Coordinate Precision

Explanation:
This cartoon gives increasingly precise latitude and longitude coordinates for a location on the planet Earth. However, a given pair of coordinates covers a trapezoidal region of land, and thus leaves some ambiguity; therefore, greater precision requires an increasing count of decimal places in your coordinates. This comic uses this information to roughly identify how precise a given coordinate length might be.
The increasing precision of coordinates in this cartoon are similar to the increasing magnification in the short documentary "Powers of 10," which can be found here .  (Also parodied in #271:Powers of One ).
The coordinates at 28.52345°N, 80.68309°W (in decimal degrees form; in geographic coordinate system form using degrees, minutes, and seconds, 28° 31′ 24.4″N, 80° 40′ 59.1″W) are pointing to the Rocket Garden at the Kennedy Space Center in Merritt Island, Florida —specifically, the tip of the Delta rocket.
The sixth entry in the table, with seven digits of precision, includes the caveat that, while your coordinates map to areas small enough on the Earth's surface to indicate pointing to a specific person in a room, "since you didn't include datum information, we can't tell who". This is a reference to the geodetic datum or geodetic system — different ways of dealing with the fact that the Earth is neither perfectly spherical nor perfectly an oblong ellipsoid. The various datums do not make much difference at six digits of precision, but at seven, there is enough skew depending on which system is in use that the person in a room you are referring to with the coordinates is ambiguous. It is unstated, but the remaining lines in the table with ever-greater precision suffer from this same issue and are equally ambiguous without datum information.
The final entry, with seventeen digits of precision, suggests that either the user is referring to individual atoms in the much-larger-scale whole-Earth coordinate system, or (perhaps more likely) has not bothered to format the values from the GPS module for viewing in the software UI in any way whatsoever, resulting in a value that is meaninglessly precise because the measurement wasn't that accurate to begin with. Even if the value is accurate, locating individual atoms by coordinates is not actually useful in most cases, and the motions of multiple systems within our physical world (continental drift, subtle vibrations, Brownian motion , etc.) would render the precise value obsolete rather quickly.
For the decimal places past the 5th on the latitude, the digits given are actually the first part of the decimal expansion of the constant e (2.7182818284), while for the decimal places past the 5th on the longitude, the digits given are part of the decimal expansion of the constant π (3.14159265358) starting with the second digit (4).
The title text references how at sufficiently small distances, our understanding of reality itself begins to break down. Smaller than the Planck length , which is more than a quintillion times smaller than the diameter of a proton, the ideals of Euclidean geometry no longer apply and space itself may be composed of a quantum foam where the very geometry of spacetime itself fluctuates, meaning coordinate systems based on an assumption that space doesn't change would no longer work. String theory, on the other hand, assumes that at a short enough distance the world is composed of ten space dimensions, which precludes the use of a two-dimensional coordinate system (not that our “normal” three dimensions don't do so in themselves).
The actual number of longitude digits needed to identify a point to a particular precision depends on its latitude. Near the poles, you need fewer longitude digits than at the equator – starting with one digit fewer at around lat. 85°, past all constantly inhabited human settlements, and with two digits fewer at lat. 89.5°, inaccessible to anyone but polar researchers and the occasional guided tour. The number of latitude digits for some particular accuracy stays essentially the same everywhere.
*Since the Earth is not exactly spherical, the actual length of one degree of latitude varies between 110.574 km (68.707 mi) at the equator and 111.694 km (69.403 mi) at the poles, while one degree of longitude is 111.320 km (69.171 mi) at the equator, 55.800 km (34.673 mi) at lat. 60°, and 0 km (0 mi) at the poles.
[Single panel containing a table with two columns for "Lat/Lon Precision" and "Meaning" and a caption above the table.] Caption: What The Number of Digits in Your Coordinates Means
[Row 1] Lat/Lon: 28°N, 80°W Meaning: You're probably doing something space-related
[Row 2] Lat/Lon: 28.5°N, 80.6°W Meaning: You're pointing out a specific city
[Row 3] Lat/Lon: 28.52°N, 80.68°W Meaning: You're pointing out a neighborhood
[Row 4] Lat/Lon: 28.523°N, 80.683°W Meaning: You're pointing out a specific suburban cul-de-sac
[Row 5] Lat/Lon: 28.5234°N, 80.6830°W Meaning: You're pointing to a particular corner of a house
[Row 6] Lat/Lon: 28.52345°N, 80.68309°W Meaning: You're pointing to a specific person in a room, but since you didn't include datum information, we can't tell who
[Row 7] Lat/Lon: 28.5234571°N, 80.6830941°W Meaning: You're pointing to Waldo on a page
[Row 8] Lat/Lon: 28.523457182°N, 80.683094159°W Meaning: "Hey, check out this specific sand grain!"
[Row 9] Lat/Lon: 28.523457182818284°N, 80.683094159265358°W Meaning: Either you're handing out raw floating point variables, or you've built a database to track individual atoms. In either case, please stop.


Shadow Biosphere

Explanation:
A shadow biosphere is a hypothetical microbial biosphere of Earth that uses radically different biochemical and molecular processes than currently known life. Although life on Earth is relatively well-studied, the shadow biosphere may still remain unnoticed because the exploration of the microbial world targets primarily the biochemistry of the macro-organisms.
Because organisms based on RNA would not have ribosomes, which are usually used to detect living microorganisms, they would be difficult to find in normal circumstances.
The comic suggests that this hypothetical biosphere exists, and its study is funded by "shadow biotech" corporations. The field would be called "shadow biology", so people that study it would be "shadow biologists". However, this is reinterpreted to mean "shadow" biologist, meaning that anyone that studies it becomes undetectable. A "shadowy" figure, presumably a shadow biologist, is telling this to Megan and Cueball , but they are not shadow biologists and can't hear him.
The title text references desert varnish , an orange-yellow to black coating found on exposed rock surfaces in arid environments, which has been suggested as a potential candidate for a shadow biosphere. Unless a building was made with already-varnished rocks, it would be impractical to cover a building in desert varnish (it forms naturally on rocks over thousands of years). Ignoring its impracticality, the joke is that if a building were covered in desert varnish, it would supposedly be invisible to biologists who don't study the shadow biosphere.
[Cueball and Megan are standing facing each other. A shadowy figure is behind Megan.] Shadowy figure: These days most of our funding comes in from the shadow biotech industry. Megan: Did you hear something? Cueball: I think it's the wind.
[Caption below the panel:] The shadow biosphere exists, but if you study it, you become a shadow biologist.


Lunar Cycles

Explanation:
This comic shows a mixture of real, scientific lunar cycles and cycles that are comedic or fictional in nature.
The light gray "phase × distance" plot does not correspond to the product of periods given for phase and distance, which look like this instead. A harvest moon is the traditional name for the full moon closest to the autumnal equinox, but there is nothing astronomically significant about it. A supermoon is a full or new moon when the Moon is closest to the Earth, resulting in a slightly larger-than-usual apparent size. A full supermoon is roughly 14% larger in diameter than when the Moon is furthest away. See also 1394: Superm*n . A blue moon was originally a description of the very rare occurrence of atmospheric conditions that gave the Moon a bluish tinge, hence the expression "once in a blue moon" for something that happens only rarely.  However, the actual blue-hued appearance of the moon is so rare that it the phrase "blue moon" has been reinterpreted as referring to a merely uncommon event:  the occurrence of two full moons in a single calendar month. That kind of "blue moon" naturally does not look any different from a regular full moon. A blood moon refers to the moon during a lunar eclipse. While the popularity of skinny jeans ( slim-fit pants ) does change over time, the idea that this is connected to a lunar cycle is also a joke. The Golden Age of Television is said to have occurred in the 1940s and 50s, and the 2000s. Pork moon cakes have been prepared in the rural areas west of Shanghai since more than a thousand years ago, for the Chinese Mid-Autumn Festival . "The Vampire of the Dire Moon " is a recently introduced, uncommon card from the Magic: The Gathering card game. Astrology is a pseudoscience which claims that the positions of the celestial bodies can be used to predict human affairs. The chart jokingly suggests that astrology actually does work, but only within a very specific two-week timeframe. Finally, while the idea of a total eclipse of the sea seems absurd, an eclipse was famously used to explain the migration of maritime animals : biologists were beginning to unravel the mystery of this ‘false bottom’–a layer in the ocean that looks the the sea floor on the sounder but isn’t–which covered much of the ocean. This false bottom rises in up at night and sinks down during the day. This rising and falling is in fact caused by the largest migration of animal on Earth–everything from fish, shrimp and jellyfish, moving hundreds of meters in unison up and down each day.... the moon moved into its place in front of the sun, daylight rapidly faded, and the scientists solved the migration mystery: the deep layer of animals began to rise. Bioluminescent creatures started to shine, and nocturnal creatures started a frantic upward thrust. As the world grew darker, they swam upward nearly 80 meters. But this frantic migration didn’t last long. As the moon receded and the sun revealed itself, the massive animal layer did an about-face, scrambling back into the safety of the darkness. (Backus, Clark, and Wing (1965) "Behaviour of certain marine organisms during the solar eclipse of July 20, 1963" Nature 4975: 989-91.)
The Antikythera mechanism mentioned in the title text is an ancient Greek machine, rediscovered in 1901, designed to calculate astronomical positions. The title text jokes that there is a set of gears on said mechanism that is used to predict the popularity of "skinny jeans" and "low-rise waists."  Since it was likely created in the 1st or 2nd century B.C., it is impossible for the creators to have had any knowledge of skinny jeans or low-rise waists - both are modern-day clothing fashions [ citation needed ] .
Understanding lunar cycles
Nodal precession [A diagram showing a broad cosine-like wave with wavelength labelled as 18.6 years. To the right are two diagrams showing an orbital cycle moving in and out of plane.]
Apsidal precession [A diagram similar to the one above but with a slightly shorter wavelength, labelled as 8.9 years. To the right are two diagrams showing an elliptical orbit around a planet and the same orbit rotated.]
Phase [A diagram similar to those above with a shorter wavelength, labelled as 29.5 days. To the right is a diagram showing four phases of the moon: New, Waxing crescent, Waxinf gibbos, Full.]
Distance [A diagram similar to those above with a shorter wavelength, labelled as 27.5 days. To the right is a diagram showing the distance of the moon from the Earth over time, with distances marked by arrows.]
Earth-Moon relative size [A wave with long wavelength with an arrow pointing to the minimum labelled 'Earth bigger' and an arrow pointing to the maximum labelled 'Moon bigger'. To the right are two diagrams of the moon and Earth, one showing the Earth bigger than the Moon and the other showing the Moon bigger than the Earth.]
Lunar shape [A wave with long wavelength with an arrow pointing to the minimum labelled 'Circle' and an arrow pointing to the maximum labelled 'Square'. To the right is a diagram showing a circle, a circle transforming into a square with outward arrows at each corner and a square transforming into a circle with inward arrows.]
Lunar mood [A wave with long wavelength with an arrow pointing to the minimum labelled 'Bad' and an arrow pointing to the maximum labelled 'Good'. To the right are four emojis: :), :|, :(, :|]
[A superimposed graph of all the above waves. Different points on the graph are labelled: Harvest moon, Supermoon, Blue moon, Skinny Jeans popular, Super blood moon, Golden age of TV, Dire moon, Pork moon, Two week window in which astrology works, Total eclipse of the sea.]


Trained a Neural Net

Explanation:
An artificial neural network , also known as a neural net, is a computing system inspired by a human brain, which "learns" by considering lots and lots of examples to develop patterns. For example, these are used in image recognition - by analyzing thousands or millions of examples, the system is able to identify particular objects. Neural networks typically function with no prior knowledge, and are "trained" by feeding in examples of the thing that they are told to analyze.
Here, Cueball is telling White Hat how he trained a neural net to sort photos into categories. The joke in the comic, is the engineering tip from the caption. It states that since a human brain is already a neural network, albeit a biological one instead of an artificial one, then by teaching oneself (or others) to do a task, you are de facto training a neural network to do so. So instead of designing and training an artificial neural net that could do this task, all Cueball did was manually sort the photos into categories (although he could then use those sorted images to train an artificial neural network). This is the first time such a tip has been used, but engineering tip just continues the tips trend that Protip began long ago.
It is not advisable to say this in real life, because you might then be expected to use your already-trained neural net to do a similar task (or redo the same task) with much greater speed, thus ruining the façade.  However, presenting work done by humans as work done by machines has been done in real life, perhaps starting with The Turk in 1770 and continuing into the present day by various AI-themed startups.  For example, Engineer.ai described itself as using "natural language processing and decision trees" to automate app development, but was actually employing humans .
The title text is a continuation of this joke, as instead of designing and training two artificial neural nets named "Emily" and "Kevin", all he has done is train two people with those names to manually respond to support tickets. Again, doing this in real life is not advisable, as people are offended when they are referred to by programmers as deterministic automata with no free will. [ citation needed ]
Neural networks have been trained to perform other tasks that are routine for humans, but formerly more difficult for computers, such as driving cars, playing games like chess, go, and Jeopardy!, and communication skills like extracting phonological information from speech as per Figure 1 here . In 1897: Self Driving , Randall suggested that crowdsourced applications like ReCAPTCHA, that have been used to train neural nets to recognize objects necessary for safe driving in photographs, may also be used for Wizard of Oz experiments . An example of such a Wizard of Oz experiment for phonological training as a form of peer learning has been explored, and related work is occurring on automating vocational training.
The extent to which computer neural nets are analogous to human neurobiology is a topic which fascinates the scientist and layperson alike. While there is no fully universal consensus on the matter, at least one apparently longstanding theoretical paradigm has received attention recently.
[White Hat is looking at a smartphone in his hand, while he talks to Cueball, who lifts a hand palm up towards White Hat.] White Hat: Oh, hey, you organized our photo archive! Cueball: Yeah, I trained a neural net to sort the unlabeled photos into categories. White Hat: Whoa! Nice work!
[Caption below the panel:] Engineering Tip: When you do a task by hand, you can technically say you trained a neural net to do it.


First News Memory

Explanation:
Seven xkcd characters are discussing their "first news memory", their first memory of an event that was reported by the news media. A person's "first news memory" can vary based on their age, the region where they grew up, and how in touch with the news they are.
The following is a breakdown of the memories given by the characters, in typical xkcd fashion:
Four people are standing in-frame: Ponytail , Cueball , Megan , and Hairy .
Ponytail gets the ball rolling by posing the question. Cueball recalls the election coverage from the year 1988. As Randall lives in the US, this is probably the 1988 US presidential election in which George H. W. Bush defeated Michael Dukakis. Megan recalls the removal of the Berlin wall , which began in 1989.
The view pans right to show Megan, Hairy, White Hat , and Black Hat standing around.
Hairy recalls the Challenger explosion , which occurred in 1986. Many schools allowed teachers to bring a television to the classroom to show their students the launch, sadly unaware of the impending disaster the children would witness. However, Hairy remembers watching the footage in 1995, so Hairy's teacher was knowingly showing the students recorded footage of a disaster. Presumably, knowingly showing a number of young schoolchildren a traumatizing event led to the teacher's dismissal.
The view pans right to show Hairy, White Hat, Black Hat, and Hairbun standing around.
White Hat says that his first news memory was about the 2016 election (presumably the 2016 US presidential election ), which is only three years prior to the publication date of this comic. As he is in his thirties, this implies that he spent most of his life not paying attention to the news.
The view pans right, leaving just White Hat, Black Hat, and Hairbun in-frame.
Black Hat 's first sentence is normal in the context of the question, albeit making him older than the others. Given only the sentence 'we landed on the moon,' the 'we' is inferred to be 'the United States of America' or 'the human race.' The first moon landing occurred on July 20, 1969.
However, Black Hat goes on to say that 'my second memory is my mom telling us we were moving to Earth instead, to blend in with the humans.' This gives a completely different meaning to his first memory, as it is now implied that Black Hat is a humanoid alien who moved to the Moon, but whose mother then decided to move to Earth. Whether any news coverage resulted is unclear. Hairbun then remarks that this revelation explains Black Hat's odd (and usually disruptive) behavior. It is unclear whether Black Hat is telling the truth, but knowing Black Hat, and considering the fact that this would be unlikely to receive news coverage, he is likely intentionally trying to unnerve others.  Another possibility is that Black Hat was the youthful victim of a prank by his own mother, with Hairbun's comment implying that such an upbringing accounts for the trollish aspects of Black Hat's character in the present day.
The title text gives the claim that flashbulb memories of big events can be unreliable. Randall (or another character in the comic, possibly Hairbun) denies this claim, claiming to remember watching on CNN as the Challenger spacecraft crashed into the Berlin Wall. This is an inaccurate memory of these two events, as the Challenger explosion occurred in 1986 over the Atlantic Ocean, just east of Cape Canaveral, Florida, and did not occur near the Berlin Wall (in Berlin, Germany). Also, the Berlin Wall was intentionally demolished starting in 1989; it was not damaged by a space shuttle. It is possible that this memory also conflates those events with those of the September 11 attacks since the latter did involve three winged craft crashing into and destroying landmark structures.
[Ponytail, Cueball, Megan, Hairy, White Hat, Black Hat and Hairbun are all at a party, discussing their earliest news memories.]
[Panel with Ponytail, Cueball, Megan, and Hairy] Ponytail: What's your first news memory? Cueball: I always like this question! Mine was the 1988 election. Megan: Berlin wall for me. You?
[Frame-less panel with Megan, Hairy, White Hat, and Black Hat] Hairy: Watching the Challenger launch in class. We were so excited; everyone was horrified when it blew up. Hairy: It was 1995. Hairy: Our teacher got fired soon after.
[Panel with Hairy, White Hat, Black Hat, and Hairbun] White Hat: Mine's the 2016 election. Hairbun: ...aren't you in your 30's? White Hat: Look, we're not all great about keeping up with the news, OK?
[Panel with White Hat, Black Hat, and Hairbun] Black Hat: My first memory is when we landed on the moon. Black Hat: My second memory is my mom telling us we were moving to Earth instead, to blend in with the humans. Hairbun: This explains a lot.


Flag Interpretation

Explanation:
In many countries including the United States (whose flag is depicted in the comic), it is customary to lower the flag to half staff when important public figures die. This is normally done by raising the flag to full height, then immediately "lowering" it to half height. In the US, regulations regarding flying the flag at half staff specify the length of time for the flag to be flown at half staff, and are based on the importance of the person who has died. There are no regulations where the flag would be flown at any height other than full height or half staff, and there are no regulations where multiple flags would be flown.
The definition of half-staff, or half-mast, differs between countries and does not necessarily imply flying the flag at half the height of the pole or mast. For example, in the USA the flag is usually flown at half the height of the pole, whereas UK practice is to leave space for an 'invisible flag' above the flown flag, which may mean flying the flag near the top of the pole depending on its height. These differing practices contribute to confusion and ambiguity concerning the flag height, which is exploited in the comic.
Randall, as usual, makes a humorous list of fictional additional traditions.
The title text is a reference to The Persistence of Memory and other paintings and sculptures by Salvador Dalí which include watches and other objects that are melting.
[8 panels in 2 rows, 4 panels per row - each panel shows a flagpole in a different state of flying flag(s) with a caption at the bottom of the panel below the flagpole.] [The US flag at half mast.] Caption: Someone important died [The same flag at three-quarter mast.] Caption: Someone died but we're not sure how we feel about them [The flag at the base of the mast.] Caption: Everyone important died [Two identical flags at full mast.] Caption: Someone important was successfully cloned [Two identical flags at half mast.] Caption: An important person died battling their evil clone [An upside-down flag at half mast.] Caption: Nobody has died for weeks and that seems good but statistically it's very alarming. [A normal-sized flag at half mast and five tiny flags at full mast.] Caption: Someone diverted a trolley to save five people by killing one important person [A flagpole with no flag.] Caption: The person who knows where the flag is stored at night died.


How Hacking Works

Explanation:
In similar spirit to 538: Security , this comic deals with how many people perceive hacking and security best practices, and how it differs from the actual reality. Specifically, the comic points out the flaw in the argument of some security-minded people that writing passwords down on a sheet of paper is a massive operational security vulnerability, not accounting for the threat model of the general public: reused passwords being leaked from seemingly benign places.
The first panel shows a group of masked men, who have apparently flown to the US from a different country and broken into someone's house. They find a book labeled "Passwords" that contains all the passwords of their target, and one reports this using a walkie-talkie , while another remarks that the target is a fool for writing down their passwords. While it is true that storing passwords on paper is generally a bad idea, one has to keep in mind the alternatives—password reuse or unencrypted password documents on a computer—that non-technical people might otherwise engage in. These are far easier to exploit for a casual attacker that goes for quantity over quality.  In addition, given the larger group of potential attackers are the remote attackers, storing passwords on a piece of paper, while horrible for security from a local "in person" attacker, is actually pretty effective against a remote attacker being able to gather up your passwords.
The second panel goes into detail how such an attack is usually executed: First, a database containing usernames/emails and associated passwords or insufficiently salted password hashes is stolen from an improperly secured website. Randall's example uses a fictional breach of a small forum dedicated to the band Smash Mouth , but even large companies are not immune to leaks. Assuming the passwords were not hashed, the crooks then go on and automatically try to log in to a popular payment service, Venmo , with the harvested credentials. Even though the success rate might be just fractions of a percent, due to the scale and cheapness of the attack (which can be automated, requiring no sustained effort from the crooks), it is likely still profitable. Such an attack has previously been discussed in 792: Password Reuse .
Although writing passwords on paper can allow users to create unique complex passwords without being limited by human memory, and therefore protect themselves from these sorts of mass-breach attacks, their passwords are now more vulnerable to insider attacks by e.g. family members, close friends, or co-workers.
The way recommended by most security experts to prevent these kinds of attacks is to use a password manager - a secure application that stores all of your passwords in an encrypted vault that only you can access. This way, you only need to remember one password - the master password to your vault - and all of your other passwords can be as long, different, and random as you like. This means that even if a crook manages to get one of your passwords, they won't be able to use it to access any other sites, and so the attack shown in the comic would fail.  Websites can also support two-factor authentication , where the user must supply a randomly changing code from a second device, such as a cell phone application or standalone keyfob, to log in.
The title text is referring to Smash Mouth's song " All Star ," where the first line of the lyrics is "Somebody once told me the world is gonna roll me."  The singer subsequently admits that he is not "the sharpest tool in the shed," which would be consistent with re-using simple passwords across multiple accounts (including financial accounts).
[Two panels with a caption below each panel:]
[Three masked characters standing near a desk with a computer inside a home. One of the masked characters is holding a notebook.] Masked Character 1 [holding a walkie-talkie]: Control, we have flown to the USA and breached the target's house. Masked Character 2: They wrote all their passwords in a book labeled "Passwords"! Masked Character 3: The fool!
[Caption below the panel:] How people think hacking works
[Two Cueball-like characters, each sitting on opposite sides of a single desk with laptops in front of them] Cueball 1: Hey look, someone leaked the emails and passwords from the Smash Mouth message boards. Cueball 2: Cool, let's try them all on Venmo.
[Caption below the panel:] How it actually works


Gastroenterology

Explanation:
Gastroenterology is the study of the normal function and diseases of the digestive system: esophagus, stomach, small intestine, colon and rectum, pancreas, gallbladder, bile ducts and liver.
Antibiotics are substances that kill bacteria. They are effective at treating bacterial infections, including in the gut; unfortunately, they can also kill the normal gut bacteria. Probiotics are harmless or helpful bacteria which are sometimes used to replace the bacteria killed by an antibiotic. This reduces chances of re-infection by pathogens, and allows the natural gut microbiome to recover more effectively; comic 1471 was about the same theme. Probiotics are included in many foods, such as yogurt, as well as supplements, and are marketed as having health benefits.
The comic plays on the names probiotic and antibiotic.  When matter and antimatter are mixed, they annihilate each-other, rapidly releasing energy (an explosion).
This comic imagines a similar process when probiotics and antibiotics are mixed: Ponytail and a nurse runs into a room, with someone chasing after them, leading the nurse to exclaim that “they’re right behind us.” Ponytail mixes the probiotics and antibiotics, and throws the jar like a grenade, before continuing to run with the nurse. The reaction between the probiotics and antibiotics causes the jar to explode, presumably killing the pursuer. In reality, antibiotics and probiotics are often used simultaneously during treatment, but they are taken so that they do not mix (taken at different times or by different methods). Mixing them as in the comic, would just cause the antibiotic to kill the probiotic bacteria. Explosive reactions between antibiotics and probiotics are highly unlikely. [ citation needed ]
Matter and antimatter would react pretty much instantly upon mixing, not a short time later, as in the comic.  (Also, one could not keep antimatter in a normal jar, or pour it in an atmosphere).  The reaction shown is similar to the reaction between a strong acid and a strong base, which could cause an explosion after a short delay if kept in a tightly sealed container like a water bottle, as in the explosion here.
In the last panel, Ponytail is giving a more mundane summary of what gastroenterology is like (lots of paperwork). This is similar to Indiana Jones saying that archaeology is boring. The explosion sequence might be:
In the title text, Ponytail adds that her work makes her aware of a child coughing as the server was bringing food at the restaurant table, exposing the food to possible germs that could cause a gastrointestinal infection.
[The first five panels appear in a single row.] [Ponytail, wearing a lab coat, and a guy wearing a scrubs hat rush in from the right side of the panel. Ponytail is holding a water bottle. There is a desk on the left of the panel with two jars.] Hat guy: Hurry, they're right behind us!
[Zoom in on Ponytail, behind the desk, pouring the two smaller jars into the water bottle.] An arrow points to the left jar: Probiotic An arrow points to the right jar: Antibiotic
[A borderless panel. Zoom out on Ponytail shaking the water bottle to mix the two substances.] Shake Shake Shake
[Ponytail throws the water bottle toward the right side of the panel, at something off-screen.]
[Hat guy and Ponytail run toward the left side of the panel, as the water bottle explodes.] BOOM
[The last panel is the only panel in its row, appearing at the far right end of the row and slightly narrower than the fifth panel above it.] [Megan and Ponytail sitting at a table, facing each other, having a meal.] Megan: So what's gastroenterology like? Ponytail: Pretty boring. Lotta paperwork.


Expiration Date High Score

Explanation:
Randall is introducing the rules of the game Expiration Date High Score hence the title.
If you find an item which you purchased, but is now past its expiration date , you get a score which is what percent of your lifetime elapsed between when the item expired and when you found it.
Megan , looking in a cupboard, find a can of beans that expired in 2010 (9 years ago), and that gives her a score of 24.3. Megan's age is thus revealed to be 37, found by substituting 2019 and 2010 into the formula 100*(2019-2010)/<age> = 24.3 and solving for the age. This is consistent with 630: Time Travel , in which Megan's date of birth is given as 1983.
Cueball then remarks that she will never beat her mom's jar of pickles that was from 1978. Megan then wonders if there are more cans (from 2010 or before) in the cupboard, and asks Cueball to remind her to not look any further until 2030. At that time the can would have been 20 years old and she would be 48, giving such a can a score of 100*(2030-2010)/48 = 41.6. That would thus beat her mom's high score.
If her mom's jar had expired in 1978 (not clear from the text), and for instance was found last year in 2018, then the formula for the mother's score would be 100*(2018-1978)/<Mom's age>. And this should then not be more than 41, thus revealing the mother age to be around 100 years old today (98 last year). Of course the jar could have had an expiration day some years later, or have been found earlier. Otherwise Megan's mom would have been above 60 when giving birth to Megan. Of course Megan could also just take this extra long wait in case the next can is not from 2010 but only 2013 etc.
Cueball's final remark is that this is a terrible competition, the worst ever. Because keeping food that can spoil could potentially be dangerous, if not so, at least disgusting when finally trying to get rid of it later.
Many perishable items, such as food, cosmetics, medications, batteries, or condoms, have expiration dates, or sometimes best by dates. The only other rule is, that it has to be something you have purchased yourself, so that heritages or stuff that was left in the basement when one moved in, does not count.  A score of 100 or higher would indicate the item expired when you were born or before you were born, meaning it was already expired when you purchased it.
The joke is, that owning expired items without noticing for a long time, is here getting you a high score, while in reality it is not considered favorable to have food that has expired long time ago. [ citation needed ]
The other joke is both the items in the comic (a can of beans and a jar of pickles) do not go bad with time but in fact remain edible indefinitely (as long as the jar/can is not opened and is undamaged.)
Food going bad, in the sense that it will make you sick if you eat it, is most often caused by harmful bacteria growing in the food.  Less often caused by fungi or yeast growing in the food and creating a poisonous substance, like methanol (wood alcohol.)  The process of canning food involves boiling it to kill all possible pathogens, then sealing it in a can/jar while the food is still hot, with no air bubble.  As long as this process is done correctly, the jar lid will have an airtight seal, so as long as the can is not punctured, or does not have a hole become rusted through, no bacteria/virus/yeast/fungi can get in and the food cannot spoil.  Some food may discolor over time in the jar/can, or the texture may change, but it cannot go bad in a way that makes it unsafe to eat.
Megan's mom could not have a jar of pickles with a 1978 expiration date because in 1978 jars and cans of food did not have expiration dates. Since then many countries introduced laws and regulations requiring companies to put expiration dates on perishable goods. In some instances this can have the negative effect of people throwing out good food by blindly following the suggested expiration date. This behavior can incentivize companies to adjust the expiration date, or put expiration dates on non-perishable goods, so that people will re-buy the products sooner.
The title text continues the conversation from the comic. Cueball remarks that they moved since 2010... Thus the beans were apparently bought while living in a different home, meaning they were moved along with their other belongings. This is somewhat unusual as many people take moving as an opportunity to go through their old stuff and get rid of things they no longer need. Since the rules clearly states that you have to have bought it yourself, it could not have been in the house when they moved in, they had to have brought it along (unless they later bought something that was already expired). But given Megan's final answer that "some of us were just born to be champions" indicates that she did bring it along, anticipating this game, and thus given her self a great score. And as is clear she is willing to wait 11 years to try to beat her mom's score.
It is not clear why they are keeping items for long periods of time in order to win.  An easier way to win this game would be to buy food that is already expired.  One could obtain a score of 100 simply by buying something that expired when one was born, and finding it the next day.
[Title up in the panel:]
What's the most expired item you've found in your house?
Calculate your Expiration Date High Score (must be something you purchased)
[Equation in a circle:]
Score = (year you found item) minus (year item expired) divided by (your age when you found it), multiplied by 100
[Megan and Cueball talking in a kitchen, with Megan holding a can.]
Megan: These beans expired in 2010! That's... let's see... 24.3! New personal best! Cueball: You're never going to beat your mom's jar of pickles from 1978. Megan: Maybe there are more cans in there. Remind me not to look until 2030. Cueball: This is the worst competition.
The formula suggests Megans age to be 37, if this comic plays in 2019, when it was released. That puts her birth year to either 1982 or 1981 (depending on whether this plays before or after her birthday in 2019). This is in slight contrast to 630: Time Travel , which implies her birth year to be 1983.


NWS Warnings

Explanation:
The National Weather Service (NWS) is a United States federal agency that is tasked with issuing national weather forecasts and extreme weather alerts .
This comic portrays the NWS as a person that needs breaks, which is absurd, as it is an important service and would probably always have staff active, even on holidays. For example, the NWS continued to work during federal government shutdowns , as it was considered an essential service for the protection of life and property. Even if one of the NWS's 122 local weather offices were to be incapacitated, contingency plans are in place to ensure that nearby offices act as emergency cover; as happened in March 2019 with flooding in Nebraska forcing the NWS office in Valley to evacuate.
Regardless, in this comic the NWS has decided to take a break, and so has opted to issue every extreme weather alert possible for the entire contiguous portion of the United States (including DC, but not Alaska or Hawaii) to make sure no one is caught by surprise by extreme weather, since the NWS will not be able to issue warnings. As the NWS could not be sure which areas will need to get warned of severe incidents, the NWS has decided to issue warning polygons that cover the entire United States (ostensibly except Alaska and Hawaii). A layer of humor is that this would necessitate warnings where they would be highly unlikely to occur in real life; examples include issuing blizzard warnings for Florida, where any amount of snow is rare, and tsunami warnings for areas very far from any ocean coastline.
Each of the text warnings within the map are coloured, which matches the NWS color coding used for a given warning event.
The title text mentions how some of the warnings that have been issued require action to get to safety that contradicts the other warnings, for example, an evacuation warning and a shelter in place order, since doing one would mean failing to do the other. This confusing scenario would likely prompt many concerned citizens to call emergency services for clarification, but the 911 outage alert would advise against this, adding another layer to the absurdity of the occurrence of the NWS taking a break.
This comic was likely inspired by the heat wave that impacted two-thirds of the US for more than a week.
NWS and tornado warnings was later mentioned in the title text of 2219: Earthquake Early Warnings .
Assumptions about text outside of the frame are given in square brackets. This page from the NWS lists all the warnings and colors, including all the hex codes for them which we stole referenced.
[Heading on top of frame:]
Alert: Everyone Just Keep An Eye Out In General
[A map of the 48 contiguous states of the United States, surrounded by several warning polygons that cover most or all of the area, along with parts of neighboring countries or the sea.]
[The following warning headers are printed in different colors around the map of the United States, some of which are cut off by the frame. Assumptions about text outside of the frame are given in square brackets.]
Gale Warning, Tornado Warning, Flash Flood Warning, Air Quality [Alert] Frost Advisory, Severe Thunderstorm Warning, Dense Fog Advisory [Hurricane Force W]ind Watch, Tropical Storm Warning, Ice Stor[m Warning] [Extreme Cold] Warning, Heat A[dvisory] [Flood] Advisory, Snow [Squall Warning] [Storm Surge] Warning, Brisk W[ind Advisory] [Lake Effect Snow] Watch, Coastal Fl[ood Advisory] Dense Smo[ke Advisory] [Severe Weather Sta]tement, Gale War[ning] [Lakeshore Flood] Advisory, Wind Chill Ad[visory] [Extreme] Cold Warning, Blizzard Warn[ing] Hurricane Warning, Extreme Fire [Danger] [Freezing Fog Adv]isory, Tsunami Warning, Avalanche W[arning] [Ice S]torm Warning, Frost Advisory, Fire Warning, Volcano Warn[ing] Ashfall Advisory, Red Flag Warning, Radiological Hazard Warning
[Text below frame:]
When the National Weather Service needs to take a day off, they just issue warnings for everything so no one is caught by surprise.


Spreadsheets

Explanation:
Cueball is doing some task on his computer, with an angel and devil on either side of him , trying to influence his work. The angel is telling him to do things the "right" way, while the devil is telling him to do his work using a spreadsheet , which is considered by professional software engineers to be a shortcut or a hack.
Spreadsheets provide an array of cells, which can contain information or instructions.  Spreadsheets are a common end-user development tool, allowing non-developers to easily create code.  However they can be hard to maintain, thus they are often mocked by developers as a wrong approach to programming. Although it is not clear from the cartoon that this is meant, the "right" alternative to using a spreadsheet for some tasks may involve a database or a more general programming language.
The punch line comes when the angel becomes so intrigued by the spreadsheet functions, Google Sheets in particular, that it gives up trying to dissuade Cueball, and asks for more information from the devil.
In the title text, Randall mentions a time when he created a calendar grid in Google Sheets using a list of dates. This is described as being done in a "single-cell formula", and taking a long time to run. This shows the power and complexity of spreadsheets.  The procedure taking a long time to run, and freezing up the computer for 15 seconds every time it ran, was probably not what Randall's brother had in mind when he requested help.  His brother learned he might need to be wary about what he gets back when asking Randall for assistance.
All functions mentioned in this comic can be found in Google Sheets , but functions similar to some of them can be found in most modern spreadsheet applications.
REGEXREPLACE (text, regular_expression, replacement) ⇒ Replaces part of a text string with a different text string using regular expressions .
ARRAYFORMULA (array_formula) ⇒  Enables the display of values returned from an array formula into multiple rows and/or columns and the use of non-array functions with arrays.
QUERY (data, query, [headers]) ⇒  Runs a Google Visualization API Query Language query across data.
IMPORTHTML (url, query, index) ⇒  Imports data from a table or list within an HTML page.
SEQUENCE (rows, columns, start, step) ⇒  Returns an array of sequential numbers, such as 1, 2, 3, 4.
REGEXMATCH (text, regular_expression) ⇒  Whether a piece of text matches a regular expression.
[Cueball is at his computer. In the air on either side of him are an angel version of Cueball, with a halo and wings, and a devil version of Cueball, with horns and a pitchfork.]
[The angel's dialogue appears in regular print, while the devil's dialogue appears in white print in black speech balloons.]
Angel: Don't use a spreadsheet! Do it right . Devil: But a spreadsheet would be so easy . Angel: In the long run you'll regret it!
[Closeup on Cueball, the angel, and the devil.]
Angel: Take the time to write real code. Devil: Just paste the data! Tinker until it works! Devil: Build a labyrinth of REGEXREPLACE() and ARRAYFORMULA()! Devil: Feel the power!
[Closeup on the devil.]
Angel (off-panel): Fight the temptation! Devil: Ever tried QUERY() in Google Sheets? It lets you treat a block of cells like a database and run SQL queries on them.
[Another shot of Cueball at his computer with the angel and devil at either side.]
Angel: Don't listen to-- Angel: ... wait, really? Devil: Yes, and let me tell you about IMPORTHTML() ... Angel: Oooh...
Spreadsheets used for complex tasks and evolving into complex algorithms was also the punchline of 1667: Algorithms .


Inbox

Explanation:
Email differs from "snail" mail, in that people often expect a prompt reply. Replying to an email may lead to another email response, thus leading to a "loop" of constant replies and responses.  Since an individual email is quick and cheap to send, people send lots of them.  Thus people get a lot of emails, and may spend a large portion of their day dealing with email.
Megan observes that maybe the Romans got a lot done because they did not spend time on email.  In doing this she plays on the email handling strategy named Inbox Zero, which they might not have had because the Roman number system had no symbol for zero.  This is of course redundant, as email did not exist at the time. [ citation needed ]
Inbox Zero is an approach to email inbox management espoused by Merlin Mann, with the idea that people should spend as little time as possible in their email inbox. To achieve this, one should check one's inbox as few times as practical, and quickly deal with all new emails by deleting, delegating, sending a short reply where possible or categorizing them for later tasks.  Basically it's a continuation of the "touch it once" strategy for dealing with physical mail.
The ancient Romans are one of the model historical societies, well revered for their culture and life. A common misconception is that Romans did not have a concept of the number zero. The Romans were aware of the concept of zero, but there is no numeral for 0 in the Roman numeral system, as Roman numerals do not have place values like Arabic numerals. A value of ten or greater is represented in Arabic numerals using 0 as a placeholder for empty place values. Roman numerals do not have such a placeholder digit, and so did not have a numeral for zero; the word nulla was used to refer to "zero" in the sense of "nothing". Various sources indicate that this eventually gave use to N as a Roman numeral for "zero", and such is the case for modern users of Roman numerals.
The title text refers to Hannibal's crossing of the Alps , a famous military campaign by Hannibal against the Romans. Randall claims that Hannibal needed to invade Rome to tell them to stop sending him so many emails. The reason for this was that Rome's email was sent from a " no-reply " email address, so Hannibal had no way of replying by email, and had to tell them in person. The real reason for Hannibal to cross the Alps was because he wanted to conquer Rome. He did not conquer Rome, so he never sent his "unsubscribe" message.
[Megan and Cueball are sitting at a desk, facing each other, each working on their laptop computers.] Megan: Answering email is the worst. It just leads to getting more email. Cueball: Yeah, email is a trap.
[Beat panel.]
[Megan looks up from her work on the computer.] Megan: I bet the reason the Ancient Romans got so much done was that they had no concept of Inbox Zero. Cueball: That explains it.


When I'm Back at a Keyboard

Explanation:
Cueball is texting someone on his phone. However, since with a full sized physical keyboard you can type with all of your fingers, which is usually a much faster and more accurate way than using an on-screen keyboard on a smartphone, Cueball cuts off the conversation and says he will get back to whoever he was talking to when he can type on an actual keyboard, presumably at home and on his computer.  While there are multiple techniques for making a smartphone increasingly easier to enter words into using its on-screen virtual keyboard , such as keyboard swiping, on-the-fly spelling and grammar checkers, and voice recognition to minimize using the keyboard at all, the combination of a full-sized keyboard along with a generous sized screen is hard to beat for speed and accuracy when typing larger blocks of text.
The joke is that despite claiming to be more proficient with a physical keyboard, rather than a digital one, Randall still goes into long rants through messages on his smartphone, whenever anybody brings up Jurassic Park .
There might also be a reference on Dennis Nedry, a character from the first Jurassic Park film. The programmer is responsible for a security sabotage and intends to be away from his keyboard only for a short while, but dies (not altogether) unexpectedly, worsening the situation in the park.
The title text shows a typical sentence from Randall after having been in a chat over his phone. Before the sentence he has written 1500 words on his phone, all related to Jurassic Park, more or less. When he finally have written his fingers off he then says that he will have to stop now but once back at a keyboard, and even though he just typed 1500 words on his phone, he is ready to type even more (5000 words) using his keyboard.
The widespread uptake of mobile devices has stark implications for user-generated content sites on the internet. According to a 2014 New York Times article, only one percent of the changes to Wikipedia articles were made via mobile devices, although they displayed about a third of all Wikipedia page views that year.
[Cueball is walking while holding his phone in both hands. A line from the screen on the phone goes to the text above him, indicating what he writes:] Cueball (texting): Sure, I can reply once I'm back at a keyboard and can type more easily.
[Caption below the panel:] I say this a lot for someone who routinely types thousands of words in text message conversations when someone brings up Jurassic Park .


Icon Swap

Explanation:
Randall denies having a social media addiction . However, he concludes that he must have some problem, as he opens his social media / news apps many times a day. He tries to remedy this addiction by rearranging the icons on his phone’s app launcher. Specifically, he swaps the app icon with that of an eBook reader, so opening the "social media app" would lead to the eBook reader, and vice versa. In this case, when he swaps a social media/news app with his E-book reading app, he ends up reading more books (as shown by the graph) because he is used to having his media app in its place, and is opening it up through muscle memory .
This results in the punch line, where he says that this causes him to read "a half-dozen" books before his muscle memory adjusts and not he stops opening his reader as often. Presumably, he changes the icons again in order to trick his muscle memory when he makes a conscious decision to read more books or use less social media.
Alternatively, Randall does not realize that he is reading books instead of a social media feed, and often gets through many books before realizing.
In the title text, Randall says that there is probably an eBook app in development that will use "breaking news alerts", typically sent as push notifications , about what is happening in the book, to prompt readers to continue reading more pages. This parallels how a news app works, which would send an alert when a new event occurs.
This topic is similar to one he went over in 477: Typewriter , where he is compulsively trying to check news websites despite using a typewriter.
[A histogram of books finished over time. Spikes occur at certain points, with arrows marked "Icon Swap" pointing to the point before them.]
[Caption below the panel:] I'm not saying I have a problem compulsively checking news and social media on my phone, but when I replace the social media app icon with my eBook reader, I read a half-dozen books before I get used to the change.


Unpopular Opinions

Explanation:
Everybody has their own preferences as to what movies they like and dislike, and when your like or dislike of a movie seems to be different than the majority of people, you could call your preference the "unpopular opinion" because your opinion is the less prevalent one. This often takes the form of "I hate this movie and I don't understand why everybody else seems to like it", but this comic is talking about the opposite form, which it categorizes as less common, namely "I like this movie and don't understand why everybody else seems to hate it."  The comic points out that it's relatively common to hate movies others appear to like, but the converse, in which you like a movie others seem to hate, is much harder to find.
To illustrate how hard it is to like a movie everyone else seems to dislike, the comic presents a challenge whereby you 1) identify a movie you definitely like, which 2) came out during your adult life (so it isn't tainted by childhood nostalgia ), and which 3) the majority of other people don't like, as measured informally by having a popularity rating below 50% on the Rotten Tomatoes website (a website that aggregates reviews of films).  Supposedly you will find it hard to find a movie that meets all three criteria. The rules prohibit a movie that the viewer finds "So Bad, It's Good" - the enjoyment of the movie must be genuine, for its positive qualities, rather than ironic enjoyment of its negative qualities.
The image in this comic gives an example of this effect, namely the movie Terminator Genisys , the fifth in the Terminator series, released in 2015. This series, about time-travelling killer robots, included the highly rated Terminator 2 (93% on Rotten Tomatoes), while Terminator Genisys is only 26%.
The title text refers to three movies in the Terminator franchise, Terminator 3: Rise of the Machines (2003), Terminator Salvation (2009), and Terminator: Dark Fate (due out later in 2019). The Terminator movie series has featured both time travel and trucks driving or attempting to drive into people, and Randall apparently finds himself drawn to such movies. He hopes that Dark Fate will be a good movie, but has low expectations, considering the less than stellar ratings of the last 3 movies (69%, 33%, and 26%).
A Tomatoes search ordered by release date limited to qualifying movies can help individuals verify the difficulty of finding such movies for themselves.
[Ponytail, Cueball, and Megan are all looking at their cell phones. Cueball is in the middle, facing out, holding his phone in both hands, while the two women face towards him with only one hand on their phones. Ponytail is tapping on the phone as shown by small lines over her fingers. they talk to each other, but before that, there is the following text above them:] Unpopular positive opinion challenge: Name a movie that... (1) you genuinely like (not "so bad it's good") (2) came out in your adult life post-2000, and (3) is rated below 50% on Rotten Tomatoes.
Ponytail: Wow, this is harder than I thought. Cueball: ...Terminator Genisys? Megan: Seriously?! Cueball: I like time travel, OK??
[Caption below the panel:]
When people talk about their "unpopular opinions" about movies, they usually mean hating something everyone likes, but liking something everyone hates is much harder.


Cumulonimbus

Explanation:
This comic follows the naming of clouds. As with other lists (like in 2022: Sports Champions ), it starts off as normal but then gets more unusual until it is unrealistic.
Cumulus The first panel shows a cumulus cloud , from the Latin for "heap". These are common clouds and are relatively small. Cumulus clouds form when warm (and thus rising) moist air condenses when it hits the dew point , the temperature at which relative humidity hits 100%. Cumulus clouds with sharp, defined borders are still growing. When they stop growing (because the rising moist air is exhausted), they get fuzzy and fluffy, and eventually dissolve. Cumulo nimbus The second panel shows a cumulonimbus cloud , from the Latin for "heaping raincloud", with the upper part about the same size as the lower part. Though somewhat like the cumulus cloud, it is more prone to causing rain and lightning. Cumulonimbus clouds, like cumulus clouds, grow vertically because of their moist warm air, but they have enough energy to  reach the top of the troposphere , giving them the distinctive anvil shape shown in the comic and their tendency to produce nasty weather. Cumulo nimbulo nimbus The third panel shows an even bigger cloud and names it cumulonimbulonimbus (Latin for "heaping rainy raincloud"). Here the scientific facts end and the humor begins. The cloud has the upper part about twice as large as the lower part. The humor here comes from building up an even bigger name by adding another "nimbus" element for the cloud as its size increases, suggesting that its growth as compared to the second cloud shown has made it even more "rainy". Cumulo nimbulo nimbulo cumulo nimbus The fourth panel shows an absurdly large cloud with three major layers and gives it the name cumulonimbulonimbulocumulonimbus (Latin for "heaping rainy rainy heaping raincloud"). This is a combination of the third and second cloud names in this comic, and indeed the fourth cloud looks a lot like the second one emerging out of the top of the third. This cloud may look like a super soaker , ready to spray water on everyone, or perhaps a faucet ready to open and pour water down. Alto cumu lenticulo strato nimbulo cirrus lenticulo mamma noctilucent The title text takes this comic to its logical extreme by naming a new cloud that has the longest name of them all and is also supposedly the rarest. Its name can be translated as "mid-altitude, heaped, lense-shaped, layered, grey, rainy, wispy, breast-like and lit at night". It mentions a common joke in weather communities, making fun of the common trope that thunderstorms form when "warm moist air" meets "cold dry air," an extreme oversimplification. A complicated cloud needs complicated processes, so Randall adds in "cold slippery air," then cursed air and nanobots , which makes the cloud impossible since neither of those exist. [ citation needed ]
The name of this cloud is a compound of the following cloud names: altocumulus : "heap up high"; these clouds are mid-altitude white patches. lenticular cloud , often shaped like a flying saucer. stratus : a layered cloud, effectively above-ground fog. nimbus : a grey cloud producing continuous rain. cirrus : a cloud that looks like thin, wispy strands. "lenticulo" gets repeated, perhaps indicating that there's a second disc in the cloud. mammatus : a breast-like cloud structure that forms at the bottom of some thunderstorm clouds, which signifies sinking air and is associated with severe storm activity and, in the central United States, tornado formation. noctilucent : a cloud-like structure formed from ice crystals, often formed after volcano eruptions and other cataclysmic events and illuminated by a just-set sun.
The International Cloud Atlas defines the cloud types that are recognized by the WMO, the World Meteorological Organization . It was first published in 1896. Similarly, IUPAC publishes a manual that allows chemists to name chemical compounds in a consistent manner. The Altocumulenticulostratonimbulocirruslenticulomammanoctilucent may thus be a pun on IUPAC, which (theoretically) offers a unique name for each possible strand of DNA and other complex molecules (such as Titin ). Therefore, Randall might have seen a unique cloud that has never been observed before, but yet, thanks to IUPAC-like cloud naming rules, he came up with a "valid" name for his observation.
[Drawing of a small cloud with with a label beneath:] Cumulus
[Drawing of a medium sized tall hourglass shaped cloud with a label beneath:] Cumulonimbus
[Drawing of a large cloud, larger at the top than at the bottom, with a label beneath:] Cumulonimbulonimbus
[Drawing of a huge and very complicated cloud in three layers, with a label beneath:] Cumulonimbulonimbulocumulonimbus


Dark Matter

Explanation:
Megan and Cueball are talking about dark matter , the mysterious invisible mass observed indirectly by the rate at which galaxies rotate. Megan states that dark matter's density in the solar system is 0.3 GeV/cm 3 , as claimed, for example, by Bovy and Tremaine (2012) "On the local dark matter density" in The Astrophysical Journal . Cueball does not understand what that means, so Megan explains that it equates to one squirrel's mass of dark matter in the volume of the Earth . In the final two panels, Cueball humorously misinterprets this as implying dark matter is actually one or more squirrels, and thereby provides the mass which causes squirrels to spin on bird feeders designed to deter them while birds, with lower mass, do not. This enrages Megan.
The gigaelectronvolt (GeV) is a unit of energy that can be converted to a mass using Einstein's formula E = mc 2 . It is typically used for subatomic particles, such as weakly interacting massive particles (WIMPs), one of several contending possibilities for the still-open question of the composition of dark matter, and one which Megan's uniform density figure implies constitutes most of it. For example, the mass of a proton is 0.938 GeV/ c 2 . However, it is common to omit the c 2 denominator, representing masses as GeV or MeV. A mass represented as 0.3 GeV is equal to 5.35 × 10 −25 grams [1] . Since the Earth's volume is 1.083 × 10 27 cm 3 Megan's figures imply that a squirrel has a mass of about 1.3 lb (1.083 x 5.35 × 10 27−25 g = 580 g [2] ), a typical weight for several species of common squirrels.
Squirrels are a recurring topic on xkcd, but are not a serious alternative to WIMPs as a scientific explanation for the composition of dark matter . Since the September 2015 detection by the Laser Interferometer Gravitational-Wave Observatory (LIGO) and subsequent confirmation by the Virgo interferometer of gravitational waves from unexpectedly many merging black holes substantially more massive than those produced by stellar collapse, primordial black holes (PBHs) have become a popular alternative explanation to WIMPs (or squirrels), attracting proponents at NASA, and other cosmologists for several reasons. But PBHs remain controversial, because if they constituted more than a very small portion of dark matter, alternative explanations would be almost entirely excluded.
Other alternative hypotheses for the observations suggesting dark matter, such as theories involving the gravitational force varying over different distances , often upset cosmologists as much as Megan is shown to be, because they violate the cosmological principle among other issues. Part of this frustration may be due to the fact that even after many decades of careful, tremendously expensive, and often stunningly beautiful experiments, none of the many explanations for dark matter or the observations suggesting it have as yet any support from direct empirical observations.
To help resolve this mystery, the title text imagines using a spinning bird feeder like a particle accelerator , colliding squirrels at relativistic speeds as if they were subatomic particles, to detect dark matter particles like the CERN accelerator discovered the Higgs boson . (Note, however, that accelerating even one squirrel to relativistic velocities would destroy the feeder along with any nearby birds, not to mention the squirrels, and the surrounding city.)
[Megan walks with Cueball. She is holding a hand out while telling Cueball something.] Megan: Dark matter density in the solar system is around 0.3 GeV/cm 3 Cueball: Is... that a lot?
[As they continue to walk and talk she spreads her arms out.] Megan: In terms of mass, it means the Earth contains one squirrel worth of dark matter at any given time. Cueball: Wow.
[In a frame-less panel Cueball stops while Megan walks past him. Megan is face-palming herself while looking down.] Cueball: Is there any way to find out which squirrel it is? Megan: No, it's not literally-
[Cueball holds his hand with one finger up in front of Megan, while she has turned towards him and is holding both arms up, possible with balled fist, as she shouts back at him, shown both with large fat letters and with small lines emanating above her head.] Cueball: Oh, that explains why they weigh enough to set off those spinning bird feeders! Megan: Dark matter isn't squirrels!


Geologic Time

Explanation:
Analogies to explain the passage of billions of years are often used in popular science explanations, to help compress these huge spans of time into something the human mind can comprehend; the football field analogy is one such analogy. The Earth is approximately 4.54 billion years old ; if you were to present a timeline of Earth as long as a football field (100 yards or 91 meters), then each inch of that length would comprise more than 1.26 million years of Earth's history and each millimeter nearly 50,000 years.
Megan , a geologist , tells a story about how small the timespan of human history is compared to Earth's total history. She does this to juxtapose it with normal human time-scales, to imply that her being two weeks late turning in her project is immaterial by the standards of the Earth's tremendous age. She tries to sell this story to Cueball and Hairbun , but Hairbun's response does not seem to bode well for Megan.
Megan's delay of two weeks would map to about eight nanometers on the football field.  The most powerful electron microscopes have a magnification of ten million, which would make it look like about eight centimeters (about three inches), so her statement about it being "too small to see even with a powerful microscope" is a bit of an exaggeration.  The most powerful optical microscope has 6500x magnification,( New York Times, March 8, 2011 ) which would indeed be inadequate.
Randall states in the caption that this is a trick that geologists always try to use when being late turning something in.
In the title text, Hairbun and Cueball reply by turning Megan's own argument against her. They promise to pay her for her work in what could be considered a short amount of time on the geological scale - which could easily be many, many times longer than Megan's own lifespan. Megan, like all working people, wants to be paid in a timely manner for her work, and would be deeply dissatisfied to have her payment delayed for so long. Thus, Hairbun and Cueball's rebuttal proves a point: when other people require you be punctual, it's easy to dismiss them as just being impatient; when you're the one who needs other people to be punctual, it's not so easy to criticize yourself.
The comparison with a football field is a typical, but doubtful practice to explain people what the size of an area is ( 1257: Monster ). Here it is used as an analogy with a one-dimensional timescale.
[Megan, arms spread out, is delivering a long-winded explanation to Hairbun and Cueball.] Megan: Imagine Earth's history as a football field, from the planet's formation at one end to today at the other. Megan: Complex life would be largely limited to the final ten yards. Dinosaurs appear at the five-yard line, the age of mammals happens in the last 1½ yards, and humans arise in the final few millimeters. Megan: All of written history would fit in a strip narrower than a single hair. Megan: "Two weeks" would be too small to see even with a powerful microscope. Hairbun: Mm hmm.
[Caption below the panel:] Geologists always try this when they're late turning something in.


E Scooters

Explanation:
At the time of publishing, motorized scooters or e-scooters were very popular, especially with the rise of ride-share companies such as Lime and Bird that use apps allowing users to rent the scooters by the minute. ( Randall uses "e scooter" or "E Scooter" for the comic's title. But in the comic White Hat does say e-scooter, which is also the way the Wikipedia article on e-scooters mentions them.)
Cueball drives up to White Hat on his e-scooter. White Hat asks him for his thoughts on the scooter; he is interested as he has heard so much about them. However, instead of just waiting to hear Cueball's response, White Hat then goes on to list four opinions he has heard other people say about e-scooters:
When White Hat finally stops talking, Cueball tells him that he has given this a lot of thought and says he will give him his opinion on e-scooters. But instead of choosing an opinion from  White Hat's list, or any logical opinion at all for that matter, Cueball starts making engine/vehicle sounds. This may indicate he doesn't care about any of White Hat's complicated opinions and is just excited about the fun of riding an e-scooter. In the last panel Cueball also makes "pew pew pew" sounds and other sounds from shooter-type video games, perhaps indicating that for him, riding a scooter is akin to the fun he gets from playing such video games.
Some people consider e-scooters as a "low-carbon car replacement", as they are better for the environment than polluting gas cars (while others consider the resources used in their creation and their disposal a bigger threat). Additionally, e-scooters have been touted as a form of "last-mile transit" - used to cover the "last mile" to your destination after taking other forms of public transportation. However, others consider e-scooters a public nuisance, as users often leave them on the sidewalk haphazardly; hence the question about them being clutter. The comment about them being specifically "Silicon Valley" clutter is due to the expense, the city-infrastructure needed, and the high-tech nature of these devices. Many of the e-scooter companies are also from the Silicon Valley area. Scooters have also been seen as dangerous ("unsafe toys"), as many users do not wear helmets when riding e-scooters (though Cueball is seen with a helmet in the comic, although not wearing it) or ride them at high speed on sidewalks with many pedestrians. Some cities have gone so far as to ban e-scooters from their communities .
Cueball's response of making onomatopoeic sounds which mimic the e-scooter is humorous for two reasons. First, e-scooters are fun and may seem futuristic, like something from his childhood. This would bring out a youthful and childish joy children have when making engine noises when playing with toy cars. He is acting like a kid because riding a scooter makes him feel like one. The second reason this is funny is that the scooters, being battery-powered, are nearly silent. He is making the sounds a traditional motorized scooter makes to fill in the audible gap. It is unclear why the scooter has lasers. Part of the joke is that there is no good or logical explanation for them. This forces the reader to come up with their own devious or honorable plan Cueball is executing. Not knowing why makes it more sinister and mysterious.
The title text refers to Dean Kamen, an American inventor best known for founding the Segway company. At the time of the invention of the Segway, it was billed as a revolution in personal transit, with articles (and Kamen himself) speculating that future cities might be entirely rebuilt around it and similar personal transporters. That buzz quickly died down, and Segways became the subject of a great deal of mockery. The text implies that Kamen might resent the fact that a similar vision has re-emerged and is once again being taken seriously, but without his invention. However, Segway actually manufactures scooters for e-scooter rental agency Lime .
[Cueball is getting off his e-scooter, with his bicycle helmet hanging on the handlebars. He has stopped right in front of White Hat who addresses him.] White Hat: Hey, you got one of those e-scooters! Cueball: Yeah!
[Cueball is now standing next to the e-scooter holding on to the handlebars with one hand. Both he and White Hat look down at the scooter.] White Hat: So what do you think? I hear so much about these things.
[A large panel with just White Hat who is spreading his arms out.] White Hat: Are they impractical and unsafe toys? Or a last-mile transit revolution?
[Closeup on White Hat holding both arms out and up with palms held up.] White Hat: A low-carbon car replacement? Or Silicon Valley sidewalk clutter?
[In a frame-less panel only Cueball and his e-scooter is shown.] Cueball: Well, having given it lots of thought, here is my opinion on scooters:
[Cueball is bending at the knees and holding on to the handlebars with both hands as White Hat is looking at him. Cueball starts making machine noises.] Cueball: Zooooooom! Cueball: Neeeeeoooormm Cueball: Vrrrm Vrrmvrmm Cueball: Wheeee!
[Cueball continues making sounds as in the previous panel. White Hat seems to have taken a step back.] Cueball: Pew pew pew! Cueball: Bzzzzt Kaboom! White Hat: Wait, why are there lasers? Cueball: Pew!


Old Game Worlds

Explanation:
Randall sits at his computer looking at a menu of games which have been ordered into three sections, New, Old and Very old games (see List of games below). At the bottom of this list, 2nd to last, he chooses to click on Super Mario Bros. which  then opens as shown in the next four panels.
This comic explores the difference between the real world, where artificial structures require constant upkeep and communities change with time, and the digital worlds of video games, where everything is static until the plot demands otherwise. Although online games do require server maintenance by the owners and sometimes receive major changes to their content, offline games are - and always have been - perpetual existences, unchanging so long as the data is intact. (This is later revisited in 2221: Emulation )
As the narration explores this incongruity, and theorizes about the idea of it not being so, the comic displays the alternative with the ubiquitous video game - Super Mario Bros. (1985) - as an example. Mario arrives in World 1-1 to find a Goomba expressing surprise that the plumber has deigned to return to the place where his first journey began. As he advances, he finds both signs of progress - a cellphone tower , an e-scooter , a drone - and signs of disrepair - damaged Warp Pipes , loose blocks. At World 1-4, he finds Toad ; in the game, Toad would warn him that the Princess is being held in another castle , but now, he's informing Mario that the castle has been remodeled into a Panera bakery.
This reflects common experiences of a person returning to a place they once knew well, but haven't seen in a long time. The atmosphere of the place may be changed by modern elements that hadn't existed before.  Buildings and other infrastructure may have decayed or fallen into disrepair.  And areas that have not been neglected will often be redeveloped, meaning that landmarks you remember may be repurposed or demolished to make room for something new. This tends to stir up feelings of nostalgia and loss in real life, when the settings of your memory no longer exist in the form that you remember.
The title-text abruptly switches to Mario's acceptance of the changes to World 1, and deciding to make the most of it by purchasing a cinnamon roll . "Coins" are the omnipresent currency of the Mushroom Kingdom and most other locations Mario visits in the Mario series, taking the form of large nondescript golden circles, usually with a rectangular indent in the middle.
The concept of an old, dilapidated version of the world of the original Super Mario Bros. was explored by Nintendo themselves in the Mushroomy Kingdom stage featured in multiple Super Smash Bros. games.
The first panel shows a list of games in approximately reverse chronological order of their release:
The first game in the Mario Kart series was Super Mario Kart from 1992. As can be seen that Mario Kart game would be older than Link's Awakening. So it seems likely Randall was referring to Mario Kart 64 from 1997, the first in the series to begin with Mario Kart leaving out the Super. With this in mind all the games in the two bottom sections are older than all those in the previous section. But they are not listed chronologically within the three sections.
Russian Subway Dogs is the newest game from 2018 (and at the time of this comic's release in August 2019, is the only one of the 13 games mentioned in this comic that does not currently have a Wikipedia entry).
Super Mario Bros., the game most prominently featured in the comic, is the oldest of the 13. The first version of Microsoft Flight Simulator , MS flight simulator 1.0 , was from 1982, but the list this comic specifies the third version, released in 1988.
Although the games in this comic appear to be grouped by date of their release, the time span covered by these groupings is not uniform. The first three games mentioned are from 2014-2018. The next four date from between 1997-2004, and the last six from between 1985-1996. With the earliest games grouped as 1985-1996, uniform grouping could split the later games between a group released in 1997-2008 and a group of games released in 2009 or later. If grouped by decades, 1985-1995 would potentially place the Escape Velocity game in the Old Games section instead of the Very Old Games section. Although some of these games did have releases intended to run on a 'Personal Computer' , the list in this comic seems to focus on games released for gaming consoles , with no mention of games released for first or second generation consoles which pre-dated the Nintendo Entertainment System (such as Pong published by Atari; Brain Wave, Haunted House, Interplanetary Voyage, & Wipeout for the Magnavox Odyssey ; & Adventure for the Atari 2600 ).
[A light gray drop down menu is shown with three sections split up with three grays lines split up with section titles in the same gray font. Beneath each section title is 3, 4 and 6 lines of black text. An white arrow cursor hovers over the second last option, which is thus highlighted with a dark gray background and white text.] New Games Subnautica Russian Subway Dogs Kerbal Space Program Old Games Worms Armageddon Elasto Mania Katamari Damacy Mario Kart Very Old Games Link's Awakening Escape Velocity SimCity Prince of Persia Super Mario Bros MS Flight Simulator 3
[A colorful scene is shown from the Super Mario Bros. side-scrolling game, the first level World 1-1. Mario with red hat and trousers is standing on the brown blocks beneath the blue sky. Another character in the game, Goomba, is standing in front of some green bushes. Above them is narration text:] Narrator: It feels weird that you can go into old games and the whole world is still there. Goomba: Mario? Mario: It'sa me! Goomba: What are you doing here?
[Mario stands between an e-scooter, a dismounted and broken Question Mark Box lying on its side and a cellphone tower. Narration continues above:] Narrator: Part of me expects to find that everything's changed.
[Mario looks at a damaged green but rusty Warp Pipe and there is a quadcopter drone flying by over his head. Weeds are growing both from the pipe and from the blocks he is walking on. Narration continues above:] Narrator: That pipes have rusted, walls have crumbled, bad guys have moved on.
[Mario has moved on to World 1-4, the castle has been replaced with a bakery. The blocks beneath his feet are now smaller and gray and above them is black background. The character Toad with the white hat with red circles is standing in front of a bakery disc with shelves of bread and cake behind it. There is a green sign on the front of the brown disk. Toad talks to Mario with white text in the black background. Above the black part of the image is more narration in a frame-less white section:] Narrator: That even our game worlds can't escape the passage of time. Toad: Thank you, Mario! Toad: But this is a Panera now! Sign: Panera


Serena Versus the Drones

Explanation:
Another comic which is a promotion of Randall's up coming book How To , to be released less than 3 weeks after this comic's release, on September 3, 2019. And this time permanent - as opposed to Disappearing Sunday Update from about two weeks before. It stars Serena Williams , an American professional tennis player and former world No. 1.
Most book advertisements feature laudatory quotes from famous people or reviewers, but here, Serena Williams is quoted as saying "It's a pretty bad idea" about Randall's idea of her attacking drones as given by the title of the comic. That idea is one of the chapters in the book and Serena Williams actually agreed to go and shoot tennis balls after an old drone with a broken camera. This can be read in the Blag post that is linked at the bottom of the comic: Serena Versus the Drones .  Unlike other books, "It's a pretty bad idea" is a pretty good quote for his "How To" book given that many of Randall's humorous explorations of scientific methods of doing usual and unusual things are pretty bad ideas.
As usual with Randall there is no need to click on the link, as the entire image is a link to the blog post. This was mentioned in 1572: xkcd Survey , and even earlier in the banner for his book tour for the what if? book.
The title text says that Serena Williams said that if she wanted to defend herself against drones and if she had to use sports equipment, she would use a tennis racket and ball. Notably, according to the Blag post, this would be ineffective compared to throwing.
[A panel at the top of the comic has a quote and to the right of the quote is a picture of Randall's new book. It is black with large blue text and smaller white text. On the book cover, in white drawings, are seen Megan with a ladder and either Black or White Hat (hard to say on black background). Both are looking up on Cueball who is floating in the air with a quadcopter drone beneath either leg, trying to plug in an electric light bulb in a naked lamp hanging down near him. It seems he has already removed the broken light bulb, as he has one in both hands. And now he tries to put in the new one. The blue text stating title and author can be read.] "It's a pretty bad idea." —Serena Williams on my idea
Book: How To Book: Randall Munroe
[Caption below this panel above another set of panel:] Which types of sports equipment would be most effective at bringing down a rogue photography drone? My new book features a real-world test by Serena Williams.
[A large panel shows Serena Williams, with curly hair and a very large ponytail, swinging her tennis racket to smash a tennis ball towards, and hitting, a quadcopter drone flying towards her. As the ball hits a small explosion seems to happen with the drone which is stopped in mid air. Above the drone are two other drones flying towards her, with one more below. There is a broken drone on the ground in front of her. Three tennis balls lie behind her.]
[Three smaller panels are beneath the large panel. The first panel is smaller than the other two and a bit higher up than they are and is overlaying the second panel. It shows Serena jumping with the racket held high. No drones are shown, but her shadow can be seen beneath her.]
[In the next panel she is seen smashing her racket into one of the drones, breaking a rotor off, she is still hanging in the air, her shadow beneath her and her legs partly behind the previous panel, which is covering most of the left part of this panel. Another drone is flying above her.]
[In the final panel she is seen standing again, turning around facing the other way, taking another swing at two drones that try to evade her. The ground is now filled with debris from several smashed drones.]
[Caption beneath the panels, with the "here" in link blue color... The entire image is a link, so no need to click on the here though.] To read an excerpt about Serena's drone battle, click here or go to blog.xkcd.com


Conference Question

Explanation:
Usually, at a conference or other event involving a speaker addressing a crowd, members of the crowd are given the chance to ask questions. This is intended so that people can perhaps ask the speaker to elaborate on a point they've made, or to ask the speaker's opinion on a topic related to their talk.
Occasionally, people at such an event will use (or, rather, abuse) the opportunity to ask a question to instead provide their own (unsolicited) opinion or statement. Such statements are often preceded with something along the lines of "I have a question. Well, less of a question and more of a comment." This formulation in particular has attracted a lot of criticism for not adding anything to the discussion and for pulling focus away from the speaker.
In the comic, this idea is taken to an extreme, with Beret Guy not only transforming the opportunity to ask a question into an opportunity to make a statement through successive rephrasing, turning this into an opportunity to show off a bug he has found. This is accomplished by using a multitude of synonyms in a continuum of relatable word pairs, except near the last: "question" and "comment" are similar, as are "comment" and "utterance", but the extremes, the difference between the first and the last in the entire set (in this case "question" and "friendly bug") is profound. In a way, this segue is meant to be similar to how, in the lines of a color spectrum, red fades into yellow: gradually, and with no abrupt transitions in color ( YMMV : CGA versus 4K ).

Question. A question is what the crowd member is expected to provide, such that the speaker or a panel member could provide a related answer.
Comment. A comment by a crowd member, is when they just say something they believe, without expecting an answer, giving the speaker or panel members nothing to do. This may be seen as annoying by everyone else, as the crowd did not come to hear the opinion of other crowd members. But answers to relevant questions would be interesting to the crowd and the panel.
Utterance. An utterance is just making a noise, which may or may not be actual words, or if actual words it may not be a complete sentence.
Air Pressure Wave. Sounds are literally pressure waves in the air.  So this could be a simple sound, or not a sound at all depending on the severity of the wave.  It might be the person simply blowing.
Friendly Hand Wave. Now instead of using his mouth to generate an air pressure wave, he's producing it with his hand, in a manner intended to be interpreted as "friendly".  Many times hand waves are done in a friendly manner, designed more for the visual appeal than the amount of air pressure waves they generate.
Friendly Bug. Now he is no longer doing anything himself, except to point out the fact that he has found a bug or insect , which he anthropomorphizes as being friendly.
Want to meet it? He has decided that he and the friendly bug are actual friends and ironically comes full circle by finally asking a question, though presumably whether the speaker wants to meet a bug is not related to the topic of the speaker's talk.
The title text takes the opposite route of Beret Guy, and each step instead refers to successively worse forms of magic spells that would, presumably, have a negative effect upon the listener. Starting from a mere utterance and then using Beret Guy's "it is less than" scheme, it progresses over worse and worse curses, ending with an unforgivable curse!
Utterance. It begins with "utterance", which was also used by Beret Guy. See above.
Incantation. Incantation , or a spell, is a magical formula intended to trigger a magical effect on a person or objects. It is not necessarily with evil intent.
Malediction. A malediction is another word for curse (the prefix "mal" being a Latin root meaning "evil"). This is always with evil intent.
Word of Power. "Word of Power" could refer to the dragonish form of magic in The Elder Scrolls V: Skyrim , or the early 1st edition Dungeons & Dragons high level spells .
Unforgivable Curse. The term " Unforgivable Curse " refers to a set of three spells from the Harry Potter series, said to be so evil that their use on another person is unforgivable and illegal. The three spells are able to mind control ( Imperius ), torture ( Cruciatus ), and kill ( Avada Kedavra ) their target. It is unclear which spell is implied, though if it was accurate to call it a singular word of power, it is unlikely to be the killing curse.
The title text can be interpreted as a reply by Hairy (the speaker) to Beret Guy, indicating his annoyance at the topic being derailed. It could also be representative of Randall's feelings towards those who abuse the opportunity to ask a question in order to make a statement.  Randall has recently done some book tours and was at San Diego Comic-Con last month where he served on various panels, so he probably has had personal first-hand experience with these kinds of circuitous non-questions.
[Hairy stands on a podium having just addressed a crowd of seated people. Beret Guy stands in the middle of the crowd, addressing Hairy. One of Beret Guy's hands is raised at chest height. The front row consists of Cueball, Ponytail, another Hairy, Megan, Hairbun, Danish and another Cueball.]
Beret Guy: I have a question. Beret Guy: Well, less of a question and more of a comment. Beret Guy: I guess it's less of a comment and more of an utterance. Beret Guy: Really it's less an utterance more an air pressure wave. Beret Guy: It's less an air pressure wave and more a friendly hand wave. Beret Guy: I guess it's less a friendly wave than it is a friendly bug. Beret Guy: I found this bug and now we're friends. Do you want to meet it?


Review

Explanation:
This comic is a five of five star review of planet Earth , by Randall , depicted as Cueball in his profile picture. The review is written as a video game review, praising the size and realism of the world. The comic's humor draws from the fact that Earth is a completely real object and shouldn't be rated on the same lines as a video game, and the fact that there's no place that the Earth can be reviewed (with the possible exception of The Hitchhiker's Guide to the Galaxy ). The "huge world" remark is a play on Open world games like Minecraft , which are praised when their size allows hundreds of hours of exploration; exploring Earth would allow more than a lifetime of novelties.
The title text states that the 'controls are hard to figure out', possibly alluding to the fact that it takes a lot of time to learn how to walk and talk, a rather basic thing in most video games, or to the fact that it is in general hard to navigate around in one's life, as has been the subject of many comics.
Earth (or humans and other life forms on Earth) has many problems at the moment, such as climate change , overpopulation , gun violence , sexual violence , censorship , poverty , and increasing depression , to name just a few.
However, this comic also serves as a reminder that, overall, the world is a five-star world. It reminds us to look around: there's so much world to explore! And also that it is worth preserving for future generation to play around on. It is not a game that grows outdated and will be replaced by a new and better version next year...
While there aren't any games that can recreate the detail that reality has (Due to the computing power required to do such a thing would be on an intergalactic level to recreate earth 1 to 1 in a simulation), there are some games that can either attempt to have a map that is similar in area, the graphic levels become close to reality, or difficult game-play/hard to learn controls.
Examples of such games that attempt these things would be: Minecraft, No Man's Sky , The Elder Scrolls V: Skyrim , Grand Theft Auto V , The Legend of Zelda: Breath of the Wild , The Witcher 3: Wild Hunt , QWOP , Getting Over It with Bennett Foddy , and any of the Souls (series) , which includes Demon's Souls , Dark Souls , Dark Souls II , and Dark Souls III . Some people like to include games like Bloodborne , Sekiro: Shadows Die Twice , and Elden Ring into the same series as the Souls series due to similarity's to those games, and because they were developed by the same company.
[A profile picture of Cueball in a small frame is next to five solid yellow stars. Below this is a review:] ★★★★★ Great graphics, huge world
[Caption below the comic:] My overall review of Earth