not to be confused with Kauai , a Hawaiian island. Kennedy ( Kentucky ) Kennedy Fried Chicken is New York City–based fast food brand that shares its initials with KFC, which was formerly (and still conventionally) Kentucky Fried Chicken. "Kennedy" is also the name of a former US president ( John ) and two former US senators ( Robert and Ted ). Louisa ( Louisiana ) Louisa, feminine of Louis, is an Old German name meaning "famous warrior". Louisiana was named after King Louis XIV when it was founded as a French colony. Masseuses ( Massachusetts ) Women who give massages professionally. A contentious term in the therapeutic massage industry due to its appropriation by prostitutes. Randall might be making fun about how difficult he thinks it is to spell Massachusetts. Maybelline ( Maryland ) Maybelline is a make-up brand. Minestrone ( Minnesota ) Minestrone is a thick vegetable soup, originating in Italy. Mishy ( Michigan ) According to the Urban Dictionary, "mishy" means " mushy and horny at the same time ". Or it could just be a nickname, the way a lot of people's names, often children, get shortened with a trailing y (Bobby, Becky, Johnny, Suzy, Davey, Jimmy, etc.). Misstate ( Mississippi ) The word "misstate" means to state improperly. "Mis-" is also a prefix meaning "wrong," "incorrect," or simply negating. "Misstate" could be a non-state. Miss State is a university in Mississippi. This may also be a joke on the fact that Mississippi is one of the most commonly misspelled state names. More Dakota ( North Dakota ) Might be a reference to "More Dakka" , a catchphrase by Orks from the Warhammer 40000 universe which is also a page on TVTropes referring to the large-scale use of ammunition. May also allude to the idea that North Dakota is less visible in popular culture than its Southern neighbor, owing to the fact that the latter contains Mount Rushmore but the former does not have any major landmarks. mount -a ( Montana ) A command to mount all disk volumes in fstab (except for ones with the noauto flag). Mossouri ( Missouri ) The single different letter represents probably a typo (O is adjacent to I in a keyboard). This typo has about 22,000 results on Google. Alternatively, this could be an attempt to "correct" the spelling of the state name to match its non-intuitive postal abbreviation , MO, which is sometimes used as a pronounceable acronym. Or it could be a reference to Katie Mossouris . Namaste ( New Mexico ) Namaste is a Hindu greeting. Probably unabbreviated from NM (postal code for New Mexico). Nebrunswick ( Nebraska ) New Brunswick , a Canadian province. New Brunswick is abbreviated "NB" in the Canadian postal system , and "NB" was also as the postal abbreviation for Nebraska until 1969. It was then changed to "NE" specifically to avoid the confusion between the two. Nevertheless, people sometimes still use "NB" to refer to Nebraska. New Hamper ( New Hampshire ) A hamper is a large basket, often with lid, used for laundry. Also another name for a picnic basket. Newark ( New York ) The city of Newark is a suburb of New York City (NYC), and many people who live in Newark commute the 14 miles to work in NYC, however it is actually located in the state of New Jersey rather than New York. Other references: Newark Liberty International Airport (a major flight hub serving the New York metropolitan area ), the village of Newark, New York (near Lake Ontario), and Newark element14 (or simply "Newark"), the official distributor of Raspberry Pi. Possible reference to William Gibson's works. A mispronunciation of New York. Nude Juggalos ( New Jersey ) Juggalo is a name given to fans of the group Insane Clown Posse or any other Psychopathic Records hip hop group. Also shares the same initials as New Jersey. Oh Hi ( Ohio ) Oh (expression of surprise), Hi (greeting). A common utterance upon meeting an acquaintance unexpectedly. Okay ( Oklahoma ) OK is the state's abbreviation . Okay is a spelling of another abbreviation O.K., which means "yes" or "good", and has quite a few possible origins . Organs ( Oregon ) Could refer to either body parts that perform vital functions, or large musical instruments having rows of tuned pipes. Also a possible reference to Organ Trail , a retro survival video game that parodies The Oregon Trail . Pencilmania ( Pennsylvania ) Pencil Mania is a 1932 Tom and Jerry cartoon in which they pull out a pencil and proceed to draw figures in the air. Probably joking about how the first part of Pennsylvania sounds like the word "pencil". Roald Dahl ( Rhode Island ) A British writer , famous for child novels such as Charlie and the Chocolate Factory . This name does not actually rhyme well with Rhode Island. Dahl used the Norwegian pronunciation of his name (roo-ahl dahl, rather than ro-ahld dahl), as he had Norwegian parents. Because of how the pronunciation of the name has not been wildly known by readers, Randall may not have been aware of this. Sk8rbois ( Illinois ) "Skater Boys" or just "Skater Boy" if the '-ois' is pronounced the same as it is in "Illinois". Sk8er Boi is a song by Avril Lavigne . South Caroline ( South Carolina ) A further reference to song 'Sweet Caroline' by Neil Diamond, similar to 'Dakota' and 'More Dakota.' Plays on similarity between the names 'Caroline' and 'Carolina'. Spanish Maine ( Maine ) The Spanish Main was the mainland Spanish colonial possessions around the Gulf of Mexico. Also refers to the surrounding sea, as in the opening of the (children's?) song, "Sailing, sailing, over the bounding main, ...". May also refer to the USS Maine (ACR-1) , which, upon sinking, started the Spanish-American war. Sweet Caroline ( North Carolina ) A song by Neil Diamond. That Other One ( Indiana ) 'That Other One' is something someone might say if they were trying to name all the states from memory, and knew where a state was but not what it was called. Appropriate for Indiana, due to being a state with relatively few distinguishing features. Thennessy ( Tennessee ) Hennessy is a brand of cognac. Uhaul ( Utah ) U-Haul is a company that rents moving vans which are frequently decorated with scenes from places that most people have never visited. Verizona ( Arizona ) Verizon , a telecommunications company, has the shared text "Rizon" with Arizona (Ve rizon , A rizon a). Vermouth ( Vermont ) Vermouth is an Italian alcoholic beverage. Virjayjay ( Virginia ) Virginia is similar to vagina . Vajayjay is slang for vagina. Wainscot ( Wisconsin ) Wainscot is a type of wood panelling covering only the lower half of a wall. Wilwheaton ( Washington ) Wil Wheaton is an actor and writer, famous for his role as Wesley Crusher on Star Trek . Wysiwyg ( Wyoming ) Acronym for " what you see is what you get ". A reference to Types of Editors . Wyvern ( West Virginia ) A Wyvern is a mythical creature. [A political map of the United States is shown. The title reads:] Geography challenge: Name all 50 states [The state names in red text color are:] Alabama => Bandana Alaska => Alberta Arizona => Verizona Arkansas => Arkanoids California => Cafeteria Colorado => Colocated Connecticut => Connect Four Delaware => Delorean District of Columbia => District of Colubrids Florida => Fyoridor Georgia => George Hawaii => Kawaii Idaho => Idolatry Illinois => SK8RBOIS Indiana => That Other One Iowa => Iota Kansas => Candice Kentucky => Kennedy Louisiana => Loisa Maine => Spanish Maine Maryland => Maybelline Massachusetts => Masseuses Michigan => Mishy Minnesota => Minestrone Mississippi => Misstate Missouri => Mossouri Montana => mount -a Nebraska => Nebrunswick Nevada => Fallout New Vegas New Hampshire => New Hamper New Jersey => Nude Juggalos New Mexico => Namaste New York => Newark North Carolina => Sweet Caroline South Carolina => South Caroline Ohio => Oh Hi Oklahoma => Okay Oregon => Organs Pennsylvania => Pencilmania Rhode Island => Roald Dahl South Dakota => Dakota North Dakota => More Dakota Tennessee => Thennessy Texas => Hexxus Utah => Uhaul Vermont => Vermouth Virginia => Virjayjay Washington => Willwheaton West Virginia => Wyvern Wisconsin => Wainscot Wyoming => WYSIWYG

Settling

Settling

https://www.xkcd.com/1768

https://www.explainxkcd.com/wiki/index.php/1768:_Settling

Life Scorecard Times when I thought... "I'm not really happy here, but maybe this is the best I can expect and I'll regret giving it up." ...It turned out I... Should have stayed: 2 (in tally marks) Should have left sooner: thirteen (in tally marks)

This is a chart showing the outcomes when Randall was confronted with situations he wasn't happy with. It counts 13 situations which he realizes, in retrospect, he should have left sooner than he did, and only 2 situations where he should have stayed. The implication is that, in his experience, it's generally better to leave a situation you don't like, rather than stick with it in the hope that it will improve. People often stick with situations they are not happy with (a broken relationship, an unfulfilling career, a stale piece of cake) because they think sticking with the situation is better than throwing it away, and fear that they won't find something better if they leave. This is sometimes referred to as "settling", thus the title of the comic. This risk aversion can lead to people sticking with something a lot longer than they ought to if they want to be happiest. Humans' aversion to loss is common; you, being at the necessary reading level for this wiki, can surely easily recall many times when you feared to lose access to something or someone you valued. Economists and behavioral scientists refer to this behavior as the "sunk cost fallacy", more formally known as Escalation of commitment . Colloquially, this is a situation where resistance to change is justified by the amount of effort or time already expended. A proverb recognizing the error in this thinking is "Throwing good money after bad" , while a competing proverb seemingly justifying the behavior is "In for a penny, in for a pound" . The popular book "Thinking, Fast and Slow" by Daniel Kahneman details many "errors" in human decision-making, like our aversions to losses, the sunk cost fallacy, and others. The title text references a common thread in human regret, which is wondering whether we should have turned the other way when making a choice ("I would have...", "I could have...", "I should have...", et al). Randall points out that it is literally impossible to know how it would have turned out, perhaps urging readers not to regret their decisions, and to live in the moment. It also points out that the previous "scorecard" cannot be regarded as certain, since a person is not given the luxury of knowing what would have happened if they had made a different choice. Thus, one can think that they made the wrong choice and would have been better off if they had left sooner, but in actuality, it may have turned out even worse. It is impossible to know, and therefore he can't be positive that he didn't actually make the right choice in the situations where he "should have left" . Although knowing individual outcomes is impossible, and although it is difficult to separate correlation from causation when analyzing large numbers of decisions, rigorous attempts have been made. Notably, a paper titled "Heads or Tails: The Impact of a Coin Toss on Major Life Decisions and Subsequent Happiness" . The paper confirmed that "For important decisions (e.g. quitting a job or ending a relationship), those who make a change (regardless of the outcome of the coin toss) report being substantially happier two months and six months later." Life Scorecard Times when I thought... "I'm not really happy here, but maybe this is the best I can expect and I'll regret giving it up." ...It turned out I... Should have stayed: 2 (in tally marks) Should have left sooner: thirteen (in tally marks)

Never Seen Star Wars

Never Seen Star Wars

https://www.xkcd.com/1769

https://www.explainxkcd.com/wiki/index.php/1769:_Never_Seen_Star_Wars

[White Hat is facing Cueball while talking to him.] White Hat: You know the scene on the Death Star where– Cueball: Nah, I've never seen Star Wars . [Close-up of White Hat in a smaller panel.] White Hat: WHAT. [White Hat and Cueball are still facing each other.] White Hat: ...How?! Cueball: Uh, it was easy? Cueball: It was literally the default option. [Close up of Cueball. White Hat is speaking off-panel.] White Hat: But... How did you– Cueball: Not doing things is my superpower. I'm not doing an infinite number of things as we speak! [White Hat and Cueball are still facing each other.] White Hat: We have to watch it. Cueball: Nah, I'm good. [White Hat has turned away from Cueball and has his hands to his mouth to shout to people off-panel. Cueball has likewise turned away as he walks away and is speaking back over his shoulder.] White Hat: Hey everyone! This guy's never seen Star Wars! Cueball: Listen, I gotta go. [A small caption above the single panel.] Later... [Ponytail is looking down at her phone in her left hand while Cueball is facing her.] Ponytail: Wait, there's a new Star Wars ? Cueball: Oh, I've nev– Cueball: ...yeah! Excited for it! Big fan. [Ponytail holds her phone to her side, transferred to her right hand, as she and Cueball face each other.] Ponytail: What'd you think of the last one? Cueball: Uh... That Darth Vader, man. Cueball: Sure does love eating Jedi. [Ponytail and Cueball continue facing each other.] Ponytail: Haha, he sure does! Cueball (thinking): Phew. Ponytail (thinking): Phew.

White Hat tries to start a conversation with Cueball about the Star Wars space opera film franchise, which Cueball cuts short by stating that he has never seen the movies. This deeply astonishes White Hat. Because the movies are known worldwide and are ingrained into American pop culture, White Hat considers seeing Star Wars a universal experience. Cueball reasons that not having watched the films is the "default option", the option that applies if a person makes no explicit choice. In this case it means that if a person does not make the explicit choice to watch the films, then they remain in their initial state of not having watched them. It has been estimated that about 1 billion people, about 15% of the world's population, have seen at least one of the Star Wars movies. This means that about 85% of people alive today have, intentionally or otherwise, exercised that default option. Even accounting for people who have never had the option of seeing Star Wars movies (through poverty, age, country of residence, and so on), people who have not seen Star Wars are still in the majority. However, the Star Wars mythology is so frequently referenced in American popular culture [ citation needed ] that it's difficult to consume a normal media diet in the US without being exposed to enough quotes, clips, references, parodies and analogies to piece together most of the plot and major scenes of the films, even having taken no action to see them. Even without having watched it, it's reasonable that White Hat would expect Cueball to know something about the series. He is right, as it happens, since Cueball is able to recognize that " Death Star " is a Star Wars reference, and later knows that Darth Vader is a major character and that there exists something known as Jedi. When White Hat finally begins to grasp that Cueball has indeed not seen Star Wars , he declares that they must see it very soon or even immediately. When Cueball again shows a lack of interest, White Hat seemingly calls in social reinforcements to agree with him that having watched Star Wars is the norm. Cueball feels threatened by his friend's unreasonably assertive behavior and quickly removes himself from the situation. Later, Ponytail likewise wishes to start a conversation about Star Wars , this time about a new movie coming out. Based on his previous experience, Cueball reconsiders admitting to not having seen the past movies, and instead pretends to be looking forward to the new one. Ponytail then tries to continue the conversation, so Cueball bluffs with an incorrect declaration that Darth Vader eats Jedi, likely constructed from other mentions of the Star Wars characters that he has overheard throughout his life. Cueball carefully chooses his words to make it seem as if he knows what he is talking about. However, Ponytail doesn't call him out on this error, instead agreeing with it. Cueball is relieved — expressed as his thinking an onomatopoeic sigh of relief — as he believes he has guessed at an accurate piece of information and has avoided entering a similar situation to the previous one. The punchline of this part of the comic is Ponytail's identical feeling of relief, suggesting that she also hasn't seen Star Wars , and is also bluffing to hide that fact. It may be inferred that Ponytail has had similar experiences to Cueball, and now actually starts a conversation about Star Wars in order to avoid that social stigma. It might also be viewed as both of them having lost an opportunity to have a conversation with someone else who hasn't seen Star Wars , because both are afraid of how they'll be treated. The " Expanded Universe " (EU) was the term used to refer to canonical content outside of original six motion pictures, including novels, comic books, and video games, which existed in a shared continuity. After the Star Wars franchise was acquired by Disney it was announced that the "Expanded Universe" would be discontinued and rebranded as "Legends", so that the new Star Wars movies would not have to adhere to the established EU canon. The title text is a tip for people like Cueball, to help them hide deception when roped into conversations about the films. It argues that since the Jedi Prince series of novels established so many strange concepts that don't mesh with most other canon information, it makes for an excellent scapegoat to blame ill-fitting declarations on, seeing as even the most devoted, well informed fan has agreed to forget the entire series. Casually bringing up such a forgotten series might also make the bluffer out to be extremely knowledgeable about the Star Wars franchise as a whole. [White Hat is facing Cueball while talking to him.] White Hat: You know the scene on the Death Star where– Cueball: Nah, I've never seen Star Wars . [Close-up of White Hat in a smaller panel.] White Hat: WHAT. [White Hat and Cueball are still facing each other.] White Hat: ...How?! Cueball: Uh, it was easy? Cueball: It was literally the default option. [Close up of Cueball. White Hat is speaking off-panel.] White Hat: But... How did you– Cueball: Not doing things is my superpower. I'm not doing an infinite number of things as we speak! [White Hat and Cueball are still facing each other.] White Hat: We have to watch it. Cueball: Nah, I'm good. [White Hat has turned away from Cueball and has his hands to his mouth to shout to people off-panel. Cueball has likewise turned away as he walks away and is speaking back over his shoulder.] White Hat: Hey everyone! This guy's never seen Star Wars! Cueball: Listen, I gotta go. [A small caption above the single panel.] Later... [Ponytail is looking down at her phone in her left hand while Cueball is facing her.] Ponytail: Wait, there's a new Star Wars ? Cueball: Oh, I've nev– Cueball: ...yeah! Excited for it! Big fan. [Ponytail holds her phone to her side, transferred to her right hand, as she and Cueball face each other.] Ponytail: What'd you think of the last one? Cueball: Uh... That Darth Vader, man. Cueball: Sure does love eating Jedi. [Ponytail and Cueball continue facing each other.] Ponytail: Haha, he sure does! Cueball (thinking): Phew. Ponytail (thinking): Phew.

UI Change

UI Change

https://www.xkcd.com/1770

https://www.explainxkcd.com/wiki/index.php/1770:_UI_Change

[Cueball is doing something on his phone] Cueball: Ugh, I hate when apps make arbitrary changes to their UI. Cueball: Stuff I do all the time just got harder for no reason! Off-Screen Voice: Man. Off-Screen Voice: You are not gonna like getting old.

The system that sets out the way in which the user interacts with an app or program is called its "user interface" (UI). For an app, that may be the graphic design of the app, and commonly the nature and location of certain controls. Sometimes, when websites and apps are updated, the UI is modified. This is often done to make space for new features or to make what the developer considers to be an improvement, to the look or efficiency of the app. Occasionally UIs are modified with no obvious goal in mind other than to make changes to give the illusion of improvement when no new features have been added, thus making them completely arbitrary. Given that some users use some apps many times a day, users tend to learn and get used to the UI of common apps. Whether or not these changes are good in the long term, users often complain because all the workflows they're familiar with have been changed, and often the software never tells you where buttons and other options have been moved to. On occasion, these changes actually make common tasks more difficult and slower to accomplish. For example, in iOS 10 , on the quick access control panel (which formerly consisted of a single page of controls), moves the controls for music to a second page (accessed by an additional swipe). While this has a benefit of allowing more information about one's music to be displayed, it adds an additional step to the UI before one can control their music from the control panel. Changes also often require users to "unlearn" the automatic behavior they have in using the app (such as automatically moving to press a button in its old location). Old people get to see during their lifetime lots of these kind of changes to the way they did things in the past, and they often don't see the reason why they are made, since the young people who make the changes have a different cultural environment that the elderly won't "get". Also, just as young people like to complain about petty changes to apps, old people complain about the way their body starts to break down as they age. Muscle weakness makes tasks like opening doors and jars more difficult, the senses such as sight and hearing deteriorate, and mental processes such as memory and rationalization can become slower and less reliable. These have a far bigger impact on one's day-to-day ability to do tasks than a simple UI change. The comment in the title text could refer to either user interface changes or the effects of aging. As for the former, when websites and programs make unpopular changes, users sometimes start petitions to have them reverted - for example, 1.7 million Facebook users joined "Petition Against the New Facebook". Of course, they didn't get their way, and nowadays few will even remember the old Facebook layout. Cueball 's comment in the title text might refer to the fact that people naively believe that if they complain a lot about an undesired change on the UI of some app that is considered permanent, they might change it back, while in real life those complaints usually don't have any effect, just like the Facebook example given before. As for the latter, there's no human with the power to undo the effects of aging yet [ citation needed ] , and a petition to God would typically be called a prayer, rather than a petition. Scientific research on how to stop or reverse the effects of old age is ongoing, with limited successes but no indication that we're anywhere close to the ability to "change things back" by restoring an old person to full youthful vigor, nor that this will necessarily happen within the lifetime of anyone currently alive (though neither is it guaranteed not to happen [ citation needed ] , but it will take a while if it does). There has always been a market for immortality, with many historical figures seeking it through alchemy, science, or magic, but as of yet, products claiming to grant it have all been shams. Perhaps Cueball is hoping that advancing technologies will become sufficient to keep him from experiencing the negative effects of old age at all, and that complaining about the situation might improve the pace of progress. [Cueball is doing something on his phone] Cueball: Ugh, I hate when apps make arbitrary changes to their UI. Cueball: Stuff I do all the time just got harder for no reason! Off-Screen Voice: Man. Off-Screen Voice: You are not gonna like getting old.

It Was I

It Was I

https://www.xkcd.com/1771

https://www.explainxkcd.com/wiki/index.php/1771:_It_Was_I

[Emperor Palpatine, Luke Skywalker, and Darth Vader in throne room] Emperor: It was I who allowed the Alliance to know the location of the shield generator. Luke: You mean "It was me ." You're following an archaic grammar rule. [Zoomed in on Darth Vader, with the Emperor speaking off panel] Emperor: It was me who allowed the- Vader: No, my master, an archaic tone is appropriate here. The sentence sounds- [Zoomed in on Luke Skywalker, with the Emperor speaking off panel] Emperor: It was I who allowed- Luke: Come on, the accusative case is fine. Nominative pronouns are- [Zoomed in on the Emperor, with Darth Vader responding off panel] Emperor: It me Emperor: I allowed it Vader: My master, Vader: Please never say that again.

This comic starts with a scene from Return of the Jedi , with Emperor Palpatine , Luke Skywalker (drawn as an xkcd character) and Darth Vader . The original scene in the movie had a tense mood as the hero faces the villains. The comic's version of the scene, however, descends into a silly debate of grammar rules. Initially Palpatine begins saying "It was I who..." in accordance with traditional prescriptive English grammar. The verb "to be" is a copula , meaning that in a sentence of the form "A is B", both A and B are treated like the subject of the sentence. In most Indo-European languages, subjects use the nominative case ( I , he , she , and we ) while objects use the accusative case ( me , him , her , us ). This rule is still strong in languages like German, where speakers still use cases and therefore are familiar with how they work. The case system in English has almost died out, and only a few fossils of nominative case pronouns still remain. English's case system is so weak that most people have reduced the rule to " I goes before a verb, me comes after a verb or preposition". This gives the correct result in sentences like "It saw me". By extension, speakers therefore often say "It was me" ( here's a famous example from Vince McMahon ) even though this is not true to the traditional rules. Luke thinks that there's nothing wrong with this modern sense. It's possible the intent was to portray a descriptivist approach to grammar. His words could also be said to be prescriptivist in a different way, as he is objecting to Palpatine's grammar for not being modern enough. Darth Vader counters by pointing out that regardless of the grammatical correctness of "It was I", it is a set phrase with a good archaic ring to it suitable for a dramatic revelation from an Emperor. Vader and the Emperor using English archaisms has canon basis in Star Wars , with Vader asking "What is thy bidding, my master?" in The Empire Strikes Back . Historically, "thee", "thou", and "thy" were actually informal pronouns, but because they are not used in modern English, except in reciting historical works like some editions of the Bible, they are thought of as ceremonial and formal today. Using the archaic form would be more consistent with the Emperor's speech pattern. Palpatine finally decides to take a third option, and uses " it me ", a popular meme on Twitter in 2016. Darth Vader, out of embarrassment, begs him not to talk like that again. One of Randall 's themes is that grammar pedants apply rules to correct other people long after those rules have fallen out of actual usage. Luke is here being an anti-grammar-pedant, asking the Emperor to disapply the rule. See 890: Etymology for another instance of Luke failing to notice semantics. Characters concentrating on the linguistics of other characters speech while they deliver dramatic revelations, or the overall situation being already critical, is a classic joke . But characters interrupted for grammatical remarks typically ignore it or just blame the interrupter for not focusing on the important subject. Here, Randall goes one step further by having the other characters join the grammatical argument instead. The title text runs with the joke in the final panel, applying the same meme to Darth Vader's iconic quote "No, I am your father." It could be said that such a phrasing robs the moment of all gravitas, but then again, Yoda managed to coin a phrase like "Do or do not; there is no try", and still be taken seriously. [Emperor Palpatine, Luke Skywalker, and Darth Vader in throne room] Emperor: It was I who allowed the Alliance to know the location of the shield generator. Luke: You mean "It was me ." You're following an archaic grammar rule. [Zoomed in on Darth Vader, with the Emperor speaking off panel] Emperor: It was me who allowed the- Vader: No, my master, an archaic tone is appropriate here. The sentence sounds- [Zoomed in on Luke Skywalker, with the Emperor speaking off panel] Emperor: It was I who allowed- Luke: Come on, the accusative case is fine. Nominative pronouns are- [Zoomed in on the Emperor, with Darth Vader responding off panel] Emperor: It me Emperor: I allowed it Vader: My master, Vader: Please never say that again.

Startup Opportunity

Startup Opportunity

https://www.xkcd.com/1772

https://www.explainxkcd.com/wiki/index.php/1772:_Startup_Opportunity

[Around a table, sitting in a meeting, are Ponytail, White Hat, Beret Guy, Hairy, Hairbun, and Cueball.] White Hat: We've discovered that your company doesn't do anything. Beret Guy: How is that possible?! We have so many chairs! [Close up on White Hat and Beret Guy.] White Hat: You need to find an industry to disrupt. Beret Guy: An...industry? Beret Guy: Oh, yeah! Beret Guy: The zoning thing from SimCity! White Hat: No, like, a kind of business. Beret Guy: How do I find those? White Hat: I don't know. What's something you spend a lot of money on? [Beat panel showing only Beret Guy.] [White Hat, Beret Guy, Hairy, and Hairbun are shown. At left and right, respectively, parts of Ponytail's and Cueball's arms and lower bodies can be seen.] Beret Guy: You know those mysterious shops that sell you magical items, and then it turns out they're cursed, but when you go back later there's no sign the shop was ever there? Beret Guy: I get most of my stuff from those. Beret Guy: Like groceries. [Closeup on Hairy, Hairbun, and Cueball. Cueball has his hand on his chin.] Hairy: We should go. Hairbun: Wait. High-value sales, no regulation, and when customers try to complain, they can't find you... Cueball: Maybe this is the perfect startup.

Beret Guy's company , first seen in 1032: Networking , 1293: Job Interview and 1493: Meeting , returns, and its purpose is as vague as ever. Analysts, brought in to advise his company, determine that it doesn't actually serve any purpose (a problem which could ironically be attributed to business analysts in general). Beret Guy is dumbfounded, claiming that his company must do something , and takes a line of reasoning that faintly resembles the sort of logic a child might use. A child that visits an office building might conclude that an office does a lot because there are a lot of employees working inside, unaware that what really makes a successful business is how efficiently it uses its employees to deliver goods and services to the consumer, and whether said goods and services are competitive in their market (by their quality, or through advertising campaigns, or price). Now, if Beret Guy is given the benefit of the doubt, his odd statement could be taken to mean that his company has many administrators (a.k.a. chairmen); as the owner of a sufficiently large business often interacts with the department in charge of overhead, a person in his position runs the risk of becoming myopic, losing touch with the workers that actually make the business function. However, this is Beret Guy we're talking about here. He has demonstrated, time and time and time again, that he is hopelessly out of touch with reality, and this very strip shows no sign of him having gotten a firmer grasp of Earth logic. Displaying less business acumen than a child and less grounding in perspective than a CEO, he uses the number of chairs in the workplace as a yardstick for success, with no mention of his actual, human workforce. It may even be a stretch to say that a child would make the same assumption based on the number of chairs. The analysts suggest that Beret Guy find an industry to disrupt. The mention of "industry" immediately reminds Beret Guy of SimCity , where Industrial (along with Residential and Commercial) is one of the three main zone types - it allows factories and farms to develop. Disruption means coming up with a product that redefines what the market expects and leaving existing competitors in the dust (for instance, smartphones disrupted mobile, digital photography disrupted film, and air travel disrupted rail and sea travel (and is in turn being disrupted by high-speed rail)) - it's now an industry buzzword and virtually every company claims to be "disruptive". When pointed in the right direction, Beret Guy realizes that the main industry he deals with is weird disappearing shops selling cursed goods, such as the WiFi in 1812: Onboarding . This is a common trope in fantasy stories (notably Stephen King's novel Needful Things , using this exact premise), and as soon as Hairy hears about it he wants out of the building, but as his colleagues point out it also bears more than a passing resemblance to many dodgy startup companies . These appear suddenly with a lot of promotion and a marketable idea, looking for venture capital (or, a lot of times in recent times, pre-orders on Kickstarter ). However, many startups fail - either because they didn't take into account the difficulties involved in bringing a product to market, or because they were an active scam - and disappear without a trace, leaving customers either empty handed or with a buggy product that falls short of promises. As Cueball notes, these cursed shops are actually the perfect startup, at least from a moneymaking perspective. This humorously ignores the more obvious larger problem, that such a business would be impossible to create due to not actually having magical items to sell (unless, of course, one is referring to items that are sold by making unrealistic or implausible claims as to their use, which could be considered similar to "magic". This is common enough in the real world, and many such products call themselves "magic" without actually explicitly claiming to use mysterious powers of sorcery. One character could be thinking literally, and the other one figuratively). Apparently, the business may become one, if he does spend most of his money there. As with most Beret Guy comics, there are multiple layers of absurdity. For a start, the fact that he-and by extension, the rest of the cast-live in a world including supernatural shops is, while not inconsistent, still supernatural. The assertion that this is where he buys most of his materials and other products is also curious, given the shops' inherent temporary nature, as it implies either something about him causes these shops to appear, or that he is drawn to these shops instinctively. Most absurdly, he apparently purchases his food from these establishments (which may also serve as an explanation for his 'soup outlet' in 1293: Job Interview ), despite previously stating everything they sell is cursed, conjures troubling images in the mind of how exactly food would be cursed-and its effects. Perhaps this explains Beret Guy's strange powers . The title text alludes to the fact that irrespective of whether or not there is formal regulation, it is unwise to anger a group of people who have access to cursed magical items. It is easy to imagine numerous ways they could make one's life substantially worse. In 2332: Cursed Chair , Beret Guy purchases a chair from such a shop. In 2376: Curbside it is revealed that while the shops seem to require masks, they do not have curbside pickup. [Around a table, sitting in a meeting, are Ponytail, White Hat, Beret Guy, Hairy, Hairbun, and Cueball.] White Hat: We've discovered that your company doesn't do anything. Beret Guy: How is that possible?! We have so many chairs! [Close up on White Hat and Beret Guy.] White Hat: You need to find an industry to disrupt. Beret Guy: An...industry? Beret Guy: Oh, yeah! Beret Guy: The zoning thing from SimCity! White Hat: No, like, a kind of business. Beret Guy: How do I find those? White Hat: I don't know. What's something you spend a lot of money on? [Beat panel showing only Beret Guy.] [White Hat, Beret Guy, Hairy, and Hairbun are shown. At left and right, respectively, parts of Ponytail's and Cueball's arms and lower bodies can be seen.] Beret Guy: You know those mysterious shops that sell you magical items, and then it turns out they're cursed, but when you go back later there's no sign the shop was ever there? Beret Guy: I get most of my stuff from those. Beret Guy: Like groceries. [Closeup on Hairy, Hairbun, and Cueball. Cueball has his hand on his chin.] Hairy: We should go. Hairbun: Wait. High-value sales, no regulation, and when customers try to complain, they can't find you... Cueball: Maybe this is the perfect startup.

Negativity

Negativity

https://www.xkcd.com/1773

https://www.explainxkcd.com/wiki/index.php/1773:_Negativity

[Cueball walking on grass] Cueball: It's nice to get outside, away from the pain and negativity of the internet, [Cueball stops walking] Cueball: And just enjoy the cool breeze and the grass under my feet. [Cueball stands there, hands to his hips, looking to the cloudy sky] [Cueball looks down while pointing a finger at the grass behind him.] Grass: You suuuuck Cueball: Hey!

Cueball is going outside for some fresh air because he wants to escape the trolls of the Internet , which is known for hosting several hostile and unpleasant ideas and people. However, as he walks, some grass speaks up to insult him, and Cueball is upset to find that he hasn't escaped the negativity at all. (see 1749: Mushrooms which involves an unusual occurrence of a vocalizing angry mushroom). The title text expands on this, with him searching Google for how to "block the lawn". Blocking someone refers to a standard setting on websites and online services that can prevent certain users from communicating with you, but it is as yet unknown how this would work for a lawn insulting you. This is made ironic by the fact he is using the Internet to find an Internet technique (blocking) on a non-Internet object, while at the start of the comic, he just wanted to escape the Internet. The term " blocking " is actually used in lawn-care to refer to techniques where sunlight is restricted from reaching the lower parts of the grass stems and to persuade the root system to grow deeper into the soil. The negativity Cueball meets on-line is likely due to the results of the recent 2016 United States presidential election and this one was released only three days before the U.S. Electoral College voted for Donald Trump to become the 45th president of the United States, and this was still a bit exciting as there where rumors/hopes that some of the electors would not vote for Trump . (But only two changed away from Trump!) That this is likely is further supported with other recent comics. The first of these 1761: Blame is almost a prequel to this one, as it is about being sad about what happens on-line. This comic here was thus the second sad comic following the election, culminating shortly after his inauguration with a comic simply titled 1790: Sad . (See more on other depressive comics here .) Later in 1802: Phone , Cueball cannot go outside for a walk without bringing his phone as he cannot stand to be disconnected from his feed, which is the exact opposite of what he tries in this comic. Although in the title text he does try to disconnect, he then finds that this is also bad because it leads to social isolation. [Cueball walking on grass] Cueball: It's nice to get outside, away from the pain and negativity of the internet, [Cueball stops walking] Cueball: And just enjoy the cool breeze and the grass under my feet. [Cueball stands there, hands to his hips, looking to the cloudy sky] [Cueball looks down while pointing a finger at the grass behind him.] Grass: You suuuuck Cueball: Hey!

Adjective Foods

Adjective Foods

https://www.xkcd.com/1774

https://www.explainxkcd.com/wiki/index.php/1774:_Adjective_Foods

[An arrangement of labeled foodstuffs, from left to right and top to bottom:] Premium Stone-ground Bespoke, Cage-free Gourmet Fire-roasted Glazed flambé Organic All-natural Locally-sourced Artisanal, Kosher, Grade A Craft Barrel-aged Smoked Authentic Homemade Sun-dried Whole Extra Sharp Low-calorie Lite Original Flavor [Caption:] I'm trying to trick supermarkets into carrying my new line of adjective-only foods.

In this comic, Randall imagines creating food items whose labels contain only adjectives, and putting them on display in supermarkets. This is likely a jab at food market buzzwords, which usually rely on adjectives that bring up certain feelings based on how the food is "supposed to be", rather than a factual description of what the food actually is. By removing all nouns from product labels, Randall takes this trend to its extreme. The items depicted in this comic are filled with popular descriptions that make them sound appealing, but give no useful information about their contents. It is implied that some consumers who are susceptible to buzzword marketing will nevertheless purchase these products. The adjectives seen in the comic are: The title text may be a continuation of the main joke, in that Randall has removed the noun (nutrient type) which the recommended daily allowance is supposed to measure. This leaves "100%" which gives an impression of good value, but it is useless without knowing what it describes. Alternatively, it may be suggesting facetiously that the foods contain 100% of the recommended daily allowance of adjectives, given the high quantity of them in the product names. Obviously, adjectives are not a nutrient the human body needs that would normally be subject of a nutritional chart. This joke is very similar to comic 1060, Crowdsourcing , in that Randall is doing nothing, and trying to make it look like he is doing something. It expresses the opposite idea from comic 993, Brand Identity . [An arrangement of labeled foodstuffs, from left to right and top to bottom:] Premium Stone-ground Bespoke, Cage-free Gourmet Fire-roasted Glazed flambé Organic All-natural Locally-sourced Artisanal, Kosher, Grade A Craft Barrel-aged Smoked Authentic Homemade Sun-dried Whole Extra Sharp Low-calorie Lite Original Flavor [Caption:] I'm trying to trick supermarkets into carrying my new line of adjective-only foods.

Things You Learn

Things You Learn

https://www.xkcd.com/1775

https://www.explainxkcd.com/wiki/index.php/1775:_Things_You_Learn

[A simple X and Y graph, with the X labeled "how bad it is if you don't know {thing}" and ranging from "not bad" to "very bad", and Y labeled "how easy it is to grow up without learning {thing}" and ranging from "easy" to "hard" from top to bottom.] [Points on graph from top to bottom on the left side of the Y-axis:] 100 digits of pi Lyrics to We Didn't Start the Fire How to ride a bike How to escape movie quicksand Lyrics to 12 Days of Christmas TV theme songs [Points on graph from top to bottom on the right side of the Y-axis:] That cat bites are really serious and if bitten you should wash the bite and call a doctor immediately Red flags for an abusive relationship Signs for a stroke Cough into your elbow, not your hand That you have to empty the dryer lint trap Stop, drop, and roll That you have to pay taxes

This graph shows various items of information plotted by two criteria: a horizontal "How Bad Is It If You Don't Know [THING]" axis and a vertical "How Easy It Is To Grow Up Without Learning [THING]" axis. Specifically, the vertical axis measures roughly how likely the average person is to remain ignorant of a particular item. The horizontal axis measures the likelihood and severity of bad consequences arising from such ignorance. The title text describes an encounter Randall had where a cat climbed into the engine compartment of his car. It probably serves as an explanation for the seemingly out of place point on the graph about how serious cat bites are. The "two thumbs" is a reference to a well known type of jokes among English speakers. One of the most frequent forms is one person interrupting another mid-speech and asking "what has two thumbs and doesn't give a f*ck? THIS GUY!", before pointing to themselves with their thumbs. The idea is that you only direct the attention to your thumbs so that they can point back to you, though mentioning the thumbs was not actually required except as a topic change. Randall plays on an inversion of this joke as he (presumably) was bitten on the thumb might have lost a thumb or perhaps not have been able to make it at all without the intervention of the ER people. So here the "who has two thumbs", is not a deceiving distraction out of a boring conversation, and the thumbs are actually the focus of the phrase. 100% not bad: not bad at all . . . 100%>not-badness≥50%: not bad . . . 50%>not-badness≥0%: not too bad 100% very bad: very, very bad . . . 100%>very badness≥50%: very bad . . . 50%>very badness>0%: bad 100% hard: very, very hard . . . 100%>hardness≥50%: very hard . . . 50%>hardness>0%: hard 100% easy: very, very easy . . . 100%>easiness≥50%: very easy . . . 50%>easiness≥0%: easy [A simple X and Y graph, with the X labeled "how bad it is if you don't know {thing}" and ranging from "not bad" to "very bad", and Y labeled "how easy it is to grow up without learning {thing}" and ranging from "easy" to "hard" from top to bottom.] [Points on graph from top to bottom on the left side of the Y-axis:] 100 digits of pi Lyrics to We Didn't Start the Fire How to ride a bike How to escape movie quicksand Lyrics to 12 Days of Christmas TV theme songs [Points on graph from top to bottom on the right side of the Y-axis:] That cat bites are really serious and if bitten you should wash the bite and call a doctor immediately Red flags for an abusive relationship Signs for a stroke Cough into your elbow, not your hand That you have to empty the dryer lint trap Stop, drop, and roll That you have to pay taxes

Reindeer

Reindeer

https://www.xkcd.com/1776

https://www.explainxkcd.com/wiki/index.php/1776:_Reindeer

[Black Hat and a boy, with a lot of dark hair, are standing to the right of an empty sleigh pulled by a reindeer with eight spider-like legs. Black Hat has raised one arm towards the reindeer and the boy has his arms out to either side.] Black Hat: In earlier Norse myths, the eight reindeer were actually one steed with eight legs . Black Hat: So I think this is more authentic. Boy: Aaaaaa!

In this Christmas comic Black Hat is at it again, freaking out a young child, by replacing the eight reindeer of Santa's sleigh with a single spider-legged reindeer, thus with eight legs. He considers this "more authentic" because Santa Claus is based on Odin (among many other things) , the chief god of Norse mythology. On the pagan holiday of Yule , Odin was said to ride his eight-legged horse, Sleipnir , across the land. Children would leave one of their boots out and fill it with hay for Sleipnir to eat, then Odin would refill the boot with gifts. This predates the Christmas tradition of hanging stockings by the chimney. The traditional interpretation of the horse with eight legs is a normal equine body, with a pair of identical legs where each leg of a normal horse is. As such, Sleipnir looks majestic and not entirely unnatural. Black Hat's interpretation is to use the body plan of a spider. The result of this is to make a chimaera that is both creepy and terrifying, [ citation needed ] particularly to those with arachnophobia (the quite common fear of spiders). [ citation needed ] The title text is a parody of two lines from the poem " Twas the Night Before Christmas ", "And then in a twinkling, I heard on the roof / The prancing and pawing of each little hoof." The lines are changed to what they could have been if Santa had a spider-legged reindeer - the sound of "eight tarsal claws", referring to the small pair (or triplet) of claws at the end of each of a spider's eight legs. These claws allow them to hold onto objects, including their own web. However, as such an eight-legged spider would have 16 or 24 claws, the text is slightly incorrect. [Black Hat and a boy, with a lot of dark hair, are standing to the right of an empty sleigh pulled by a reindeer with eight spider-like legs. Black Hat has raised one arm towards the reindeer and the boy has his arms out to either side.] Black Hat: In earlier Norse myths, the eight reindeer were actually one steed with eight legs . Black Hat: So I think this is more authentic. Boy: Aaaaaa!

Dear Diary

Dear Diary

https://www.xkcd.com/1777

https://www.explainxkcd.com/wiki/index.php/1777:_Dear_Diary

[Black Hat is seated at a table, writing with a pencil in a diary.] Writing: Dear Diary, Writing: Hello. I am the Crown Prince of Nigeria. I have recently come into a large fortune, but...

Black Hat is writing in a diary (probably his, but possibly not; see below). His entry starts with the common idiom "Dear diary". In a regular diary entry, this opening is used to give the impression of writing to a trusted friend, the diary being anthropomorphized to take that friend's role. However, where other people would write about their day or put their feelings into words, Black Hat's diary entry consists of a standard phishing scam attempting to request some private information in exchange for a large cash amount which does not exist. In this case, the scam is the infamous Nigerian Royalty scam , where the 'royalty' needs bank details to give money, when it will in fact be taken. Black Hat apparently is so used to tricking people that even his own anthropomorphized diary is not safe from his pranks. Alternatively, the entry is intended for anyone who looks at his diary without his permission. It's also possible he has obtained someone else's diary and is somehow trying to scam the diary's owner, although it's not clear how that might work. Or, since it is a rather obvious scam, he may simply being trying to scare the diary's owner, perhaps the same child as he traumatized in the previous comic with a reindeer mutated to look like a spider. This comic creates a stark contrast by putting together elements that seem similar, but do not belong together, for comedic effect. It is possible that the diary is actually the journal from the Journal series, and that ever since being outdone by Danish , he no longer uses it for recording all the things he would say if he were nice. The title text is similar to 1675: Message in a Bottle , which also uses the word "unsubscribe" in an unusual way. The title text also mimics a standard way to get off some mailing lists, so perhaps it's Randall 's diary that Black Hat is molesting, and therefore the title-text is Randall expressing a desire to be disassociated from it. [Black Hat is seated at a table, writing with a pencil in a diary.] Writing: Dear Diary, Writing: Hello. I am the Crown Prince of Nigeria. I have recently come into a large fortune, but...

Interest Timescales

Interest Timescales

https://www.xkcd.com/1778

https://www.explainxkcd.com/wiki/index.php/1778:_Interest_Timescales

[At the bottom of this chart there is a long double arrow pointing at two words:] Fast Slow [Above the line there are four drawings going from left to right:] [Cueball watches a fireworks display to the left of him, two firework rockets are going up and another one is exploding even higher.] Cueball: Ooooh! [A tine Cueball is watching a space rockets launch to the left of him while he is holding his arms in the air. The main rocket rises on a hughe plume of smoke.] Cueball: Wow! [Cueball climbs a tree, holding on to the left of the two main branches going out from the trunk beneath the treetop.] Cueball: Zoom! [A person, presumably Cueball, is standing at the tip of the highest mountain in a mountain range. The largest mountain in the background has three peaks, with Cueball on top of the tallest central peak. Four other much smaller (or distant) peaks are shown behind the big mountain, two on either side. All five mountains have a line beneath the tip that most likely indicate snow. On the big mountain the two tallest peaks are above this line, but not the third.] Cueball: Wheeeee! [Caption below the panel:] Most of my interests fall under "things rising up from the ground, hanging in the air, and then drifting away on the breeze," just on very different timescales.

Randall 's sharing a bit about himself and the things that interest him, in one of his strange but still funny graphs. The caption reads: "Most of my interests fall under 'things rising up from the ground, hanging in the air, and then drifting away on the breeze,' just on very different timescales." The four examples fit this as follows: In the case of a fireworks display, the fireworks fire up into the air, explode, and then the glowing embers drift away on the breeze in the course of a few seconds. This comic was the last released before this years New Year comic 1779: 2017 , so this may explain the thoughts of fireworks. In the case of a rocket launch, the rocket launches from the ground into space, leaving a large plume of smoke that slowly dissipates over many minutes. The rocket remains in space for a time, and then later it re-enters the atmosphere and reaches the ground—in the case of a typical parachute-descent system, it literally drifts through the air. A typical timespan for such an event is several days or weeks. In the case of a tree, it grows from the ground upwards, remains there until autumn comes, then drops its leaves, which drift on the breeze. This process takes months. Entire trees like the one shown typically last several decades or even centuries before they die - if not felled by humans, most are eventually toppled by the wind as well. The breeze needed for that can be measured on the Beaufort scale , likely above 5. Finally, in the case of a mountain, a mountain rises slowly from the ground due to movement of tectonic plates which result in mountains either via volcanic activity or by simply pressing the ground up through the process of subduction (see 1388: Subduction License ). The mountains are then very slowly broken down by natural erosion forces, and the stone particles disperse on the wind. These events are much slower than the others, typically taking tens of millions of years to completely erode away a mountain. Additionally, some humor stems from the fact that Cueball acts like the mountain is a roller coaster , even though a mountain may take thousands or millions of years to noticeably change. The title text refers to the dramatic event in which a mountain suddenly explodes due to a violent volcanic eruption. Such events are rare and potentially deadly to living things. Calling it "extra interesting" is an understatement. [At the bottom of this chart there is a long double arrow pointing at two words:] Fast Slow [Above the line there are four drawings going from left to right:] [Cueball watches a fireworks display to the left of him, two firework rockets are going up and another one is exploding even higher.] Cueball: Ooooh! [A tine Cueball is watching a space rockets launch to the left of him while he is holding his arms in the air. The main rocket rises on a hughe plume of smoke.] Cueball: Wow! [Cueball climbs a tree, holding on to the left of the two main branches going out from the trunk beneath the treetop.] Cueball: Zoom! [A person, presumably Cueball, is standing at the tip of the highest mountain in a mountain range. The largest mountain in the background has three peaks, with Cueball on top of the tallest central peak. Four other much smaller (or distant) peaks are shown behind the big mountain, two on either side. All five mountains have a line beneath the tip that most likely indicate snow. On the big mountain the two tallest peaks are above this line, but not the third.] Cueball: Wheeeee! [Caption below the panel:] Most of my interests fall under "things rising up from the ground, hanging in the air, and then drifting away on the breeze," just on very different timescales.

2017

2017

https://www.xkcd.com/1779

https://www.explainxkcd.com/wiki/index.php/1779:_2017

[Cueball and Megan walking outdoors] Cueball: Can't wait for this stupid year to be over. [The two approach a fallen tree] Megan: I can. This year made the future scarier. So much of why 2016 was bad was because of the things it sent us into 2017 without. [Megan has hopped up onto the tree trunk and begins to walk along it] Cueball: You gotta have hope, though. Megan: You say that, but you also said all this awful stuff couldn't happen, and it did. You're as clueless as the rest of us. [Cueball also walks along the tree trunk as Megan stops and turns to look at him] Cueball: Well, if we're wrong about which bad things can happen, it's got to make us at least a little less sure about which good things can't. [Closeup of Megan hopping down from the tree] Megan: I guess. [A distant shot of Megan and Cueball walking along again] Cueball: Plus, 2017 has a cool eclipse in it. Megan: Ooh, yeah! Cueball: And it's prime. Prime years have always been good for me. Megan: Sure, I'll take it.

In this New Year comic , Cueball and Megan share some of their (or Randall's ) thoughts about the ending 2016 and the new year 2017 (hence the title). 2016 was a year which many people eagerly awaited the end of because of its increased turmoil (terrorist attacks, controversial political events in numerous countries including the election of Donald Trump for president in the United States and the United Kingdom voting for Brexit ) as well as the deaths of an unusually large number of well-known and beloved celebrities (several of these died in the first few days after Christmas). Instead of simply condemning 2016 as a terrible year and expecting 2017 to be significantly better, Megan observes that much of what made 2016 bad is the effect that it will have upon future years rather than the actual events themselves (for instance, a divisive U.S. presidential election has caused significant controversy in 2016, but President Donald Trump actually took office and began to affect the world as President in 2017). Megan specifically states that 2016 was bad was because of the things it sent us into 2017 without. As it is known that Randall is a Hillary Clinton supporter (as shown in the 1756: I'm With Her comic), an additional reading of that line could be that we are headed into 2017 "without" a Hillary Clinton presidency. It can also refer to the many dead celebrities passing in 2016, (at least three famous musicians/actors so recent that they died after Christmas Eve), as we would be without all of them in 2017. Cueball claims that they should still have hope for the future, but Megan states that people had claimed that many of the bad things that did happen in 2016, could not happen (for instance Trump and Brexit). And as these things did happen, she foresees even worse events occurring in 2017, that we did not even think would be possible. However, Randall also offers a glimpse of hope in the last few panels when Cueball observes that, just as all of the bad things in 2016 were unexpected, good things in 2017 that are unexpected could also happen, which should make us less sure what good may come of 2017. As such, he argues that we should hold on to our hope even though things seem difficult right now. As the conversation unfolds, Megan and Cueball encounter an uprooted tree and cross it like a balance beam. This is a visual metaphor; the dead tree represents the end of the old year, while the crossing represents the transition into the new year. This is similar to the magical toboggan from Calvin and Hobbes that serves as a metaphor for their conversations, mentioned in 529: Sledding Discussion and 409: Electric Skateboard (Double Comic) . In the last panel Cueball mentioned that 2017 will also have a cool eclipse , going through the central parts of North America. This may also serve as a reminder that the Earth continues to spin on despite all of the human turmoil going on on its surface. This is literally true, as the eclipse Randall is excited about is caused by the orbits of three celestial bodies lining up just right (the Sun, the Earth, and the Moon). Cueball then also notes that 2017 is a prime number and states that prime-numbered years (prime years) have always been good to him. He thus illustrates the positive attitude that people can choose to take in order to see all that which is good and to spread a little bit more cheerfulness, and Megan is ready to take this positive view, although she may not totally buy in to it. This could also be a pun referencing the saying "being in his prime years". The title text is a reference to Nate Silver who is well-known (in the United States) as an election polling analyst on FiveThirtyEight . His model allowed for a higher chance that Donald Trump would win the presidency compared to other similar models — though the fact that he still favored a Clinton win may be contributing to getting humor from the idea that he may be "wrong" again, and the Moon could possibly vanish in 2017, making the year definitely worse than 2016. (Earth and Moon are so close in the space order of things, that any event affecting Moon orbit seriously will almost certainly end our civilization too.) This is accentuated by the qualifier "almost definitely", which is of humorously low confidence for presenting a fact as certain as the Moon not somehow disappearing within the next year. In the background of the first few panels of this comic, we see a fallen tree, but a sapling growing in its place. This may be a subtle message by Randall that there is still hope, and that things will be alright in the end. Randall previously mentioned his excitement for the 2017 eclipse exactly three years earlier in 1302: Year in Review , where Megan complains about not having seen an aurora during 2013, and she really hopes they don't cancel the 2017 eclipse. So this comic is the second time Randall has expressed concern that he will miss the eclipse. Leading up to and after the eclipse Randall released six more comics on the subject: 1868: Eclipse Flights , 1876: Eclipse Searches , 1877: Eclipse Science , 1878: Earth Orbital Diagram , 1879: Eclipse Birds , and 1880: Eclipse Review . There have been three previous New Year's comics with only the year used as the title: 998: 2012 in 2012, 1311: 2014 in 2014 and 1624: 2016 in 2016. This is the first odd-numbered year (and thus of course the first prime year) using only the new year as the title. [Cueball and Megan walking outdoors] Cueball: Can't wait for this stupid year to be over. [The two approach a fallen tree] Megan: I can. This year made the future scarier. So much of why 2016 was bad was because of the things it sent us into 2017 without. [Megan has hopped up onto the tree trunk and begins to walk along it] Cueball: You gotta have hope, though. Megan: You say that, but you also said all this awful stuff couldn't happen, and it did. You're as clueless as the rest of us. [Cueball also walks along the tree trunk as Megan stops and turns to look at him] Cueball: Well, if we're wrong about which bad things can happen, it's got to make us at least a little less sure about which good things can't. [Closeup of Megan hopping down from the tree] Megan: I guess. [A distant shot of Megan and Cueball walking along again] Cueball: Plus, 2017 has a cool eclipse in it. Megan: Ooh, yeah! Cueball: And it's prime. Prime years have always been good for me. Megan: Sure, I'll take it.

Appliance Repair

Appliance Repair

https://www.xkcd.com/1780

https://www.explainxkcd.com/wiki/index.php/1780:_Appliance_Repair

[Cueball faces Megan and White Hat as he stands in the middle of a mess of a dissasembled machine, holding a screwdriver.] Cueball: After disassembling and inspecting the humidifier, I've determined that the main problem with it is that someone took it apart.

Cueball is either trying to repair his appliances himself or possibly running an appliance repair service. Although, he isn't doing much in the repairs aspect, as he is diagnosing problems with the appliances that he himself caused. Megan and White Hat (supposedly) call him over to have him fix a humidifier that isn't working. As most repairmen/handymen do, he takes apart the machine to find the root of the problem. However, after this he states the reason it isn't working is because someone took it apart. In this case it was Cueball himself. This would not be very helpful for repairing the appliance. [ citation needed ] In the title text it is mentioned that Cueball is holding up a three-phase motor that he has taken from the humidifier. Normally when a person repairing an appliance shows you a part, they are showing you the part of the machine that was broken. In this comic however, Cueball is just showing off a (presumably) random part of the machine and stating that the problem is that the machine it came from is broken – something that was already known and unlikely to help find the root cause of the problem. In addition, it is unlikely that the part being held ever would have worked, because three-phase motors won't work on residential power in North America. Residential humidifiers use single-phase voltage , while three-phase equipment uses three-phase voltage . This might also be a reference to self reference which is referenced in xkcd sometimes. [Cueball faces Megan and White Hat as he stands in the middle of a mess of a dissasembled machine, holding a screwdriver.] Cueball: After disassembling and inspecting the humidifier, I've determined that the main problem with it is that someone took it apart.

Artifacts

Artifacts

https://www.xkcd.com/1781

https://www.explainxkcd.com/wiki/index.php/1781:_Artifacts

[Cueball is standing on a podium pointing at his presentation which includes a large line graph in the center part. There is plenty of text on the presentation, but none of it is readable. The central part of the line is raised high above the left and right part. The point where the line drops towards right is highlighted with a circle, with a double arrow above it pointing to a caption. There is also text next to the circle to the right. Above the graph there are three smaller panels with drawings. There is one caption above these, and also one above the large graph. Below the graph there are two smaller panels with curves, each panel has it's own caption. Cueball addresses an unseen audience, and one from the audience interrupts him.] Cueball: The data clearly proves that- Offscreen voice: Are you Indiana Jones? Offscreen voice: Because you've got a lot of artifacts there, and I'm pretty sure you didn't handle them right.

The comic shows Cueball presenting data that was probably gathered in research. It's not clear what type of data it is, but one spike has been highlighted on the graph, despite this spike being apparently no larger than the noise in the data (and is much smaller than the central peak). Cueball seems to have made some kind of mistake in either the statistics or the measurement of the undefined subject of his research, thus his data results in many outliers. The word artifact is a wordplay with two meanings. It is either an archaeological artifact (such as the Holy Grail as in Indiana Jones and the Last Crusade ) or a fault in your experiment, where you (usually accidentally) influence the measurement with your equipment or unanticipated environmental factors. These are called error artifacts . Indiana Jones is (often humorously) cited as being a bad archaeologist . He often destroys the area he is looking for artifacts in, despite the context in which they were found being as or more important, archaeologically, than the artifacts themselves. He does not appear to make any records, carries the artifacts around without any thought for their ancient and fragile nature, and most often ends up losing the artifacts altogether. An example of an error artifact is the measurement of the force between two charged metal spheres ( Coulomb force ), where the potential of unearthed nearby objects influences the measurement, thus causing an artifact. Artifacts have been mentioned before in xkcd, as in 1453: fMRI , where getting into the MRI machine induced unintended effects, such as thoughts of claustrophobia. The title text refers to the entire data set being "outliers." In statistics, an outlier is an observation point that is distant from other observations. One way to have a data set composed entirely of outliers would be a data set with N points, in a 1/2 N-dimensional space, where each point is zero for every dimension except one, unique to itself. The 1/2 is because there would also be a -1 point. [1] All these points are equidistant from each other. We could also infer that the accusation is a jab at the fact that the data points are all over the place; a good example of such chaotic data can be see in 1725: Linear Regression . [Cueball is standing on a podium pointing at his presentation which includes a large line graph in the center part. There is plenty of text on the presentation, but none of it is readable. The central part of the line is raised high above the left and right part. The point where the line drops towards right is highlighted with a circle, with a double arrow above it pointing to a caption. There is also text next to the circle to the right. Above the graph there are three smaller panels with drawings. There is one caption above these, and also one above the large graph. Below the graph there are two smaller panels with curves, each panel has it's own caption. Cueball addresses an unseen audience, and one from the audience interrupts him.] Cueball: The data clearly proves that- Offscreen voice: Are you Indiana Jones? Offscreen voice: Because you've got a lot of artifacts there, and I'm pretty sure you didn't handle them right.

Team Chat

Team Chat

https://www.xkcd.com/1782

https://www.explainxkcd.com/wiki/index.php/1782:_Team_Chat

[Hairbun holding up her palm toward Cueball. A frame over the top border of the panel has a caption:] 2004 Hairbun: Our team stays in touch over IRC. [Megan is looking at Ponytail who is holding up her palm toward her. A frame over the top border of the panel has a caption:] 2010 Ponytail: Our team mainly uses Skype, but some of us prefer to stick to IRC. [Cueball is talking with Megan in a frameless panel. A frame at the top of the panel has a caption:] 2017 Cueball: We've got almost everyone on Slack, Cueball: But three people refuse to quit IRC and connect via Gateway. [A black panel with white text and drawings. The main body of text is above a the singularity, a starburst around a circle with two more broken lined circles around the starburst. To the right another Cueball-like guy floats in space with his laptop computer, typing on the keyboard. A frame, that is white inside, is over the top border of the panel has a caption: ] 2051 Narration: All consciousnesses have merged with the Galactic Singularity, Narration: Except for one guy who insists on joining through his IRC client. One Guy: I just have it set up the way I want, okay?! Galactic Singularity: *Sigh*

Randall provides us with a – presumably anecdotal – montage of the Internet's changing attitude towards different instant messaging protocols, framed within the context of a team trying to remain in communication while tolerating each others' different tastes. Although one-on-one "talk" programs date back to 1960s mainframes, Internet Relay Chat (IRC) was one of the first real-time group communication protocols, invented in 1988. While it remains the format on which most later apps were based, the convenience and accessibility of other protocols such as AIM and Skype gradually exceeded IRC in popularity. Many users took to the new environments, but others preferred the old and familiar, hence schisms between groups began to grow. Skype and Slack are both proprietary centralized communication protocols (usually used through their official clients). Skype focuses mainly on voice communication, be it for personal or business use, and own installable client, while Slack relies almost entirely on text communication, focuses on work communication and works completely well in its own web client, even though official desktop and mobile clients are available as well. Slack also features a huge customizability (bots, plugins) possibly inspired by IRC, and its users need to create communication teams, working inside subdomains at *.slack.com. It is possible to connect to Slack via IRC as well, using a third-party gateway. (Originally, Slack had a gateway feature , if allowed by the team's admin, but that was turned off in mid 2018, after the publication of this comic.) Randall here seems to be commenting on the persistence of IRC; while generally considered to be ancient software in comparison to newer and still-competing protocols, its endless customizability has led some people to support it above all others. Extrapolating for the sake of humor, the joke here lies in a particularly uncommon but memorable type of Internet denizen: even in a far-off distant future where the world's technology has led to a superlative messaging network encompassing all people in some supposed, incredible bliss, there is always — in Randall's vision — going to be That IRC Guy. This might also be a reference to the scenarios in science fiction stories such as Isaac Asimov's concept of Galaxia in the Foundation novels, or the concept of a merged human-computer intelligence as in "The Last Question" [1] , the concept of which is most notably highlighted by this line: [...] One by one Man fused with AC, each physical body losing its mental identity in a manner that was somehow not a loss but a gain. [...] In the title text, both screen and tmux are unix programs that help you multitask while working in terminal, and irssi and weechat are both communication clients supporting mainly IRC, capable of working in a terminal environment. Tmux is a newer and apparently more user-friendly project, complete with handy menus and titles, while screen is something of an industry standard, but relatively difficult to use – you need to know what you are doing or read help before using it, otherwise you get lost and frustrated. [2] The same it is with the newer, more feature-packed and user-friendly weechat vs industry-standard, harder-to-use irssi. [3] Basically, that one guy is a hardcore UNIX geek who doesn't use any graphical user interface, and in 2051 he still chooses to use terminal-emulation-based tools. Timing of this strip follows the release of irssi version 1.0.0 . Randall touched on similar themes earlier in 927: Standards and later in 2365: Messaging Systems . [Hairbun holding up her palm toward Cueball. A frame over the top border of the panel has a caption:] 2004 Hairbun: Our team stays in touch over IRC. [Megan is looking at Ponytail who is holding up her palm toward her. A frame over the top border of the panel has a caption:] 2010 Ponytail: Our team mainly uses Skype, but some of us prefer to stick to IRC. [Cueball is talking with Megan in a frameless panel. A frame at the top of the panel has a caption:] 2017 Cueball: We've got almost everyone on Slack, Cueball: But three people refuse to quit IRC and connect via Gateway. [A black panel with white text and drawings. The main body of text is above a the singularity, a starburst around a circle with two more broken lined circles around the starburst. To the right another Cueball-like guy floats in space with his laptop computer, typing on the keyboard. A frame, that is white inside, is over the top border of the panel has a caption: ] 2051 Narration: All consciousnesses have merged with the Galactic Singularity, Narration: Except for one guy who insists on joining through his IRC client. One Guy: I just have it set up the way I want, okay?! Galactic Singularity: *Sigh*

Emails

Emails

https://www.xkcd.com/1783

https://www.explainxkcd.com/wiki/index.php/1783:_Emails

[Megan and Cueball are walking along.] Megan: Did you have any New Year's Resolutions? Cueball: Gonna finally finish dealing with those emails from 2008. [Caption below the panel:] As my email backlog approaches 10 years, I'm starting to have doubts about my approach.

In this rather late New Year comic (January 9th), Megan asks Cueball if he has any New Year's resolutions . New Year's is, to many people, a time for thinking about the year and coming up with resolutions to improve themselves. These kind of resolutions hardly ever work . Cueball replies that he has one resolution. It's to finish reading and replying to his backlog of emails from 2008, 9 years prior to this comic. He obviously does not read his email when they arrive in his inbox, and he now vows to at least get those e-mails from 9 years ago read. As he further states in the caption below, he now (finally) begins to doubt his method for replying to e-mails, since his backlog now approaches 10 years. Some would probably say he should have found this out when his backlog approached 10 days, or at least when it reached a month. A common technique for some more productive or efficient users of email is to batch reply to email instead of replying to each one individually as they come. The principle is that setting aside specific times to reply instead of always being "on call" gives the messages the attention they deserve while avoiding the urge to constantly check your email when you should be doing important work. Such a technique could be to check and answer all your emails once a day, or once a week, for instance and allocating a specific amount of time like one hour every day to do so. It is unlikely that somebody would wait years to start the task of checking emails, so obviously the time reserved per unit of time is way too short, if even existing. This would create a backlog of emails, that could soon be so large it would take years to catch up to the e-mail you just got right now. Another technique for efficient people is not to answer certain e-mails; if a subject really is important, the sender will send a reminder a few days later. (If he does not, the sender can be presumed to have solved the problem himself, saving lots of time on the receiver's side. Of course then you have to check your e-mails to realize if someone has sent a reminder.) Cueball has possibly used this technique on a friend's request, but became remorseful after nine years. The title text is a reply to an email in which Rob wished to see the movie WALL-E , a film that came out in 2008, with Cueball during its opening weekend. However, the opening weekend is now far in the past, and yet Cueball doesn't realize it and trails off with "are you still doing that, or...?" Mentioning the release of a popular movie and then making it clear that it will soon be ten years ago that the movie came out, feels a lot like a hidden comic to make one feel old , but it may be stretching it to include this directly in that category. But it is a technique often used by Randall , quite clearly in most of that category, for instance 891: Movie Ages . A real (and useful [ citation needed ] ) New Year's resolution would involve trying to answer his emails as they arrive (instead of spending any more time on years old emails), which would have avoided the mess he's currently in, and will stop it from getting worse in the future. In this comic Cueball may represent Randall . He receives so many e-mail due to the xkcd comic that he may have a hard time going through them all. Then there is his what if? email, and possibly many more. Hopefully he has a separate e-mail for friends that wish to send him a request for going to the opening of new recent movie. On the about page on xkcd he does write the following for one of the e-mails he cites as contact: press @ xkcd.com -- Press questions, etc (may take a long time to get to me). [Megan and Cueball are walking along.] Megan: Did you have any New Year's Resolutions? Cueball: Gonna finally finish dealing with those emails from 2008. [Caption below the panel:] As my email backlog approaches 10 years, I'm starting to have doubts about my approach.

Bad Map Projection Liquid Resize

Bad Map Projection: Liquid Resize

https://www.xkcd.com/1784

https://www.explainxkcd.com/wiki/index.php/1784:_Bad_Map_Projection:_Liquid_Resize

[Caption at the top of the panel:] Bad map projection #107: The Liquid Resize A political map compressed using Photoshop's content-aware resizing algorithm to cut down on unused blank space [Below the caption there is a map of the world divided and colored by political boundaries, with outlines around each continent in black and around each country in dark gray. Antarctica is colored in light gray, bodies of water in white, and countries in pale shades of red, orange, yellow, green, blue, and purple. The map is heavily distorted, with Africa in the center and the other continents curving around it, approximating the bounds of a square with rounded corners. The oceans have been removed but also huge countries like the US, Australia, Brazil, Russia and especially India and Argentina have been heavily distorted while areas in the center with many smaller countries like Africa and Europe is almost unchanged.]

This is the first comic in the series of Bad Map Projections presenting Bad map projection #107: The Liquid Resize. This turned into a series when 1799: Bad Map Projection: Time Zones (#79), was released just a bit more than a month after this one. There is no perfect way to draw a map of the world on a flat piece of paper. Each one will introduce a different type of distortion, and the best projection for a given situation is sometimes disputed. Randall previously explored 12 different projections in 977: Map Projections , and expressed his disdain for some types he sees as less efficient but whose users feel superior. None of them are truly perfect as any 2D map projection will always distort in a way the spherical reality, and a map projection that is useful for one aspect (like navigation, geographical shapes and masses visualization, etc.) will not be so for all the others. Local maps of smaller areas can be quite accurate, but the idea of both these map projection comics is to map the entire globe on a flat surface. This comic suggests that there are many other projections than the 12 from the previous map projection comic, and Randall seems to have an entire list, of which at least 358 are "Bad Map Projections." The one presented here is #107 and is it called the "Liquid Resize." It is unclear if he includes the previous 12 in this list. Quite possibly he does, since all 2D projections of the surface of a 3D sphere will be bad in certain respects. (The next comic's projections Time Zones based on these, has #79 and could be concluded as being less bad than this one, which also seems realistic as this map looks more like a normal map projection, although it also has huge flaws). The Liquid Resize map projection, however, is not only useless for most map applications -- as the size, shape, and position of most countries are quite distorted -- but its creation includes two steps which are outright counterproductive. If the list is sorted from best to worst it may be hard to find a worse projection method than this, so finding 106 projections better than this one seems realistic! First, this method needs a planar map projection as its starting point, thus compounding the problems right off the bat. Planar projections are relatively accurate near the center but heavily distorted toward the edges. A famous example of a planar projection is the logo of the United Nations . Planar projections are basically only useful for 3D graphics rendering, if the user needs a quick, inexpensive way to store map textures that will later be attached to a sphere. Second, the map uses Photoshop's content aware resizing tool , a very questionable choice. [ citation needed ] (Using a Photoshop tool for a task it is not intended for was also used in 1685: Patch where a GNU patch tool was replaced with Adobe Photoshop's patch tool to compile code.) The content aware resizing tool resizes images by identifying what it thinks are important details and preserving these, while shrinking or stretching less detailed areas. For example, when used on a face , the algorithm detects that the eyes and mouth are important details and tries to keep these in place, while stretching the skin around it. When applied to a map, this means that areas with lots of countries - and therefore lots of detail - such as Europe, West Africa, the Eastern Mediterranean and Central America/the Caribbean are relatively unchanged, while big countries like India, China and the US are very warped. The choices that the resizing tool makes are also dependent on the exact visual features of the original map, such as the choice of not having any topography or infrastructure drawn on, or not including a latitude/longitude grid, so what areas are deemed as unimportant is even more arbitrary than it would be on, say, a photographic picture of the Earth. Bad content aware scaling is already a meme. This projection does do a good job, however, of making almost every country clearly visible and indicating which countries are neighbors. South America fits into Africa almost as it did in the era of the super-continent Pangaea . Tissot's indicatrices are equally sized small circles overlaid on a globe to show the distortion of a particular map projection; if the map distortion distorts the shapes or areas of countries, it will do the same to the circles. The title text suggests that the shapes of Tissot's indicatrices would be pretty well preserved by the Liquid Resize transformation, 'as long as you draw them in before running the resize'. This is a joke. "Drawing them in before running the resize" means that a different projection would be generated (probably preserving the indicatrices themselves), making the use of the indicatrices meaningless, sort of like cheating. In fact by drawing them small enough there will be no resizing at all. [Caption at the top of the panel:] Bad map projection #107: The Liquid Resize A political map compressed using Photoshop's content-aware resizing algorithm to cut down on unused blank space [Below the caption there is a map of the world divided and colored by political boundaries, with outlines around each continent in black and around each country in dark gray. Antarctica is colored in light gray, bodies of water in white, and countries in pale shades of red, orange, yellow, green, blue, and purple. The map is heavily distorted, with Africa in the center and the other continents curving around it, approximating the bounds of a square with rounded corners. The oceans have been removed but also huge countries like the US, Australia, Brazil, Russia and especially India and Argentina have been heavily distorted while areas in the center with many smaller countries like Africa and Europe is almost unchanged.]

Wifi

Wifi

https://www.xkcd.com/1785

https://www.explainxkcd.com/wiki/index.php/1785:_Wifi

[A line graph with a curve that starts just right of the Y-axis above the middle of the axis. Then it increases slightly and stays almost stable on a long flat plateau before it falls off fast towards the right. Each axis ends in an arrow and has a label to the left of the Y-axis and below the x-axis. Over the curve there are three labels, pointing with one arrow to the two rising and falling parts, and three arrows to the center label above the plateau.] Y-axis: Probability houseguest will be able to connect to WiFi X-axis: Houseguest tech-savviness Left label: Can't find wifi settings Center label: Works fine Right label: Something involving the word "firmware"

This comic shows the supposed probability that a guest will be able to connect to the owner's Wi-Fi in graph form. Connecting to a new Wi-Fi network is a fairly simple operation that most people can perform, typically only requiring selecting the correct network name on a settings screen, then entering a password. The graph starts with tech-illiterate people who don't even know how to control their Wi-Fi connection ("can't find wifi settings"). This group has slightly lower than normal probability of connecting successfully, since they would not know what to do if left alone. However, they still have a reasonable chance to connect as long as someone is available to help them. Once the initial setup is done, they can continue using the connection without any technical knowledge or intervention. The average case in the middle of the graph represents typical users who simply wish to connect and gain Internet access ("works fine"). This group of users have enough knowledge to be able to connect and are then satisfied with the connection just working. Since networking devices use a standard protocol to communicate behind the scenes, users typically will not experience any issues. Finally, the large drop in the graph on the right-hand side is explained by "something involving the word 'firmware'". Firmware is programming which operates a device at the lowest level, typically stored in a ROM or an EEPROM/flash. Both Wi-Fi routers and guest's devices (smartphones, tablets, computers) have firmware. Modifying the firmware can have certain benefits, for example to gain features that aren't included in the base product. Also, especially for newly adopted wireless standards (such as, most recently, IEEE 802.11ac ), incompatible interpretations of the standard may prevent devices from different manufacturers from communicating reliably or at full speed, requiring firmware changes to patch the issues. However, working with firmware requires a great deal of technical knowledge, and can be quite risky for people without experience. Not all custom firmware will interoperate correctly with all devices. Technical issues with custom firmware can also be harder to fix due to lack of support from the device manufacturer. In the worst case, installing the wrong firmware, or any errors or glitches in the process, can even leave devices bricked . It's likely that the sharp dropoff in the graph is caused by inexperienced users who know "just enough" to want to modify their firmware, but don't know how to deal with the multitude of issues that can arise. Particularly for users whose connection was already working fine but nevertheless want to experiment with new firmware, their changes often end up worsening their chances of connecting. The title text indicates that the curve recovers once users are more experienced, and can consistently install firmware correctly to get a working connection. In such case, the users are able to enjoy better connections through their firmware changes while avoiding their pitfalls. These experienced users are often able to diagnose and fix connection issues through the appropriate use of firmware, making their chances of connecting even better than the average user. Randall has previously used the title text to add extra info that would not fit in the main graph. This has happened in 388: Fuck Grapefruit , 1242: Scary Names , 2466: In Your Classroom and 1501: Mysteries . The first three have extra data points mentioned there because they are far off the chart, whereas the last has a point whose description would be too long to fit on the chart. All these other graphs are scatter plots, as opposed to this comic being a line-graph. Computer issues have previously appeared in several xkcd comics, notably 456: Cautionary , where WiFi problems specifically are mentioned in the title text. The apparent paradox of people knowing more about a subject also having more problems with it is also explored in 1760: TV Problems . [A line graph with a curve that starts just right of the Y-axis above the middle of the axis. Then it increases slightly and stays almost stable on a long flat plateau before it falls off fast towards the right. Each axis ends in an arrow and has a label to the left of the Y-axis and below the x-axis. Over the curve there are three labels, pointing with one arrow to the two rising and falling parts, and three arrows to the center label above the plateau.] Y-axis: Probability houseguest will be able to connect to WiFi X-axis: Houseguest tech-savviness Left label: Can't find wifi settings Center label: Works fine Right label: Something involving the word "firmware"

Trash

Trash

https://www.xkcd.com/1786

https://www.explainxkcd.com/wiki/index.php/1786:_Trash

[Cueball looking at garbage chute attached to wardrobe. Black Hat answers him from off panel.] Cueball: What's this thing on your wardrobe? Black Hat (off-panel): Garbage chute. [In a frame-less panel Cueball has turned away from the wardrobe (now off-panel) and he walks towards Black Hat.] Cueball: Into a wardrobe? Black hat: There's some sort of portal to a magical land in there. Half the furniture I get has them-it's kinda a pain. [Cueball stops walking closer to Black Hat.] Cueball: You dump your trash in Narnia ? Black Hat: Yeah, it's a real time-saver. Black Hat: There's a huge cat in there, but I have a spray bottle I use when he tries to come up through the chute.

Black Hat is, once again, thoroughly confusing Cueball (another example of this is 908: The Cloud ). This time, when inquired about a chute protruding from his wardrobe, Black Hat explains that it is a garbage chute into another dimension. Apparently these kinds of portals appear on about half of all the furniture that Black Hat buys, and he is somewhat annoyed about it. (This sounds more like something Beret Guy would encounter, although he would have reacted very differently than Black Hat.) It would be interesting to know whether all the portals lead into the same alternative world/dimension, but it seems Black Hat is not interested in visiting these worlds, instead just being annoyed about his broken furniture. (Given Black Hat's personality, this may well be a practical joke meant to mess with Cueball's head rather than an actual portal to another dimension.) Cueball quickly realizes this is a reference to The Lion, the Witch and the Wardrobe , the first published book in The Chronicles of Narnia by C. S. Lewis . In the books, the child characters use different portals to get into the alternative dimension/world of Narnia . The children first find a portal inside an old wardrobe, and use it at least three times to travel into Narnia. Black Hat confirms his trash chute indeed leads to Narnia and explains how this is a great time-saver for him, as he can easily get rid of his trash. The Narnia books are for children and Narnia is a magical world, so Cueball is appalled to learn that Black Hat dumps his trash there. A discussion of problems with this comic vs. Narnia chronology is discussed in the trivia section . The "huge cat" he refers to is Aslan , a magical lion in Narnia that represents God. In his lion form he sometimes walks around and watches over Narnia, but not all the time. It is revealed in the last book that he is also the guardian of the other worlds, where he has different names and takes on different appearances, so he is actually a representation of a benevolent God in many forms. Aslan, or any other large cat or inhabitants of such a different world, would probably be really upset that someone is throwing their trash there [ citation needed ] . He would probably try to stop this by any means necessary, including coming up through a trash chute into another dimension. But because lions are a type of cat (feline), apparently Aslan can be repelled with an ordinary spray bottle. The joke is that this is a technique used to tame small house cats; it would be unlikely to work on a lion, especially if the lion was really a deity [ citation needed ] . In the title text, the fact that time passes much faster in Narnia than on Earth is mentioned. (Time does not pass at a constant rate compared to Earth time.) This could also be the case even if the portal in Black Hat's wardrobe accessed a different world than Narnia. So everything that is actually pushed to the other side of the portal would be disposed of very efficiently, as the trash could completely decompose within just a few Earth minutes. This would then explain how Black Hat can keep pushing more stuff into the other world: anything sent through the portal will decompose and vanish before he comes with his next load of trash. The title text mention of Yucca Mountain is a reference to the Yucca Mountain nuclear waste repository , a partially-built nuclear waste repository that has been defunded at the present time. Black Hat wants to contact those that wish to make such a repository and let them dispose of their radioactive waste through his "magical" portal, likely to make a profit for himself. If throwing trash into Narnia is terrible, radioactive waste would be far worse [ citation needed ] . Of course in Earth time radioactive materials would soon decay back to background levels of radiation. This is thus another jab at all the world's environmental problems, as is also done with all the comics about climate change . This comic could be a take on humans dumping waste in the "endless" oceans, more specifically ocean disposal of radioactive waste . This was done in the past but is now banned, as Earth's oceans are not endless [ citation needed ] . The title text copies the idea behind the Saturday Morning Breakfast Cereal comic from October 15 2014 . The button at the bottom of that comic shows a sad Mr. Tumnus , a faun Lucy meets on her first visit to Narnia, rather than an angry Aslan as suggested in this comic. The portal through the wardrobe to Narnia was previously featured in 665: Prudence , 969: Delta-P and 821: Five-Minute Comics: Part 3 . In the latter, the different passage of time was also mentioned. [Cueball looking at garbage chute attached to wardrobe. Black Hat answers him from off panel.] Cueball: What's this thing on your wardrobe? Black Hat (off-panel): Garbage chute. [In a frame-less panel Cueball has turned away from the wardrobe (now off-panel) and he walks towards Black Hat.] Cueball: Into a wardrobe? Black hat: There's some sort of portal to a magical land in there. Half the furniture I get has them-it's kinda a pain. [Cueball stops walking closer to Black Hat.] Cueball: You dump your trash in Narnia ? Black Hat: Yeah, it's a real time-saver. Black Hat: There's a huge cat in there, but I have a spray bottle I use when he tries to come up through the chute.

Voice Commands

Voice Commands

https://www.xkcd.com/1787

https://www.explainxkcd.com/wiki/index.php/1787:_Voice_Commands

[Ponytail is looking at Cueball facing her direction, and he looks down at the smartphone he is holding in his hand.] Ponytail: Can you text it to me? Cueball: Sure! Cueball: Svat ussupd ;dlh a kdbk Ponytail: ...What? Phone: *Beep* [Caption under the panel:] Setting my phone's speech recognition to Dvorak was a pain at first, but it's more efficient in the long run.

In this comic Cueball has shown Ponytail something relevant to her on his smartphone and she asks if he can send it to her. He agrees but then says something completely incomprehensible to Ponytail, but obviously his phone understands and sends the message with a beep. The caption explains that he was speaking as though he was using a QWERTY keyboard layout and writing as it was a Dvorak Simplified Keyboard . In other words, Cueball is saying keys on a Dvorak keyboard and the phone is receiving the spaces on a QWERTY keyboard that each of Cueball's Dvorak letters uses. Cueball can be sure that nobody else will be able to use voice commands on his phone. The sentence Cueball tells his phone translates to "Okay Google send a text" - he says it as if he were typing the sentence on a Dvorak layout with the keyboard set to a QWERTY layout. How such words would be pronounced is a mystery, as the letters in the words are merely substituted with others with no regard to phonetics; without standardized pronunciations, a speech-to-text program would be useless. To add to the confusion, one of the words in Cueball's sentence includes a semi-colon as one of its letters despite the fact that semi-colons are punctuation rather than phonemes, which only complicates the pronunciation further. The title text is a reference to the fact that many users of Dvorak keyboards claim they may be hard to learn, but they are more movement efficient and put less stress on your fingers due to less movement. This makes little sense in the scenario set up by the comic, as speaking gibberish using oddly placed vowels would be equally difficult, if not in fact harder, on the vocal cords. [ citation needed ] [Ponytail is looking at Cueball facing her direction, and he looks down at the smartphone he is holding in his hand.] Ponytail: Can you text it to me? Cueball: Sure! Cueball: Svat ussupd ;dlh a kdbk Ponytail: ...What? Phone: *Beep* [Caption under the panel:] Setting my phone's speech recognition to Dvorak was a pain at first, but it's more efficient in the long run.

Barge

Barge

https://www.xkcd.com/1788

https://www.explainxkcd.com/wiki/index.php/1788:_Barge

[There is one panel in this comic with the main drawing at the bottom. Two smaller drawings are inserted above this drawing to explain the idea.] [The first insert shows a barge with no center and a large piece of paper with the SpaceX logo above the barge.] [The second insert shows the paper stretched over the hole.] [The main drawing at the bottom shows a cross-section of the barge in water, showing there is only water below the paper. Above the paper the large first stage, without the top part with the payload, of a reusable rocket is attempting to land on the paper on the SpaceX logo (not visible in this view). It is still so high above the fake barge that the exhaust fire below the rocket is nowhere near the paper.] [Caption below the panels:] My hobby: Hollowing out the center of a barge, stretching paper over the hole painted with the SpaceX logo, and leaving it floating offshore near launch sites.

This is another one of the " My Hobby " series, where Randall tells about a strange hobby. This one is depicted with three drawings illustrating the core concept, and explained in details in the caption. The launch company SpaceX has developed a reusable rocket system, where the first rocket stage is capable of landing back on either the launch pad or an autonomous spaceport drone ship after launch (See this video displaying both types of landing, from when the sea landing was successful the first time). The landing pads and ships are decorated with a "X" symbol from the SpaceX logo, with the center of the X being the desired landing spot. [ citation needed ] Randall imagines creating a similar-looking barge and placing it near the intended landing site, except his barge's platform would be hollow in the middle with only a sheet of paper supporting the part where the rocket would land. Since the paper is painted to look just like the real landing platform, the goal of this setup is presumably to trick a returning first stage rocket into falling into the sea. This is the same concept as the old trapping pit . If a rocket attempts to land on Randall's barge, it will quickly burn through the paper and fall through the hole. There are several reasons why this setup would not work in real life. First, the rocket actually navigates to the landing site using GPS coordinates shared with the real barge. It does not use cameras to identify its landing site and will not recognize another barge based solely on a painted logo. Also, a wide area around the rocket's flight path would be restricted around the launch window due to safety concerns. Vessels that are not part of the official launch plan would not be allowed in the area. Even if the fake barge manages to enter the area and does not get removed by authorities, at most it will cause the launch to be canceled for the day. This "my hobby" is probably the most destructive one so far, as it would result in the total loss of the first stage containing nine space rocket engines. The costs associated with buying and remodeling a barge would also likely make this the most expensive hobby, even disregarding the costs to others, though it could potentially be reused if it did not get destroyed by the falling rocket. This hobby seems more appropriate for Black Hat , considering that he is a real classhole , and goes to show that Black Hat is as much part of Randall's personality as Cueball . The title text plays on the incredible difficulty of landing a rocket on a barge. Reusing rockets like this is a feat that has only recently become possible, some 60 years after the launch of the first satellite Sputnik 1 . SpaceX, founded by Elon Musk , was the first (and so far only) organization to do so successfully. Blue Origin is also currently testing reusable rockets and achieved landing their first stage before SpaceX, albeit only on land and only with a sub-orbital rocket . Thus Randall imagines an even more implausible idea of turning the scenario upside down and getting a barge to land on one of Elon Musk's rockets. That would be a spectacular feat of engineering, and the challenges it presents as well as its inherent irony appear to satisfy Randall so much that he would make it into one of his life goals. Launching a barge in the first place would be tremendously difficult - they are big, heavy and not very aerodynamic . Maneuvering it through the air precisely enough to come down on top of a rocket would be difficult as well. The barge (and probably the rocket) would have to be redesigned if the goal is a soft landing, otherwise the falling barge would certainly destroy the rocket and possibly itself. This comic was published on the week following SpaceX's Iridium 1 mission , where the first stage of the rocket which delivered 10 satellites into orbit successfully landed on a barge near California. This was filmed from the returning stage 1 and also from further away . More details of the launch are available here . It marked the seventh time SpaceX successfully landed and recovered its booster on a commercial mission. [There is one panel in this comic with the main drawing at the bottom. Two smaller drawings are inserted above this drawing to explain the idea.] [The first insert shows a barge with no center and a large piece of paper with the SpaceX logo above the barge.] [The second insert shows the paper stretched over the hole.] [The main drawing at the bottom shows a cross-section of the barge in water, showing there is only water below the paper. Above the paper the large first stage, without the top part with the payload, of a reusable rocket is attempting to land on the paper on the SpaceX logo (not visible in this view). It is still so high above the fake barge that the exhaust fire below the rocket is nowhere near the paper.] [Caption below the panels:] My hobby: Hollowing out the center of a barge, stretching paper over the hole painted with the SpaceX logo, and leaving it floating offshore near launch sites.

Phone Numbers

Phone Numbers

https://www.xkcd.com/1789

https://www.explainxkcd.com/wiki/index.php/1789:_Phone_Numbers

[White Hat is looking at a smartphone held out by Cueball.] Cueball: I have five phone numbers for you. Which one should I use? White Hat: That first one is my cell - you should use the Google Voice one, since it will forward to my laptop if I'm on WiFi. #5 is my work number, which just forwards to #1. #3 should always work but can't do texts. White Hat: You can delete #4. I think. [Caption below the frame:] Another reason I never call people.

Cueball , who again represents Randall as given from the caption below the comic, has several phone numbers stored for White Hat under his contact entry on his phone and asks him which number he should generally use. Often, people who have known each other for a long time may have old information recorded for each other, which may no longer be accurate. For instance, if they know each other from when cell phones were still rather new, they would have had a home phone number also. More and more people have discontinued their land lines and now only keep the cell phone number. Cueball has five numbers for White Hat, listed here as #1 to #5 as they are numbered in the comic (and not the order he mentions them): White Hat does say that Cueball should use #2, the Google Voice number. This is a telephone service that provides call forwarding and voicemail services, voice and text messaging for Google customers. Google is updating Google Voice so that is probably the reason for the comic as the update came out rather late on the day when Google made the announcement of the update. However, he then makes it clear that this will only work when he is online with his laptop on a WiFi connection. This could be his way of saying that he only wishes to talk to Cueball when he is in such a position. However, he also explains the other numbers more or less making it clear how he could be reached. And all in all it seems like his cell phone is still the best way to reach him. Today on smartphones it could be possible in your contact list to save such tedious details about each number (such as "should always work but doesn't accept texts.") But who wishes to do so? Also not all cell phones do have this option, and maybe at best you can only label the numbers as "work", "home" or "cell" but not to the detail that White Hat provides. In the caption below Randall explains that this kind of trouble with getting the correct number for people he wish to contact is one (another) of more (several?) reasons he never calls people. Today there are so many other methods of getting into contact, also even if texting is out of the questions as well. Skype, messenger, other social networking platforms like Facebook and of course the old way of sending a letter or talking in person... White Hat's answer reveals a complicated history of communication practices. This cobbled-together personal technology is a common theme for Randall, see 1254: Preferred Chat System for another example, where Voicemail, text and Google Voice is also mentioned (and mixed in with written letter if not real mail). The title text must refer to one of the five numbers saying that texting works for one of the numbers. This should then not be #3. It could be the number he says Cueball should use #2, but it seems more likely that it is an amendment to the last I think for #4. Maybe he realizes that this is the number he used to receive text on, when his #3 number was all he had and since that could not receive text he got the number which is now #4. In either case the number he talks about can in fact receive text - but if #4 it can probably not receive phone calls. And then it gets weird because if the text gets too long then the message goes to voicemail . This is of course nonsense as a text message cannot just turn in to a spoken message. (Though of course there are text-to-speech programs, but as this takes up more space than text on a server, it would make no sense). To cap it up, just in case it did turn into a voicemail, it would not make any difference because White Hat has been locked out of his voicemail. It is not uncommon that young people never use voicemail and expect people to text them rather than leave a message. This could be a problem for them if "old" people call to let them know of a job they have been offered etc. So it is likely that Randall also jokes about this by letting White Hat be indifferent to having been locked out of his voicemail. [White Hat is looking at a smartphone held out by Cueball.] Cueball: I have five phone numbers for you. Which one should I use? White Hat: That first one is my cell - you should use the Google Voice one, since it will forward to my laptop if I'm on WiFi. #5 is my work number, which just forwards to #1. #3 should always work but can't do texts. White Hat: You can delete #4. I think. [Caption below the frame:] Another reason I never call people.

Sad

Sad

https://www.xkcd.com/1790

https://www.explainxkcd.com/wiki/index.php/1790:_Sad

[Cueball is walking up to Ponytail who sits at her desk in an office chair typing on her computer.] Cueball: How are you doing? Ponytail: Hah. Cueball: You seem distant lately. For the past few months. Ponytail: Can't imagine why. [Cueball talks to Ponytail at her desk from off-panel.] Cueball (off-panel): Your projects have stagnated. Ponytail: But my Stardew Valley farm is doing great . Cueball (off-panel): You can't just hide from everything. Ponytail: Fact check : Mostly false. [In a frame-less panel Cueball is seen standing behind Ponytail at her desk.] Cueball: I'm glad you're including more comments in your code, but it would be nice if they were comments about your code. Cueball: Or at least a bit less obscenity-filled. Ponytail: Look, they say to write what you know. [Cueball leans forward towards Ponytail at her desk (who has looked on the screen in the same position through the entire comic).] Cueball: All the functions you've written take everything passed to them and return it unchanged with the comment "No, you deal with this." Ponytail: It's a functional programming thing. Avoiding side effects. Cueball: You avoid all effects. Ponytail: Only way to be sure.

The comic is about Cueball confronting Ponytail over her recent behavior and poor emotional state over the past few months. While Ponytail doesn't give any details on what's causing it, it can be inferred that she is referring to the recent election of Donald Trump as President of the United States , which happened about 2 months prior to the publication of this comic. This is a common reaction in the United States whenever a new president is elected, as the voters who did not vote for the new/upcoming President will be feeling unpleasant emotions that their chosen candidate did not win, and will want to express these emotions to the wider world. With the advent of the internet, and more recently social media, the expressions of these emotions have grown more common and often more hyperbolic, regardless of the quality of the candidate. Ponytail has retreated to video games for solace to the point that her real life projects are suffering. Stardew Valley is a video game in which a player creates and manages a virtual farm. And when Cueball mentions that her projects have stagnated, she retorts that her farm in the game is doing great. A comic with the name of that game was releases only two weeks later, 1797: Stardew Valley , indicating that it is indeed Randall who has played this game excessively. Cueball's statement about not being able to hide from everything is a common one to give to insecure people or to those trying to run away from their problems. Ponytail's reply is in the form of a PolitiFact reply, claiming (possibly quite truly) that such assertions are mostly false , one of the six options, but it is far from being the worst, thus acknowledging that you can't hide from everything, just mostly. Politifact.com was also the subject of an earlier comic, 1712: Politifact . In computer programming, comments are pieces of non-functional, descriptive text that programmers include in their code. Typically, they are used as a form of documentation, to make the code easier for other developers to understand. This is why Cueball is glad that Ponytail is at least writing more comments; documentation is something that's often neglected by developers, despite its usefulness. Unfortunately, the comments that Ponytail is putting in her code are not actually about the code at all; she is, presumably, commenting more generally on whatever is troubling her as a way of venting her issues. Ponytail's reply to "write what you know" is a common piece of advice given to amateur fiction writers - it means that writers tend to write best when they are writing about something they personally know well, since they will have plenty of interesting and useful experience to draw from. However, since Ponytail's comments are full of obscenities, she is sarcastically suggesting that obscenity is all she currently knows. Functions are reusable pieces of code which developers create to avoid repetition and make the code more organized. For example, if the code often has to calculate the distance between two points, it makes sense to place that calculation logic into a "calculateDistance" function, which can then just be called whenever it is needed. More generally, a function accepts inputs (eg. the coordinates of two points) and may return an output (eg. the distance between the two points). Cueball notes, however, that all of the functions Ponytail has written are not actually doing anything with their inputs; they are just returning them straight back again and demanding that the calling code should deal with the problem itself. This makes the functions practically useless. Ponytail sardonically tries to justify this as a functional programming technique by saying that she is "avoiding side effects". A side effect is a situation in programming in which an isolated piece of code changes something about the global state of the program - this can be problematic, as there could be other parts of the code that were not expecting the change, and might behave differently as a result. Their different behavior is a side effect . Sometimes side effects are intentional, but when they are not, they can be tricky to debug and fix. Functional programming is a programming paradigm in which most or all computation is performed within the scope of self-contained functions, thus avoiding stateful behavior entirely. This removes the possibility of any side effects, since each function only knows what it is told via its inputs, and does not need to be concerned with anything happening outside of itself. Technically, Ponytail is adhering to this paradigm, but only in the sense that her functions are not doing anything at all , and so cannot have side effects. Cueball fairly makes this point by noting she is avoiding all effects, to which Ponytail quotes part of a famous quote from Ripley in Aliens : I say we take off and nuke the entire site from orbit. It's the only way to be sure . By replying that it's the " only way to be sure " she is thus indirectly saying better safe than sorry, but in reality she just doesn't care about her programming anymore because of her sad state of mind. The title text is a pun, interpreting the phrase "side effect" literally. If you turn an object 90 degrees along the right axis you will place it on its side, so thus making it a effect of putting something on its side, or a "side effect." You can also turn 90 degrees (along another axis), facing what was previously your side. Sadness could come from many causes (breaking up, family member dying etc). However, the notion that this comic is political is supported by the fact check in the second panel, and also that this was only the second comic released after Donald Trump 's inauguration . This comic gave rise to this page: Sad comics . It was the fourth very sad/negative comic in a bit more than two months after the election and the page describes the relations of these comics and others which relates to election or politics related to Donald Trumps presidency. [Cueball is walking up to Ponytail who sits at her desk in an office chair typing on her computer.] Cueball: How are you doing? Ponytail: Hah. Cueball: You seem distant lately. For the past few months. Ponytail: Can't imagine why. [Cueball talks to Ponytail at her desk from off-panel.] Cueball (off-panel): Your projects have stagnated. Ponytail: But my Stardew Valley farm is doing great . Cueball (off-panel): You can't just hide from everything. Ponytail: Fact check : Mostly false. [In a frame-less panel Cueball is seen standing behind Ponytail at her desk.] Cueball: I'm glad you're including more comments in your code, but it would be nice if they were comments about your code. Cueball: Or at least a bit less obscenity-filled. Ponytail: Look, they say to write what you know. [Cueball leans forward towards Ponytail at her desk (who has looked on the screen in the same position through the entire comic).] Cueball: All the functions you've written take everything passed to them and return it unchanged with the comment "No, you deal with this." Ponytail: It's a functional programming thing. Avoiding side effects. Cueball: You avoid all effects. Ponytail: Only way to be sure.

Telescopes Refractor vs Reflector

Telescopes: Refractor vs Reflector

https://www.xkcd.com/1791

https://www.explainxkcd.com/wiki/index.php/1791:_Telescopes:_Refractor_vs_Reflector

[A one panel comic showing two different telescope designs next to each other with labels above them and a bullet list of points below them. The left drawing will be described first then the right.] [Left:] Refractor [A slim telescope design is shown. At the top the light enters shown in a light yellow shade between two thin parallel light gray lines that just fits inside the opening of the telescope which is slightly wider at the top than at the lens sitting a short way into the opening. The lens causes the light to focus just where the telescope again changes dimensions, and the light enters a small opening at the bottom of the long pipe of the telescope. Here the yellow light is a point as the two gray lines cross each other at that point. The light then broadens slightly again and the thin yellow light cone hits a mirror at the bottom of the telescope and is reflected to the left and out through the eyepiece. Below are the following points:] More expensive Less compact Chromatic aberration Reduced light-gathering [Right:] Reflector [A much broader (more than 150% of the first) but also much shorter (66%) telescope design is shown. At the top the light enters shown in a light yellow shade between two thin parallel light gray lines that still just fits inside the opening of the telescope. On it's way down to the bottom of the telescope the light passes by a small mirror turned down towards the bottom. When the hits the curved bottom mirror light is focus on it's way back back and a small light cone hits the small mirror mentioned before sitting almost at the top of the telescope. This mirror reflects the light to the left into an even thinner light cone that goes out through the eyepiece located near the top of the telescope. Below is the following point:] Can't see space vampires In an earlier version of this comic, the eyepiece of the refracting telescope included a mirror, often used with refractors to give an upright image and more comfortable access for the observer. This would of course invalidate the only advantage it has (vampire-visibility) over reflecting telescopes. Randall later corrected this so the current/final version shows the light going straight out of the end. An amici roof prism is sometimes used instead of a mirror with refractors, because it does not only deliver an upright image, but also one that is not a mirror image. In a prism, there is only total reflection, which, as opposed to a metal mirror, would probably work on vampires.

This comic compares two major types of optical telescopes : The refracting telescope and the reflecting telescope . A refracting telescope produces an image with a series of lenses. A reflecting telescope uses mirrors. (A third type, the catadioptric system telescope, uses both mirrors and lenses. It is not shown here.) It first looks like the comic is simply trying to show that refracting has many flaws, such as expense, size and visibility (see more details below ). However, the punchline invalidates these complaints with the (apparently major) flaw listed with the reflecting telescope: It can't see space vampires . The unstated reason for this is that vampires , according to some cultures , cannot be seen in a mirror. As Space Vampires (like earth vampires) are widely believed to be made up and thus unlikely to interest most stargazers , [ citation needed ] this complaint is superfluous, and the reflecting telescope effectively has no flaws in comparison to the refracting telescope. There are other problems, though, with reflecting telescopes see details below . (Also there was a big problem in the original version of this comic ). Frequently, however, the right-angle transition at the base of the refractor telescope is done with a prism (an "image erector"). This uses the optical principle of total internal reflection. If mirror-non-appearance of vampires is due to the interaction of evil with silver, a refractor using a prism could still see vampires. On this theory, however, the reflector could too, since modern astronomical mirrors are coated with aluminum, not silver. The title text expands on the seeing of supernatural beings, as another negative point is added to the refracting telescope; it apparently can't see Shadow People or the Slavic god Chernabog (sometimes spelled Chernobog), both of which are important although clearly not as important to the telescope's merit as seeing vampires since the fact is only mentioned in the title text. So of course the refracting telescope is still the best. Of course also neither the shadow people nor the god exists [ citation needed ] so this would likewise be a moot point. In reality, "shadow people" are a psychological phenomenon wherein humans ascribe human shapes and movements to shadows in dark spaces. Chernobog is a 12th century Slavic deity, whose name translates to black god . His most famous appearance in modern media was in the 1940 Disney movie Fantasia (and Disney merchandise is also almost the only place that his name is spelled as Randall spelled it, with an "a" in the middle). Because shadows are dark and the god is also dark, they cannot be seen by the refracting telescope due to the reduced light-gathering which has already been mentioned as a drawback in the main comic. Telescopes have been the subject of many comics on xkcd. Recently one about space telescope was released 1730: Starshade and before that a large "private" telescope was shown in 1522: Astronomy . The basic performance of a telescope is determined by its size: a wider telescope catches more light, making it easier to see faint objects, while a longer telescope is better for high magnification viewing. For looking at stars, the width is actually more important. No matter how much you zoom, a star is too far away to make bigger, but with a big aperture, you can see stars too faint for the naked eye. Planets benefit more from magnification, and distant galaxies need both. In both respects, it's much easier to make a big reflector telescope than a big refractor one. Since a lens can only be held in place by its edge, the center of a large lens sags due to gravity, distorting the images it produces. This means most refractor telescopes make do with narrow apertures only a couple of inches across. Reflector telescopes are sometimes called "light buckets" because they can have extremely big openings that can catch light from even very faint stars. In addition, because it has a mirror at one end, the reflector telescope is, in effect, twice as long as it appears - a refractor just cannot compete. Refracting telescopes were only gradually overtaken by reflecting telescopes, however. In the age of great refractors , the largest telescopes in the world were refractors. Reflectors at the time had mirrors surfaced in speculum metal that began to tarnish only months after application, negatively affecting telescope performance. This problem was resolved when it became possible to surface a mirror in silver, but the problems with refractive lenses persist. Because of this, the largest optical telescopes ever built are reflectors, rather than refractors. In addition, a liquid mirror telescope uses a very cheap, but potentially very large mirror - with the drawback that the telescope can only look straight upwards. Randall's points: Other problems not mentioned by Randall: It is worth noting that (apart from the vampire problem) a reflecting telescope also has disadvantages compared to a refracting telescope: Despite this disadvantage, reflecting telescopes are used almost exclusively in modern astronomy because of practical limitations in making large refracting telescopes. Very few amateur astronomers use refracting telescopes - nowadays, they mostly exist to con people looking for Christmas presents in department stores (just because a telescope promises 100x zoom doesn't mean the image quality is any good!) On the other hand, reflecting telescopes help astronomers gaze at Beige Gorgons (mentioned in comic 2360: Common Star Types ). [A one panel comic showing two different telescope designs next to each other with labels above them and a bullet list of points below them. The left drawing will be described first then the right.] [Left:] Refractor [A slim telescope design is shown. At the top the light enters shown in a light yellow shade between two thin parallel light gray lines that just fits inside the opening of the telescope which is slightly wider at the top than at the lens sitting a short way into the opening. The lens causes the light to focus just where the telescope again changes dimensions, and the light enters a small opening at the bottom of the long pipe of the telescope. Here the yellow light is a point as the two gray lines cross each other at that point. The light then broadens slightly again and the thin yellow light cone hits a mirror at the bottom of the telescope and is reflected to the left and out through the eyepiece. Below are the following points:] More expensive Less compact Chromatic aberration Reduced light-gathering [Right:] Reflector [A much broader (more than 150% of the first) but also much shorter (66%) telescope design is shown. At the top the light enters shown in a light yellow shade between two thin parallel light gray lines that still just fits inside the opening of the telescope. On it's way down to the bottom of the telescope the light passes by a small mirror turned down towards the bottom. When the hits the curved bottom mirror light is focus on it's way back back and a small light cone hits the small mirror mentioned before sitting almost at the top of the telescope. This mirror reflects the light to the left into an even thinner light cone that goes out through the eyepiece located near the top of the telescope. Below is the following point:] Can't see space vampires In an earlier version of this comic, the eyepiece of the refracting telescope included a mirror, often used with refractors to give an upright image and more comfortable access for the observer. This would of course invalidate the only advantage it has (vampire-visibility) over reflecting telescopes. Randall later corrected this so the current/final version shows the light going straight out of the end. An amici roof prism is sometimes used instead of a mirror with refractors, because it does not only deliver an upright image, but also one that is not a mirror image. In a prism, there is only total reflection, which, as opposed to a metal mirror, would probably work on vampires.

Bird/Plane/Superman

Bird/Plane/Superman

https://www.xkcd.com/1792

https://www.explainxkcd.com/wiki/index.php/1792:_Bird/Plane/Superman

This comic is a logical comparison of observations to resolve the classic Superman catchphrase of comic book bystanders: "Look, up in the sky... It's a bird !... It's a plane !... It's Superman !", hence the title. Superman, a character originally created for comic books in the 1930s, is an alien with superpowers, including the power of unaided flight; hence the catchphrase exclaiming peoples' amazement. At the correct distance both birds, planes and the fictional Superman could be mistaken for each other. So this comic aims to help people identify the airborne object by listing on which properties they are alike and on which they are different. This problem was also mentioned in the title text of 1633: Possible Undiscovered Planets , putting Superman near the bird/plane boundary explaining why all this confusion has arisen. The observations compared range from the mundane to the bizarre and they are listed and explained below in the table . Here some highlights are mentioned, but for all these there are much more detail below. Some of the mundane observations are that birds don't fly around with people, while Superman can do it, and planes are meant for it; and that the latter two are new "inventions", whereas birds have flown around for millions of years. Interestingly enough there are actually two observations that have check mark for all three; the first being that there are enthusiasts for all three different flying objects. And these will obsess over small color details in otherwise similar looking objects. The other common thing is that they all may have sex in midair. The possibility of that happening for the all three are discussed in the table. Three observations only counts for birds, where all those that do not count for birds do count for both planes and superman. Two of these relates to the fact that birds are eaten by cats and humans, the last is that birds flap their wings to fly, the others have other means of flight. There are observations that rules out only planes or only superman, but none that rules out only one of them at the same time as birds are ruled out. There are also three direct jokes towards the bottom. The first is that David Attenborough may also have observed Superman's mating habits just like he has with birds in the documentary series The Life of Birds . The second is that not only birds poop in flight, but that Superman could and would also do so. And the third (and also final observation) is that not only birds chase insects to eat them, but Superman also chases them... though only when he is bored. These last three observations have that in common that the planes are left out of all of them, and the joke is always on Superman. As it has been before in 1384: Krypton and 1394: Superm*n (released just ten comics apart). The title text refers to black stickers (decals) in the shape of an easily recognizable predatory bird, like falcons to enhance the visibility of clear glass windows or doors and scare smaller birds away before they crash into the window. This may actually not work very well according to this article: Why Birds Hit Windows , where a falcon decal is also shown. But they are meant to warn birds away and according to this comic they could also prevent Superman from flying through your window (and thus also stop him from possibly just continuing through the building). They are not known to affect the risk of airplanes flying into the building. [ citation needed ]

Soda Sugar Comparisons

Soda Sugar Comparisons

https://www.xkcd.com/1793

https://www.explainxkcd.com/wiki/index.php/1793:_Soda_Sugar_Comparisons

[Above the four rows of two panels with captions above them are the following title and note:] Soda Sugar Comparisons See also xkcd.com/1035 [Above the two columns of panels are the following captions for the left and right column:] In terms of sugar, drinking this much soda... ...is equivalent to eating this: [In the first rows left panel there is a drawing of a bottle with a screw cap and label. The content in the bottle is gray, as is the cap. The air above the liquid in the bottle beneath the cap as well as the label are light gray and the label is empty of text. The following text is written on three lines left of the bottle next to the label:] One 20 oz soda bottle ( e.g. Coca Cola ) [In the opposite first row right panel there are two drawings. First three gray eggs are placed in a small pyramid. A thin line goes down the lang axis of the eggs. Text on two lines is below the eggs. Next to the eggs is a long gray bar standing up. It has wiggly lines for giving its surface features along its entire length. Two lines at the top and bottom are used to measured the length with two arrows pointing to either line, which are then going to the text next to the bar which are thus in between the arrows, taking up five lines.] 3 Cadbury eggs... ...Or a Snickers bar the length of the bottle. [In the second rows left panel seven soda bottles are drawn like the one in the first panel (as are all later bottles). They are standing close to each other. Along the bottom of all the bottles is the following text:] One soda per day for a week [In the opposite second row right panel there is a drawing of a bottle with light gray content being poured out of the open bottle down in to a small pile next to the screw cap lying below the open bottle. The content is obviously not liquid but rather oozing frosting being dumped out of the bottle not ending up in a puddle but in a taller structure with jagged edges. A bit of the oozing material hangs far out of the bottle without dropping. Also the light gray content in the bottle is uneven with darker and brighter patches. Below and left of the screw cap and pile of goo there are two lines of text:] One bottle of cake frosting [In the thirds rows left panel a soda bottle is drawn next to two rows of three full month calendar pages, which takes up the same height as the bottle. A text below the pages takes up two lines.]|| One soda per day for six months [In the opposite third row right panel there drawings of four large transparent plastic milk jugs filled to the to the brim with something that is a mixture between gray and white in small clumps. Two of the jugs are in front of the other two, and covers all but the top of the one between them and half of the last which extends right of the other two. Leaning up against the rightmost jug is a dark gray pack of candy with the candy name written in white on the open pack, and more unreadable white text is at the top of the pack. Next to the pack lies five candy pieces, three in front and two to the right. These candy pieces are dark gray (three) or light gray (two). There is a line of text beneath the jugs:] Label: Skittles Four gallons of Skittles [In the fourth and final rows left panel one soda bottles is next to three rectangles on top of each other with a year given in each. Beneath the drawing there is a text over two lines:] 2017 2018 2019 One soda per day for three years [In the opposite fourth row right panel there is a drawings of a convenience store counter with three cashiers behind it at their cash register with payment terminal close by each of them as well. From left to right they are Ponytail, Cueball and Megan. the cash registers are to the left for all of them, with terminal next to it for Ponytail and on the other side for the other two. Between the two outer and the middle cashier, there are two signs on high poles with unreadable text. One is close to Ponytail the other is in the middle of the other two. Beside Cueball there is an additional flat thing which could be a candy weight. To Megan's right there is a square thing on top of which something sticks up in several layers. It could be a box of Kleenex. On four rows of shelves under the disc various items are closely stacked, so they cannot be separate from one another. It in though possible from white rows with prices to see that there are four rows. Underneath this drawing there is a text in two lines:] A convenience store's entire 20-foot candy counter

This comic is one of the rare incidences where the title is actually written at the top of the comic. It is also a rare example where an old comic, 1035: Cadbury Eggs , is directly referenced, and even at such a prominent place, albeit in a faded down gray font. In the comic, Randall compares soda's sugar content to different types of sugary food (see trivia ). The first two panels compare the sugar content of a 20 oz bottle of soda (i.e. 591 mL, thus almost like a half liter bottle) to three Cadbury eggs or one Snickers bar if it had the length of the bottle (9 inches or about 23 cm; most actual Snickers bars are only 4 inches or 10 cm, though the company does manufacture various "king" sizes). In the next row, Randall compares one bottle of soda each day of a week (seven bottles) to a bottle of cake frosting . Continuing the estimations in the third row, Randall states that one soda a day for six months will provide the same amount of sugar as four gallons of Skittles (15.1 liters). Finally, Randall compares three years' worth of daily sodas contains as much sugar as a convenience store's 20-foot (6.1 m) long candy counter . The reference to Cadbury Eggs is of course the topic of the referenced comic 1035: Cadbury Eggs , which has the same comparison between soda's sugar content and Cadbury Eggs, as well as comparing a number of other substances to the eggs. So that comic goes the other way around. In the title text, it is stated that the key is portion control, which sounds normal until it is revealed that the portion control is actually for frosting instead of soda. Eating frosting out of cans is also referenced in the title text of 418: Stove Ownership . Of interest in this case is that the American Heart Association recommends less than 20-36 grams per day for a sedentary lifestyle (7.5 to 9 MJ per day). [Above the four rows of two panels with captions above them are the following title and note:] Soda Sugar Comparisons See also xkcd.com/1035 [Above the two columns of panels are the following captions for the left and right column:] In terms of sugar, drinking this much soda... ...is equivalent to eating this: [In the first rows left panel there is a drawing of a bottle with a screw cap and label. The content in the bottle is gray, as is the cap. The air above the liquid in the bottle beneath the cap as well as the label are light gray and the label is empty of text. The following text is written on three lines left of the bottle next to the label:] One 20 oz soda bottle ( e.g. Coca Cola ) [In the opposite first row right panel there are two drawings. First three gray eggs are placed in a small pyramid. A thin line goes down the lang axis of the eggs. Text on two lines is below the eggs. Next to the eggs is a long gray bar standing up. It has wiggly lines for giving its surface features along its entire length. Two lines at the top and bottom are used to measured the length with two arrows pointing to either line, which are then going to the text next to the bar which are thus in between the arrows, taking up five lines.] 3 Cadbury eggs... ...Or a Snickers bar the length of the bottle. [In the second rows left panel seven soda bottles are drawn like the one in the first panel (as are all later bottles). They are standing close to each other. Along the bottom of all the bottles is the following text:] One soda per day for a week [In the opposite second row right panel there is a drawing of a bottle with light gray content being poured out of the open bottle down in to a small pile next to the screw cap lying below the open bottle. The content is obviously not liquid but rather oozing frosting being dumped out of the bottle not ending up in a puddle but in a taller structure with jagged edges. A bit of the oozing material hangs far out of the bottle without dropping. Also the light gray content in the bottle is uneven with darker and brighter patches. Below and left of the screw cap and pile of goo there are two lines of text:] One bottle of cake frosting [In the thirds rows left panel a soda bottle is drawn next to two rows of three full month calendar pages, which takes up the same height as the bottle. A text below the pages takes up two lines.]|| One soda per day for six months [In the opposite third row right panel there drawings of four large transparent plastic milk jugs filled to the to the brim with something that is a mixture between gray and white in small clumps. Two of the jugs are in front of the other two, and covers all but the top of the one between them and half of the last which extends right of the other two. Leaning up against the rightmost jug is a dark gray pack of candy with the candy name written in white on the open pack, and more unreadable white text is at the top of the pack. Next to the pack lies five candy pieces, three in front and two to the right. These candy pieces are dark gray (three) or light gray (two). There is a line of text beneath the jugs:] Label: Skittles Four gallons of Skittles [In the fourth and final rows left panel one soda bottles is next to three rectangles on top of each other with a year given in each. Beneath the drawing there is a text over two lines:] 2017 2018 2019 One soda per day for three years [In the opposite fourth row right panel there is a drawings of a convenience store counter with three cashiers behind it at their cash register with payment terminal close by each of them as well. From left to right they are Ponytail, Cueball and Megan. the cash registers are to the left for all of them, with terminal next to it for Ponytail and on the other side for the other two. Between the two outer and the middle cashier, there are two signs on high poles with unreadable text. One is close to Ponytail the other is in the middle of the other two. Beside Cueball there is an additional flat thing which could be a candy weight. To Megan's right there is a square thing on top of which something sticks up in several layers. It could be a box of Kleenex. On four rows of shelves under the disc various items are closely stacked, so they cannot be separate from one another. It in though possible from white rows with prices to see that there are four rows. Underneath this drawing there is a text in two lines:] A convenience store's entire 20-foot candy counter

Fire

Fire

https://www.xkcd.com/1794

https://www.explainxkcd.com/wiki/index.php/1794:_Fire

[The comic shows the top part of the front page of a folded newspaper. The main headline is the only readable with a photo covering half of the pages below. In the photo a factory is on fire, with sound waves emanating to all sides. There are several sections with unreadable text.] 50,000-Alarm Fire at Alarm Factory

In the United States and Canada, the term multiple-alarm fire is used to categorize the level of response to fires by local authorities, for instance how many units responded to the alarm. The range typically only goes through a small number of levels: typically a one-alarm fire, two-alarm fire, and three-alarm fire, perhaps up to five or six alarms in some cities, though a ten-alarm fire did occur near where Randall lives two months before the comic. In the comic, a newspaper front page is shown with its cover story reporting a "50,000-alarm" fire, with a picture of a factory on fire. The humor lies in the unusual use of the term. Instead of indicating the severity of the fire, the number merely indicates the number of alarms being manufactured or stored in the factory at the time of the fire. As indicated by the sound waves, or agitrons, shown in the image, at least some of those alarms appear to have been set off. It is unclear what the causal relationship between the alarms and the fire is. The presence of fire might have activated those alarms (e.g. if they are smoke detectors), the sounding of alarms might have caused the fire to start (e.g. due to workers' attention being diverted from other critical operations), or they might be unrelated events that happened at the same time. The title text mentions the musician Billy Joel being detained briefly as a suspect for the fire. But he was quickly released, likely because he didn't start the fire , which is a reference to his song " We Didn't Start the Fire ". In other words, Billy Joel's claim that he is not responsible for the fire at the alarm factory has been taken seriously enough for him to be released. Also, the reference is humorous because it compares the literal fire depicted in the factory to the metaphorical fire in people's hearts, in the song. (Or just ignores the fact that the song's fire was metaphorical, for the sake of the joke.) The incident where Billy Joel got arrested for arson was earlier shown on a similar folded newspaper with only one line of text visible next to an image. This was in comic #4 of 821: Five-Minute Comics: Part 3 . This all fits together as the cover of the single is also a newspaper page with a picture of Billy Joel beneath a headline which is the title of the song. The column of text to the right of the picture is readable here. It is not easy to read it through as some of the text continues outside the image. (The text is a section of the lyrics for the song starting from "Richard Nixon" after the fourth chorus continuing in to the next chorus). The lyrics of the song is also mentioned in 1775: Things You Learn . That Billy Joel was released is also obvious since he has also sung the song An Innocent Man , where he sings I am an innocent man, Oh yes I am . [The comic shows the top part of the front page of a folded newspaper. The main headline is the only readable with a photo covering half of the pages below. In the photo a factory is on fire, with sound waves emanating to all sides. There are several sections with unreadable text.] 50,000-Alarm Fire at Alarm Factory

All You Can Eat

All You Can Eat

https://www.xkcd.com/1795

https://www.explainxkcd.com/wiki/index.php/1795:_All_You_Can_Eat

[The comic shows the facades of four stores next to each other on a street, with the sidewalk shown in front of them. To the top of each store's name there has been appended white signs. Three of the white signs partially cover the name part of the sign above three of the stores, but the fourth sign is placed entirely above the text of the third store. Thus that white sign's top is higher up than the building's.] [First store from the left. The top line of two on the store's sign is obscured by the white sign:] White sign: All-you-can-eat Store sign: Discount Tires [Second store from the left. The top line of two on the store's sign is obscured by the white sign:] White sign: All-you-can-eat Store sign: Hair Salon [Third store from the left. The white sign on this store is slightly tilted, and most of it is above the top of the store completely above the store sign:] White sign: All-you-can-eat Store sign: Lumber and Store sign: Flooring Depot [Fourth store from the left. The top line of two on the store's sign is obscured by the white sign. However, the name can still be deduced, and the top line says "Kevin's".] White sign: All-you-can-eat Store sign: Pet Store [Caption below the frame:] My hobby: Going out at night and adding "all-you-can-eat" to every store's sign

An all-you-can-eat buffet is when a restaurant will charge you once for entry and then continuously serve you more food at no additional cost until you have eaten all-you-can-eat. Part of the " My Hobby " series, this comic shows Randall wishes to pre-pend "all-you-can-eat" to random stores. With the exception of the pet store, which sells pet food, these stores do not sell food, so the very idea of eating their product would be ridiculous for most humans. However, this is what Randall's stunt makes the stores he defaces seem to advertise. Most people would not seriously consider eating the products these stores sell [ citation needed ] even with the signs suggesting they should, as they sell tires , hair cuts , lumber and flooring and pets . The "all-you-can-eat" signs obscured the top line for three of the four shops signs. It is not really possible to read the obscured part of the first two signs, although it is likely that the first and last letters in the first sign are A and K. And also since the A is taller than the white sign, this first letter must be larger than the others which do not show above the white sign. There could be room for anything from 8 to many more letters hidden as it can be seen in the second line below that the I's take up much less space than the other letters. But from the letters below it seems likely there were 9 (maybe including a space) if no I's were used resulting in a word or two like this "A _ _ _ _ _ _ _ _ _ K". All letters in the comic seems to be capital, but Randall sometimes use small caps, where the first capital letter is larger than the others. This would fit with this sign. The third sign is fully visible, and it makes sense as it is not a name in the top line but part of the description of what the store provides. The last sign is though clearly readable even though the white sign covers the name at the top, and it says "Kevin's Pet Store". There actually exists a web page with the name "Kevin's Pet Shop" , supposedly located in Texas, but there is very limited information on the page. See more about the use of Kevin in xkcd in the trivia below. In the title text, Randall seems to have fallen for his own prank. After he puts the "all-you-can-eat" sign onto the signmakers' place, he proceeds to heed his own sign literally and eat the posterboards that he is supposed to make signs from. To remind himself not to make the same mistake again, he tells himself to "do the sign-making place last." It should also be noted that sometimes "all-you-can-eat" is used to mean "unlimited usage". An all-you-can-eat data plan, for example, is another way to say unlimited data. If this definition of the word were used, all-you-can-eat would mean "unlimited copies of our product for a one time fee". A kapsalon can, arguably, also be called an all-you-can-eat hair salon. Note that some pets are considered food in some cultures; rabbits are commonly kept as pets as well as served as food, dogs are consumed in some areas in eastern Asia, guinea pigs in South America and Africa, and some fictional characters are known for eating cat. Even more normally, a cat owner that wants to buy an "all you can eat" bird feast for their cat would be happy with this last store. Aside from pets, pet stores also sell pet food, and while frowned upon by some, it is common practice to give human nutrition supplements to pets and vice versa. Some animal snacks are considered very tasty by many people, and there even exist several brands of snacks designed to be eaten both by people and their pets so that the owners could feel somehow closer to their beloved companion. Premium pet foods are made to standards that are no worse than standards for human food, so eating them poses no health risks in the short term - long term, most pet diets would fail to deliver the right balance of nutrients needed by humans. [The comic shows the facades of four stores next to each other on a street, with the sidewalk shown in front of them. To the top of each store's name there has been appended white signs. Three of the white signs partially cover the name part of the sign above three of the stores, but the fourth sign is placed entirely above the text of the third store. Thus that white sign's top is higher up than the building's.] [First store from the left. The top line of two on the store's sign is obscured by the white sign:] White sign: All-you-can-eat Store sign: Discount Tires [Second store from the left. The top line of two on the store's sign is obscured by the white sign:] White sign: All-you-can-eat Store sign: Hair Salon [Third store from the left. The white sign on this store is slightly tilted, and most of it is above the top of the store completely above the store sign:] White sign: All-you-can-eat Store sign: Lumber and Store sign: Flooring Depot [Fourth store from the left. The top line of two on the store's sign is obscured by the white sign. However, the name can still be deduced, and the top line says "Kevin's".] White sign: All-you-can-eat Store sign: Pet Store [Caption below the frame:] My hobby: Going out at night and adding "all-you-can-eat" to every store's sign

Focus Knob

Focus Knob

https://www.xkcd.com/1796

https://www.explainxkcd.com/wiki/index.php/1796:_Focus_Knob

[Caption above the drawing:] Personal Focus [A gray rotary control knob with the range of options divided by small ticks on a black semi. The knob has a black line that indicates that the knob's setting. At the bottom left and right where the semi circle begins and ends there are two labels in normal black text:] Left: Detail-Oriented Right: Big Picture [Above and all along the black semi circle with the range, another semi circle is drawn in light gray. This has been divided into three sections, with two large sections left and right forming the actual semi circle with double arrow lines. There is a short section with no tick inside it between the two other sections. There are three labels for each of these section, with a line from the label down to the small section. All described here are drawn light gray color. Note that Randall has misspelled "existential".] Left section: Fiddling with email settings Right section: Panic and existental paralysis Small section: Healthy balance

The comic is a pun. Normally, a rotary control knob is used for adjusting parameters in instruments, and the parameter "focus" is used to adjust the focal length on microscopes, telescopes, and other lens-based equipment. Here, however, the "focus knob" is used for Randall's personal sense of focus -- that is, how focused he is on his work and productivity, with the extremes of focus being towards Detail-Oriented (small details) and the Big Picture respectively. (A similar knob was used in 1620: Christmas Settings ). The healthy balance, Randall suggests, is focusing mostly towards the Big Picture (two thirds of the way towards the Big Picture between ticks 24 and 25 out of 37), while keeping an eye on the details by still staying one third Detail-Oriented . Focusing too much on the big picture can ensure nothing gets done, leading to panic and existential paralysis . Unfortunately, the range of healthy balance appears to be vanishingly small and difficult to reach; additionally, if we assume the knob can only stop at the little ticks marked along the outside and that the boundaries are not inclusive, there is no way to set it in the window of Healthy Focus . While performing any task (including your daily life as well as editing explainxkcd), it is easy to get so lost in the details that you forget the big picture. It is also equally easy to think too much about the big picture and make vague plans while missing out on the details. It is clear that at the moment Randall is mainly focusing on the small details fiddling with his e-mail settings as the knob is set to the 13th tick only just past one third away from Detail-Oriented . He thus seems to try to avoid seeing the big picture right now, since it is his personal knob to set as he wishes. Existential paralysis stemming from Randall getting worried about realizing how serious the state of the world is today (at the time of the comics release) are a common punchline in xkcd. With all the crises going on around the world, people get bombarded with these negative stories if they follow the news, either on TV, in news papers of on any social media (See 1773: Negativity ), especially on Facebook (see 1761: Blame ). It can thus become very overwhelming, if people do not focus more on their e-mail settings! This goes especially in a time like this, where many panics on Facebook due to for instance wars and conflicts around the world (like in Syria ), talk about climate change , or all the executive orders currently being signed by the recently inaugurated President Donald Trump , who took office less than three weeks before this comic's release. See more about these issues and other recently released sad comics here . Getting too deep into all this could cause the kind of panic attacks that could lead to the existential paralysis mentioned on the right side of the knob. It is these that Randall may be trying to avoid by keeping his focus firmly in the realm of e-mail settings rather than anywhere near the big picture. The joke in the title text relates to Randall's use of an old fashioned analog control, probably a potentiometer , in the graphic versus a more electronically modern and efficient switching system. Randall imagines a replacement control using pulse-width modulation (PWM), which is a technique often used to control the regulation in electronic power supplies or the speed of electric motors with far greater power efficiency than simpler analog controllers. This technique consists of shifting between fully on and fully off states so that the average is the expected output, but no power is wasted by holding the control mechanism "partially on". For example switching back and forth between 0 and 1, spending half the time in each position will lead to a mean value of 0.5. To code 0.67 (the healthy balance ), Randall would have to spend more time in the extreme big picture position (67% of the time) than in the detail-oriented position. In the real world of course, a person switching so radically and completely between attention states might get diagnosed with some sort of mania . But the knob might just be switched between the dividers bordering the healthy zone, creating the perfect balance. [Caption above the drawing:] Personal Focus [A gray rotary control knob with the range of options divided by small ticks on a black semi. The knob has a black line that indicates that the knob's setting. At the bottom left and right where the semi circle begins and ends there are two labels in normal black text:] Left: Detail-Oriented Right: Big Picture [Above and all along the black semi circle with the range, another semi circle is drawn in light gray. This has been divided into three sections, with two large sections left and right forming the actual semi circle with double arrow lines. There is a short section with no tick inside it between the two other sections. There are three labels for each of these section, with a line from the label down to the small section. All described here are drawn light gray color. Note that Randall has misspelled "existential".] Left section: Fiddling with email settings Right section: Panic and existental paralysis Small section: Healthy balance

Stardew Valley

Stardew Valley

https://www.xkcd.com/1797

https://www.explainxkcd.com/wiki/index.php/1797:_Stardew_Valley

[Inside a slim frame at the top of the comic there is a caption:] Stardew Valley morning routine [Below this frame there are two rows each consisting of three small panels taking up the same width as the caption panel above:] [Cueball wakes and rises up from his pillow sitting beneath his blanket in his four poster bed with round knobs. He yawns with a hand to his mouth. Above him floats a large sound bubble:] Cueball: Yawn [Cueball walks to the right with a small watering can held in front of him.] [Cueball pours water from the can over the three small plants. A line goes from the water to another bubble:] Water: Splish [Cueball walks back to the left with the watering can.] [Cueball stops with the can right next to a sleeping cat, which has a speech bubble pointing to its head.] Cat: Z [Cueball proceeds to pour water on the cat which immediately jumps up away from him trying to escape as water cascades on it. Again there is a line from the water to a speech bubble, but both the cats angry sound and Cueball's comment is written without bubbles.] Water: Splish Cat: Mrowl!! Cueball: –Dammit.

Stardew Valley is an indie farming simulation role-playing video game published by Chucklefish Games . Just as in similar games like Farmville and Harvest Moon , the player takes the role of a farmer who establishes their own farm and performs everyday tasks such as watering plants , growing food, and tending to animals. Pelican Town , referenced in the title text, is a fictional village in this game. In this comic, Cueball begins his morning routine in a Stardew Valley session by waking up and watering some of his farm's plants. However, he then walks up to a sleeping cat, pauses for a moment, then pours water on it, startling it awake. He says "Dammit!" to this, likely indicating this isn't the first time he's made this mistake. In the game, watering plants is an essential chore, which requires the player to "equip" a watering can. The player moves their character up to a plant and simply presses an action button (or key) to perform the watering action. The same action button is used to interact in different ways with other things, animals and people (e.g. to talk to them), so accidentally leaving the watering can equipped while trying to talk to someone can cause the player to "water" them instead. The comic illustrates how easy it is to do this in the game, as well as the comedic value of seeing this happen from the point of view of the player's character. The title text reinforces this humor by indicating that Randall has used the watering can, probably unintentionally, on nearly every person and object in the game. It's amusing to think that he may curse each time he realizes he's still holding the can when he tries to talk to someone. (His use of the word "Dammit" in this comic also calls to mind a brief discussion on the word in 559: No Pun Intended .) The use of the word "virtually" in the title text plays with the word's double meaning. It is used here in the sense of "almost", however when swapping the words "virtually" and "waters", the word assumes its alternate meaning, but the title text still makes sense: Since the game is only a simulation, the player "virtually waters" his plants. Stardew Valley was also mentioned only two weeks prior to this comic in 1790: Sad ; this comic explains why. Interestingly, this comic is drawn in a slightly unusual style for xkcd . Of note is the border around the caption ("Stardew Valley Morning Routine"), the thicker-than-normal penmanship, and the use of drawn borders around the watering sound effects, Cueball's yawn, and the cat's sleeping word balloon. The cat's balloon in particular follows the visual style of the game (in which certain objects and animals may show their current emotional states with word balloons) - more generally, actions that normally occur in the game, such as the yawn and the watering action, appear to be shown in balloons while Cueball's "Dammit!" is written in the style of other xkcd comics. This likely suggests that Cueball's epithet here represents the player (Randall) actually saying this in response to the incorrect action of his character in the game. [Inside a slim frame at the top of the comic there is a caption:] Stardew Valley morning routine [Below this frame there are two rows each consisting of three small panels taking up the same width as the caption panel above:] [Cueball wakes and rises up from his pillow sitting beneath his blanket in his four poster bed with round knobs. He yawns with a hand to his mouth. Above him floats a large sound bubble:] Cueball: Yawn [Cueball walks to the right with a small watering can held in front of him.] [Cueball pours water from the can over the three small plants. A line goes from the water to another bubble:] Water: Splish [Cueball walks back to the left with the watering can.] [Cueball stops with the can right next to a sleeping cat, which has a speech bubble pointing to its head.] Cat: Z [Cueball proceeds to pour water on the cat which immediately jumps up away from him trying to escape as water cascades on it. Again there is a line from the water to a speech bubble, but both the cats angry sound and Cueball's comment is written without bubbles.] Water: Splish Cat: Mrowl!! Cueball: –Dammit.

Box Plot

Box Plot

https://www.xkcd.com/1798

https://www.explainxkcd.com/wiki/index.php/1798:_Box_Plot

[A box plot with three vertical data points is shown. Each point consists of a shaded rectangular box, and a T-shaped whisker on each end.] [Cueball walks in; revealing that the box plot is a physical object which he looks up on.] [Cueball climbs on top of the diagram, holding onto the top whisker of the leftmost data point.] [Cueball, now standing upright on top of the box plot, bends over, grips the whisker of the center data point and starts pumping. The shaded box of the data point bulges. Cueball's movements are accompanied by sounds:] Pump Pump Pump [The box has been inflated so much that it almost touches the left and right data points. Cueball walks away.]

This comic shows three vertical box plots in the first panel, hence the title. In descriptive statistics , a box plot is a convenient way of graphically depicting groups of numerical data through their quartiles . The second quartile is the median and it is not indicated in this comic, as it should be a line through the box (see the definitions of quartiles ). But the top and bottom of the box is the first and third quartile, which splits the lowest/highest 25% off data of from the highest/lowest 75%, respectively. Box plots may also have lines extending vertically from the boxes (whiskers) indicating variability outside the upper and lower quartiles, (that is, the highest and lowest values in the data,) hence the terms box-and-whisker plot. These can be used to indicate the interquartile range , a measure of statistical dispersion . These have been included on the three boxes in the plot. The joke in the comic arises, because it turns out that the box plot is actually three real world objects and Cueball walks into the plot in the second panel, climbs up on the lower first box and on to the highest middle box. When the boxes are depicted in the orientation shown, the boxes can look like they are pumps, where the middle part, the box, can be pumped up. And Cueball does just that in the fourth panel, by pushing the top whisker down and when he leaves in the fifth and last panel, this box stays inflated, with the whisker visibly lower than in the first three panels, although higher than when he pushed it down in the fourth panel. (Inflating things that cannot be inflated was also the joke in 1395: Power Cord . But as opposed to inflating the meaning of data, which many researchers sadly do in the real world, what Beret Guy does in that comic, is strictly supernatural .) It could be said that the "data" in this comic was "inflated" and thus Cueball has been trying to show a smaller interquartile range than there actually is, thus inflating the possible conclusions that could be drawn from the data. The title text refers to how dynamite , an explosive, often used to have detonator boxes (aka. blasting machines ) which also looked similar to the top part of the box (without the lower whisker). These detonators were most commonly used for mining, with long wires leading to the explosives. Modern blasting machines are operated by push buttons and key switches, but the old push-handle design still resonates in the public consciousness today, due to its exposure in classic slapstick cartoon shorts like Looney Tunes , especially often used by Wile E. Coyote against the Road Runner. See this compilation for examples. The title text also refers to so-called dynamite plots . This type of plot used to be very common in scientific publications, but since it hides most details about one's actual data, it is now frowned upon. The recommended alternative is the box plot. The title text thus warns against this kind of data inflation, since sometimes it can go awry and lead to explosions. Randall has often made comics about presenting data as more important that they are, in one way or another, and this comics clearly falls into that category. See for example 882: Significant , 1132: Frequentists vs. Bayesians , 1478: P-Values and 1574: Trouble for Science , and this one for manipulating the way data is presented: 558: 1000 Times . A box plot was also used in 539: Boyfriend , maybe the only other time in xkcd. There are many other types of data carts that have their own subcategories, but not this type. [A box plot with three vertical data points is shown. Each point consists of a shaded rectangular box, and a T-shaped whisker on each end.] [Cueball walks in; revealing that the box plot is a physical object which he looks up on.] [Cueball climbs on top of the diagram, holding onto the top whisker of the leftmost data point.] [Cueball, now standing upright on top of the box plot, bends over, grips the whisker of the center data point and starts pumping. The shaded box of the data point bulges. Cueball's movements are accompanied by sounds:] Pump Pump Pump [The box has been inflated so much that it almost touches the left and right data points. Cueball walks away.]

Bad Map Projection Time Zones

Bad Map Projection: Time Zones

https://www.xkcd.com/1799

https://www.explainxkcd.com/wiki/index.php/1799:_Bad_Map_Projection:_Time_Zones

Bad map projection #79: Time Zones Where each country should be, based on its time zone( s ) [A world map is shown divided and colored by political boundaries. There are many distortions, and especially Russia looks weird. Many countries have their name listed in a gray font and at the bottom below Australia there are two specialties mentioned for time zones which are not divided in full hours. One of these is a footnote used by other countries as well.] [The labels are listed here in order of the "continents" as they come from top left to down right. Similarly within each continent's list the countries which are usually said to belong to a given continent (at least politically or partially, e.g. Greenland and Turkey in Europe) are listed in a similar reading order as accurately as possible.] [North America. (Newfoundland, the most easterly part of Canada, is labeled with a star *):] Canada, *, United States, Mexico, Gua., Hon., Nic., C.R., Pan., Cuba, Haiti, Jam., D.R. [South America:] Colombia, Venezuela, Guyana, F.G., Suriname, Peru, Brazil, Bolivia, Par., Chile, Argentina, Uruguay [Europe. (Russia is as the only country mentioned twice, the other place is over the central part in the Asia section):] Greenland, Iceland, Norway, Sweden, Finland, Ireland, UK, Lithuania, Latvia, Estonia, Bel., Russia, Ger., Pol., Ukraine, France, It., Romania, Portugal, Spain, Bulgaria, Turkey [Africa:] W.S., Tunisia, Morocco, Algeria, Mauritania, Sen., Mali, Niger, Libya, Egypt, Sudan, Gb., Guin., B.F., S.L., Liberia, Côte d'Ivoire, Ghana, Nigeria, Chad, Cam., C.A.R., S.S., Ethiopia, Somalia, E.G., Gabon, R. of Congo, Dem. Rep. of the Congo, Kenya, Angola, Zambia, Tanzania, Namibia, Bots., Zimb., Mozambique, Madagascar, South Africa [Asia. (Russia is the only country mentioned twice, the other label is within the European border. The text written over Bhutan is unreadable in the image and marked with a question mark in this list):] Iraq, Saudi Arabia, Yemen, Iran*, Oman, Russia, Kazakhstan, Mongolia, Turkmenistan, Uzbekistan, Afghanistan*, Taj., Pakistan, India*, Nepal*, ?, China, N.K.*, S.K., Japan, Ban., Bur.*, Laos, Vietnam, Thailand, Philippines [Oceania/Australia. (In Australia there is a star * in the middle of it above the name):] Malaysia, Indonesia, Papua New Guinea, *, Australia, New Zealand [Below Australia there is an arrow pointing to the south coast and below that a footnote for the stars * used above:] UTC+8:45 (One small area) *=Half-hour offset Some countries and territories are missing from the map. Most of these omissions are undoubtedly deliberate, but some are likely mistakes.

This is the second comic in the series of Bad Map Projections and presents Bad map projection #79: Time Zones. It was first with this comic that it became a series. The series began a month earlier with 1784: Bad Map Projection: Liquid Resize (#107). It was followed almost three years later with 2256: Bad Map Projection: South America (#358). This comic shows a map projection in which countries are placed according to the time zones that they fall under. It seems that Randall , being Randall, runs with the idea as he has made yet another map projection that is not only inaccurate, but utterly unusable, though less so than the previous one. The first "Liquid Resize" was #107, while this comic features #79. Since the liquid resize was purely aesthetic, whereas this one at least conveys some meaningful information it makes sense that this projection is ranked higher. Conceptually, the series is a comment on the fact that there is no perfect way to draw a map of the world on a flat piece of paper. Each one will introduce a different type of distortion, and the best projection for a given situation is sometimes very disputed. Randall previously explored 12 different projections in 977: Map Projections , and expressed his disdain for some types he sees as less efficient but whose users feel superior. None of them are really good as any 2D map projection will always distort in a way the spherical reality, and a map projection that is useful for one aspect (like navigation, geographical shapes and masses visualization, etc.) will not be so for all the others. Local maps of smaller areas can be quite accurate, but the idea of both these map projection comics is to map the entire globe on a flat surface. Time zones are based on the way the Sun shines on the Earth, so these time zones, which are based on the sun's position in the sky, would best be divided by roughly longitudinal (North-to-South Pole) lines. However, this is not the case in practice, as the defined time zones tend to have very jagged boundaries, and furthermore some countries use a completely different time than the zones they are in, at least for some parts (see China ). Since Randall knows he cannot fix the boundaries of the time zones, he instead "fixes" the world by making a map appear to match up with the time zone system, as shown in this map , also posted in the trivia . This results in bizarre distortions such as the large, gum-like strands of Greenland (these are the towns of Danmarkshavn (UTC) and Ittoqqortoormiit (UTC-1), which use different time zones to the rest of the island) and three enormous gulfs in Russia (some time zones in Russia are only used in southern areas, leaving two-hour differences between some adjacent areas on the country's northern border). See also this map with a time zone map overlayed the comic . The effect of this map is to "punish" large countries with a single time zone - for instance, China, which uses UTC+8 across the whole country - and countries that share large time zones - for instance, almost all of Europe is packed into the Central European UTC+1 zone - by shrinking these down. Conversely, countries that use multiple time zones without filling them out are stretched out - for example, the Democratic Republic of the Congo (DRC) and Mongolia , as pointed out in the title text - as are slim countries that do not fill out the full width of their time zones but where their neighbors use different timezones so they have to fill the entire width of their time zone. For instance Finland (also mentioned in the title text) and the Baltic countries , who look huge because their western and eastern neighbors do not use the UTC+2 Eastern Europe time, and thus have to fill out the distance between the countries that are pushed to the zones on their east/west borders. Other map projections distort countries this way as well, but based on their actual physical location as opposed to their position on imaginary time zones. The Mercator projection is infamous for distorting Greenland in this way, to the point that it appears to be larger than Africa despite being nowhere near the same size. See the table below for lots more information on the comic, but here are some further details. The map is imperfect for several reasons: Randall attempts to preserve adjacency where possible - for instance, Chad and Sudan are neighbors even though Chad uses West Africa Time (UTC+1) and Sudan uses East Africa Time (UTC+3). Randall draws an extremely thin strand connecting the countries through Central/South Africa Time (UTC+2), even though no part of Chad or Sudan uses this time. Similarly, a thin strand of Kazakhstan and Turkmenistan is shown projecting into the UTC+4 time zone in order to separate Russia and Iran, which do not really share a border. Worst of all is China, which has to have borders to several countries that do not share the single eastern time zone of east China, which the whole China is forced to use. A thin strand, resembling the Yangtze river, is shown passing through time zones that China does not use. This is the most complicated preservation of adjacency shown in the map. There is no mention of daylight saving time - all countries shown are given the base winter time. Depending on the time of year, countries will shift around - around June, many northern hemisphere countries will move east, while some southern hemisphere countries will move east around December. The map doesn't allow for half-hour time zones. (India, for instance, is on UTC+5.5) Instead, countries that use fractional time zones are shifted so they straddle the two time zones, and are then marked with an asterisk (*). This is also true of regions within countries, including the island of Newfoundland in Canada and a section in the center of Australia. The only extra detail mentioned in the map is also for Australia. It is the UTC+8:45 time zone that is used only by 5 roadhouses covering a population of only a few hundred people. There are several errors in the map, see below . This sortable table includes all countries shown in the map, not just those are labeled, as well as the continents and some other regions are mentioned. The countries or continents are mentioned approximately in reading order. If a country is not labeled with full name the abbreviation is in brackets behind the name. If the country is not labeled, labeled wrong or not even shown in the comic, there is a note after the name. Countries labeled with a footnote by an asterisk (*) are shown together with that asterisk at the name. If a country has more than one time zone all are listed. Bad map projection #79: Time Zones Where each country should be, based on its time zone( s ) [A world map is shown divided and colored by political boundaries. There are many distortions, and especially Russia looks weird. Many countries have their name listed in a gray font and at the bottom below Australia there are two specialties mentioned for time zones which are not divided in full hours. One of these is a footnote used by other countries as well.] [The labels are listed here in order of the "continents" as they come from top left to down right. Similarly within each continent's list the countries which are usually said to belong to a given continent (at least politically or partially, e.g. Greenland and Turkey in Europe) are listed in a similar reading order as accurately as possible.] [North America. (Newfoundland, the most easterly part of Canada, is labeled with a star *):] Canada, *, United States, Mexico, Gua., Hon., Nic., C.R., Pan., Cuba, Haiti, Jam., D.R. [South America:] Colombia, Venezuela, Guyana, F.G., Suriname, Peru, Brazil, Bolivia, Par., Chile, Argentina, Uruguay [Europe. (Russia is as the only country mentioned twice, the other place is over the central part in the Asia section):] Greenland, Iceland, Norway, Sweden, Finland, Ireland, UK, Lithuania, Latvia, Estonia, Bel., Russia, Ger., Pol., Ukraine, France, It., Romania, Portugal, Spain, Bulgaria, Turkey [Africa:] W.S., Tunisia, Morocco, Algeria, Mauritania, Sen., Mali, Niger, Libya, Egypt, Sudan, Gb., Guin., B.F., S.L., Liberia, Côte d'Ivoire, Ghana, Nigeria, Chad, Cam., C.A.R., S.S., Ethiopia, Somalia, E.G., Gabon, R. of Congo, Dem. Rep. of the Congo, Kenya, Angola, Zambia, Tanzania, Namibia, Bots., Zimb., Mozambique, Madagascar, South Africa [Asia. (Russia is the only country mentioned twice, the other label is within the European border. The text written over Bhutan is unreadable in the image and marked with a question mark in this list):] Iraq, Saudi Arabia, Yemen, Iran*, Oman, Russia, Kazakhstan, Mongolia, Turkmenistan, Uzbekistan, Afghanistan*, Taj., Pakistan, India*, Nepal*, ?, China, N.K.*, S.K., Japan, Ban., Bur.*, Laos, Vietnam, Thailand, Philippines [Oceania/Australia. (In Australia there is a star * in the middle of it above the name):] Malaysia, Indonesia, Papua New Guinea, *, Australia, New Zealand [Below Australia there is an arrow pointing to the south coast and below that a footnote for the stars * used above:] UTC+8:45 (One small area) *=Half-hour offset Some countries and territories are missing from the map. Most of these omissions are undoubtedly deliberate, but some are likely mistakes.

Chess Notation

Chess Notation

https://www.xkcd.com/1800

https://www.explainxkcd.com/wiki/index.php/1800:_Chess_Notation

[Cueball and White Hat facing each other.] Cueball: I've decided to score all my conversations using chess win-loss notation. White Hat: I don't know or care what that means. Cueball: Fine. White Hat: Fine. [Caption below the frame:] ½–½ The following points are debated: Chess players and critics use certain notations to write down chess games in a very short fashion (for example the Forsyth–Edwards Notation , which is both computer- and human-readable). In addition, chess annotation symbols like ! and !? help to comment certain moves in a similarly short fashion. That way it is possible to print or discuss a chess game (or a chess opening) in a limited space, for example in printed reference manuals. A short synopsis about common chess annotation symbols: !! – brilliant move: Very strong and counter-intuitive move. A sound sacrifice. ! – good move: A surprisingly good move. !? – interesting move: Risky, or worthy of attention and analysis. ?! – dubious move: Designates a move that may be bad, but it is hard to explain why. ? – mistake: Poor move that should not be played. ?? – blunder : Exceptionally bad move, usually designates a move that turns a winning position into a draw, or a draw into a losing position. The score of the "white" player is always given first, followed by the score of the "black" player. Possible notations for the game outcome are: 1-0 – a win (for white) 0-1 – a loss (for white) ½-½ – a draw Because every chess game begins by moving a white piece, the following can be observed: When Cueball ends a conversation with 1-0, A chess game can be won (and lost for the other party) or drawn . It should be noted that draws most commonly occur by agreement , or very rarely by stalemate . A stalemate is a situation where the opponent's king is not in check, but none of the opponent's pieces can be moved in a legal way. In a human conversation, what amounts to a draw, and what amounts to a stalemate? If agreed draws should be allowed (and under which circumstances) is a matter of some discussion among chess players, thus adding another point to Randall's comic. For example, some tournament rules (e.g. the so-called " Sofia Rules ") do not allow a draw to be offered directly - any player has first to announce the intention of drawing to the arbiter (referee), who then decides if the position should be played out further or not. The official chess rules offer some ways the concept of a "draw" could be applied to a human conversation. According to the World Chess Federation (FIDE) rules, a draw can occur: Similarities Differences

Cueball begins a conversation with White Hat with the declaration that he will be scoring his conversations using chess notation (hence the title). White Hat is not interested, so the conversation dies out, with both Cueball and White Hat saying "Fine". And just as promised, Cueball has scored this particular conversation, giving it a ½-½ , as he believes that this is a drawn conversation . The reasons for the draw may be due to agreement (both parties walk away afterwards), a stalemate (the conversation isn't going anywhere), draw by repetition (both players have played the same moves over and over again, and cannot improve their position - probably if "Fine" had been repeated more times), 50-move rule (the conversation has been going on fruitlessly for too long - unlikely here since it is only 4 dialogues long) or something else. There could be some similarities between chess games and conversations . In general, see more under the trivia section. The title text contains the same assertion that Cueball is scoring all his conversations in chess notation, followed by a (??). In chess notation, (??) means the move in question was a very bad, or losing, move - a blunder. Cueball scores this part of the conversation as a blunder, which is understandable as it immediately turned the conversation against him. It can also be considered a losing move not just in the conversation but in general, being a confusing and pointless decision with no apparent gain. If Cueball is treating his conversation itself like a chess game (memorizing openings, using tactics, and evaluating various possible things to say), then he will avoid ever opening a conversation with this statement again. If he was scoring his idea to score his conversations as a blunder, then that itself may yet be another blunder. Either way, quite a ?? indeed!! The (??) may also be interpreted not as chess notation, but as regular interpunction, in which case it would denote a confused reaction by someone who doesn't know what chess notation is (like White Hat in the comic). This makes it a double entendre, covering both the case when either the conversation party or the reader doesn't understand what chess notation is (and thus reacts with confusion to Cueball's announcement), and the case when chess notation is understood, and actually used to comment on the soundness of Cueball's move as being a blunder. [Cueball and White Hat facing each other.] Cueball: I've decided to score all my conversations using chess win-loss notation. White Hat: I don't know or care what that means. Cueball: Fine. White Hat: Fine. [Caption below the frame:] ½–½ The following points are debated: Chess players and critics use certain notations to write down chess games in a very short fashion (for example the Forsyth–Edwards Notation , which is both computer- and human-readable). In addition, chess annotation symbols like ! and !? help to comment certain moves in a similarly short fashion. That way it is possible to print or discuss a chess game (or a chess opening) in a limited space, for example in printed reference manuals. A short synopsis about common chess annotation symbols: !! – brilliant move: Very strong and counter-intuitive move. A sound sacrifice. ! – good move: A surprisingly good move. !? – interesting move: Risky, or worthy of attention and analysis. ?! – dubious move: Designates a move that may be bad, but it is hard to explain why. ? – mistake: Poor move that should not be played. ?? – blunder : Exceptionally bad move, usually designates a move that turns a winning position into a draw, or a draw into a losing position. The score of the "white" player is always given first, followed by the score of the "black" player. Possible notations for the game outcome are: 1-0 – a win (for white) 0-1 – a loss (for white) ½-½ – a draw Because every chess game begins by moving a white piece, the following can be observed: When Cueball ends a conversation with 1-0, A chess game can be won (and lost for the other party) or drawn . It should be noted that draws most commonly occur by agreement , or very rarely by stalemate . A stalemate is a situation where the opponent's king is not in check, but none of the opponent's pieces can be moved in a legal way. In a human conversation, what amounts to a draw, and what amounts to a stalemate? If agreed draws should be allowed (and under which circumstances) is a matter of some discussion among chess players, thus adding another point to Randall's comic. For example, some tournament rules (e.g. the so-called " Sofia Rules ") do not allow a draw to be offered directly - any player has first to announce the intention of drawing to the arbiter (referee), who then decides if the position should be played out further or not. The official chess rules offer some ways the concept of a "draw" could be applied to a human conversation. According to the World Chess Federation (FIDE) rules, a draw can occur: Similarities Differences