My Phone is Dying

Explanation:
Beret Guy's phone is about to "die". Cueball assumes this just means that the battery is running out and it needs to be recharged, but the phone in question appears to "die" in a way analogous to the life and death of a star: expending its fuel while heating up and expanding before ultimately losing its outer layers and becoming a white dwarf or similar "lesser" star. The technology of mobile phones can be seen as doing things analogous to this on a large scale, especially for people who used landlines before mobile phones became common. However, this is something phones usually don't literally do. [ citation needed ]
Stars constantly undergo fusion reactions. The pressure generated by these reactions counteracts gravity, preventing it from collapsing the star during its main lifespan. As the hydrogen mostly fuses into helium in the core, the core gradually becomes more dense and the region of fusion gradually moves away from the center. Then, the star grows in size, reaching the stage of a red giant . When most of the "fuel" for fusion has been consumed, gravity will collapse the star into a white dwarf while the outer layers are shed. For stars much more massive than the Sun, there will be a supernova explosion caused by a violent collapse, which is very powerful (and leaves behind a neutron star or a black hole , depending on how much mass is left after the supernova). Stars with more hydrogen fuel tend to burn brighter and faster. Beret Guy's refusal of a charger is probably a reference to this.
Both a supernova explosion and the collapse of red giants into white dwarfs shed their outer layers, which is referenced in the title text. Once extra mass is added to the dying star, analogous to "charging", the process only accelerates. (Randall also explains this in Short Answer Section .) The phone seems to have a certain mass because Beret Guy expects it to go (super)nova. Charging the phone may lead to a type 1a nova .
The comic also plays on the release of two new iPhone models with bigger screens, planned for 2 days after the release of the comic.
The comic could be also explained by the characteristics of Li-ion batteries, which are used in most cellphones. At the end of their useful life, these batteries may grow a bit . In case of severe physical or thermal damage or multiple electrical failures, this type of battery can indeed overheat, leading to a thermal runaway reaction inside. That would result in the battery growing and eventually exploding . Connecting a charger to a battery failing in this manner would probably make the process faster .
The title text implies that after Beret Guy's iPhone goes (super)nova, it will become either a "slowly fading" Palm Pilot, a calculator, or a two way pager: this would be the cellphone equivalent of a white dwarf (evidenced by the faint and slowly fading glow), neutron star , or black hole (evidence: black holes emit "information" in the form of Hawking radiation and have at one time been suspected to be half of a two-way portal through spacetime, along with a " white hole ").
Additionally, some particles and atoms decay by breaking into smaller, more elementary particles. It may be humorously implied that a PalmPilot (an early personal data assistant and precursor to the smartphone), a calculator (a very simple electronic device), and two-way pager (a device for sending and receiving short text messages) are the more elementary components that make up an iPhone.
[Cueball stands on the left while Beret Guy walks in from the right, carrying a smartphone.] Beret Guy: My phone's about to die.
[The phone is now subtly larger.] Cueball: Where'd you get a big iPhone? I didn't think they were out yet. Beret Guy: It's my regular one. It's just dying.
[The phone increases in size again. Beret Guy now holds it in both hands.] Beret Guy: As it consumes its battery, it heats up and expands. Beret Guy: Soon it will swell to enormous size, engulfing us both.
[The phone is now in the size of Beret Guy's torso; he is clutching it to himself. Cueball is pointing off-panel.] Beret Guy: Then it will collapse in a violent explosion! Cueball: ...do you want to borrow my charger? Beret Guy: That would only make it run out faster!


Conversation

Explanation:
Cueball and Megan are on a first date and Cueball is trying to strike up a conversation by asking Megan what she does in her free time . Megan has probably been dreading this question, because she answers that her free time activity consists of trying to figure out how to respond if asked what she does in her free time. Cueball answers soothingly, but Megan's anxiety gets the better of her and she leaves abruptly.
During Megan speaking, Cueball finished all of his drink. He may have been surprised by the reply, and Megan sensing this contributes to her leaving.
The title text implies that she also spends her free time wondering what to write in her diary (with no success).
Both the comic and the title text are examples of self-referential humor. Megan recognises that she spends her free time thinking what to say about her free time, so she must spend some of that free time thinking about her thinking about her free time. Such self-referential loops are often disturbing, since they contain within them potential for infinite regression . On the other hand, there is a simple way to exit the loop before any recursion: Megan has already decided what to say when asked what she does in her free time, and she has figured out what to write in her diary. But on realising this, Megan would have to find something else to occupy her free time, such as going on a date.
[Cueball and Megan are sitting at a table with drinks.] Cueball: So, what do you do in your free time?
[Close up on Megan's face.] Megan: Mostly I sit around worrying someone will ask me that, and try to think of a good answer.
[Back to original shot.] Cueball: That's not a bad answer. Megan: It's all I've got. Now that it's done, I should go. Bye! [She gets up and leaves.]


En Garde

Explanation:
Two Cueball -like guys are preparing to fence. But only the left seems ready. He says "en garde!", hence the title, a fencing call literally meaning "be on your guard" (from French). The call is used to order the participants to take their position, in a similar way to the “on your mark” command in racing. The other two commands are “[tireurs, êtes-vous] prêts?” (“[combatants, are you] ready?”) and “allez” (“go”). The right participant takes this to mean being "guarded" emotionally.
"What are you thinking?" is a common question used to deepen a conversation, typically between close friends or lovers. The person being asked may take a moment to consider what they are thinking and whether or not it would be appropriate to share with the asker. If the person being asked is emotionally comfortable with the asker, they may answer immediately without fear of judgment or ridicule. Such a level of comfort between two people generally takes a long time to develop.
After the right fencer has explained why he is always "en garde", the left fencer asks if could be a little less so. But the answer is no since the right fencer acknowledges that he has been hurt before, and thus makes it even more difficult for him to let down his guards. Obviously the right fencer has had bad experience from previous relationships, maybe one where he was ridiculed after sharing his immediate thoughts.
The title text takes this further with the "touch" call, used to indicate to a participant that they have been "touched" by their opponent's blade, and therefore the attacker receives a point. The right participant counters this claim by saying his emotions have "priority" (or right-of-way), implying he was blocking out ("parrying") the touching feelings. Fencing right-of-way rules can make a move invalid when another move has priority, but generally refer to physical actions on the participant's part.
[Two Cueball-like guys wearing fencing mask (with gray front over their faces and a strip around their neck) are standing facing each other. The left fencer holds one arm up behind him and the other with the rapier like sword pointing toward the right fencers mask, ready for fencing. The right fencer holds both arms, and thus also the sword, down.] Left fencer: En Garde! Right fencer: OK.
[In a large frame-less panel where they keep standing in the same position the right fencer talks at length.] Right fencer: No matter how long we know each other, when you ask "What are you thinking," Right fencer: I will always pause before answering.
[Same as the first panel, although the left fencer has lowered the point of his sword so it points straight to the right.] Left fencer: Maybe a little less guarded? Right fencer: No way. I've been hurt before.


Tasks

Explanation:
Cueball appears to be asking Ponytail to write an app that determines if a given picture is (1) taken in a national park, and (2) a picture of a bird. The first question is generally harder for a human to answer, but easy for an app that has access to location information and a geographic information system (GIS). The second one is easy for a human but much harder for a computer. This illustrates Moravec's paradox from the 1980s in a modern context. By the 1950s computers were useful for tasks like trajectory optimization , generating novel mathematical proofs , and the game of checkers , so such high-level computation and reasoning tasks that were hard for humans turned out to be relatively easy for them. On the other hand, it turns out to be hard to "give them the skills of a one-year-old when it comes to perception", as Moravec wrote.
In order to determine whether the user is in a national park, Ponytail plans to determine the user's location using the mobile device. This location will then be cross checked with a geographic information system (GIS) which will be able to determine whether the coordinates lie within a national park boundary.
Determining whether an image is of a given kind of natural object is far more difficult. This task falls into the area of computer vision . One of the goals in computer vision is to detect and classify objects within an image. This is a very challenging task for a number of reasons.
Firstly, humans use size, edge-assignment, movement, and stereoscopic vision when looking at a scene (not a picture of a thing, but the thing itself) to discern individual objects and then categorize them as foreground or background . A photograph, however, is a static, monoscopic image that can only provide size and edge-assignment clues. Humans are only able to discern objects from background in photographs by comparing the photo against all of the things they've seen and everything they've learned about those things over the course of their life and identifying matching patterns .
Secondly, the quality of the photograph will have an impact on a computer's ability to match patterns. For example, the object in the photograph might be partially visible or occluded. In the case of a living bird, additional complications arise from the variations among individual birds of the same species and differences in pose (flying, perching in a tree, etc.). Differentiating between visually similar objects can result in false positives. For example, is it a photo of a bird in flight or a plane (or superman!) ? Ponytail's estimate of 5 years may be overly optimistic (see 678: Researcher Translation ).
Today's state-of-the-art algorithms for solving this kind of task mostly use local features (e.g. SIFT or SURF in combination with a support vector machine or convolutional neural network ).
The subtitle refers to "CS", which is a common abbreviation for " Computer Science ", of which artificial intelligence and computer vision are sub-disciplines.
The title text mentions The Summer Vision Project and Marvin Minsky of MIT. In the summer of 1966, he asked his undergraduate student Gerald Jay Sussman to "spend the summer linking a camera to a computer and getting the computer to describe what it saw" . Seymour Papert drafted the plan, and it seems that Sussman was joined by Bill Gosper , Richard Greenblatt , Leslie Lamport , Adolfo Guzman, Michael Speciner, John White, Benjamin, and Henneman - in case the multiple Wikipedia links don't give it away, know that this is sizable cross-section of the AI researchers of the period). The project schedule allocated one summer for the completion of this task. The required time was obviously significantly underestimated, since dozens of research groups around the world are still working on this topic today.
A month after this comic came out, Flickr responded with a prototype online tool to do something similar to what the comic describes, using its automated-tagging software. According to them, the bird solution "took us less than 5 years to build, though it's definitely a hard problem, and we've still got room for improvement".
[Ponytail sitting at a computer with Cueball standing behind her.] Cueball: When a user takes a photo, the app should check whether they're in a national park... Ponytail: Sure, easy GIS lookup. Gimme a few hours. Cueball: ...and check whether the photo is of a bird. Ponytail: I'll need a research team and five years.
[Caption below the panel:] In CS, it can be hard to explain the difference between the easy and the virtually impossible.


Reduce Your Payments

Explanation:
Black Hat walks into a room where Cueball sits in an armchair. Black Hat says to Cueball that he can reduce his mortgage payments, while holding a docket of paper, presumably Cueball's payment check, that looks like it has been dipped into a liquid of some kind. Black Hat uses the same formulation many Internet advertisements use: "Discover this (strange/new/amazing...) trick to (lose weight/reduce your mortgage payments/meet amazing women...)" known as clickbait . Cueball wants to know how and Black Hat responds by mentioning sodium borohydride (NaBH 4 ) . Since Cueball fell for Black Hat's bait he exclaims, "I hate you."
Sodium borohydride is a strong reducing agent , meaning in a chemical reaction it will " reduce " another substance. It is in fact used during the manufacture of paper , in order to bleach the natural colour from the pulp and improve the resulting paper's brightness, opacity, ink-absorption, and strength (among other properties).
This comic is a typical switcharound pun. Cueball expects the value on a bill paid to be reduced, while Black Hat uses the chemical meaning of reducing , which would result at a minimum in the bleaching of all ink from the bill therefore making it unreadable.
The complementary chemical reaction to reduction is oxidation (mentioned in 1693: Oxidation ), which is what happens if the paper mortgage payment is burned, as referred to in the title text. They go together in redox reactions, which generally involve electron transfer from the chemical species which is oxidized to the one which is reduced. In that case, the pun about light (to start a fire) is that a reduced financial weight may seem light (not heavy). However, some forms of paper - particularly those used for i.e. receipts - possess a slight coating that limits their flammability. Cueball's statements appear to be made with such a paper, thus preventing Black Hat from burning the statements.
[Cueball sits on a sofa and Blackhat walks into the frame from behind.] Blackhat: I discovered this weird trick for reducing your mortgage payments! Cueball: What? Blackhat: Sodium borohydride. Cueball: ...I hate you.


iOS Keyboard

Explanation:
It looks like Randall has been playing with his Apple device after installing the recently released iOS 8 update. The comic is referencing the autocomplete function on the iOS virtual keyboard. A comparable feature is also available on other operating systems, like Android. When the phrase, for example, "Revenge is a dish best served" is typed, the keyboard will suggest “by” followed by “a” then “group” and so on.
The top of the comic, where the keyboard is shown, is a reference to the character Sherlock Holmes, a detective who is often attributed the famous line "Elementary, my dear Watson" (despite having never said that in the canon). In Randall's typing history, the word "dear" is most often followed by "lord", "friend", or "friends," and thus the phone suggests those words as a likely continuation of the line.
The title text continues, by showing more actual results from keyboard predictions from other movie quotes.
The following movies are referenced in the comic and title text:
An older comic 1068: Swiftkey is also about keyboard predictions, but without any preceding text (by the Swiftkey keyboard application instead of the iOS 8 keyboard).
It is similar to 2169: Predictive Models .
Movie quotes [Top picture shows a line typed on an iPhone.] Elementary, my dear [Then the next line shows the words suggested by the virtual keyboard.] Friend | Lord | Friends [Below are the visible part of keyboard. In the second line only the top of the letters can be seen.] QWERTYUIOP ASDFGHJKL [Below is a new sub heading above six pictures arranged in two rows.] According to iOS 8 keyboard predictions [For each of the six pictures a part of the text is black, and the other part is light grey. Below the black text is written in bold letters.] [Picture 1: Cueball stands with a machine gun.] Cueball: Say hello to my little sister and my mom and my dad and my friends [Picture 2: A girl stands next to her dog with a basket.] Girl: Toto, I've a feeling we're not going to the gym today [Picture 3: Bond talks to Megan.] James Bond: Bond, James Bond yields [Picture 4: A pilot operates his plane and talks to Cueball behind him.] Pilot: I'm a leaf on the wind. Watch me play the piano [Picture 5: A guy with dark hair stands behind a jagged edge.] Goonie: Goonies never say anything [Picture 6: A dwarf with long beard and helmet stands with an axe.] Off panel left: You have my sword. Off panel right: And my bow. Dwarf: And my dad


Move Fast and Break Things

Explanation:
Cueball appears to be at a job interview, proudly stating his motto to the interviewer Ponytail .
"Move fast and break things" is a saying common in science and engineering industries. In that context, it means that making mistakes is a natural consequence of innovation in a highly competitive and complex environment. In particular, it was adopted by Mark Zuckerberg at Facebook (who even went as far as to say that 'breaking things' is a necessary feature of moving 'fast enough' ).
While in software development it is unusual for any great harm to result from breaking things, the jobs listed in the comic are ones where there are serious consequences of mistakes. Some would result in dangerous or deadly situations, while others would just end up with broken packages etc. It's not clear what job Cueball is interviewing for; one suspects it's probably one that belongs in the 'breaking things is bad' group.
The results of moving fast and breaking things for the listed jobs might include:
The title text posits a morbid scenario where Cueball keeps running over funeral attendees, generating the need for more funerals. It also implies that Cueball is currently being interviewed for the position of driving a hearse, as he has yet to be fired.
[Cueball sits in a chair, leaning back with his arm resting on the back of the chair during a job interview. Ponytail is sitting in a chair behind her desk which is between them.] Cueball: My motto is "Move fast and break things." [Below the panel follows a list:] Jobs I've been fired from Fedex driver Crane operator Surgeon Air traffic controller Pharmacist Museum curator Waiter Dog walker Oil tanker captain Violinist Mars rover driver Massage therapist


Data

Explanation:
"Kirk vs. Picard" is a debate that many Star Trek fans engage in — specifically which was a better captain of the starship Enterprise on the TV show. Captain James T. Kirk and Jean-Luc Picard each were captains of the ship in different periods (Kirk was captain of USS Enterprise (NCC-1701) in The Original Series , while Picard was captain of USS Enterprise -D (NCC-1701-D) in The Next Generation ), but fans argue over who was the "best". Most third-place candidates are pretty distant, resulting in a more multi-faceted debate. Cueball seems to be looking at results of polling for this third most popular character.
The humor in this comic stems from the fact that the Latin word data is a plural form of the word datum ‘a piece of information’, and that originally English followed Latin's lead and treated data as plural. However, in more recent English, usage of datum has faded to the extent that data is treated as a collective noun . This usage is becoming increasingly (but not universally) accepted as grammatically correct — the Wall Street Journal , for instance, recently announced that it is moving away from saying "data are," while the New York Times' manual of style allows for both variants depending on usage scenario; USA Today , however, is consistently using data as a plural ("data are"). Naturally, the purists insist on the form that is correct from the Latin grammar point of view and see "data is" as an example of a subject-verb agreement error. This type of "error" is present in the beginning of the sentence that Cueball is citing ("According to this polling data," while certain traditionalists would hold that the grammatically correct variant would be "According to these polling data").
The second error in the same sentence is due to the fact that Data is a character from Star Trek: The Next Generation. Since it is a character's name, when used to refer to the character, "Data" should always be treated as singular.
By reversing the verb agreement in both cases, Cueball is going out of his way to annoy grammatically obsessed people.
The title text suggests the mocking of language pedants/amateur grammar Nazis by hypercorrecting one's use of language. The sentence itself is an example of this:
This comic complements two of the My Hobbies comics 326: Effect an Effect (which discusses the trolling of amateur grammar Nazis) and 1405: Meteor (which mocks pedantry). This comic could also just as well have been labelled as one of Randall's Hobbies.
This comic also appears to be an example of self-irony as the author himself has previously exhibited certain inclination to insist on grammatically strict mode of usage of words loaned from Latin. One such example is the fact that xkcd's online discussion forums are called fora , which is a correct plural nominative form of forum in Latin.
[Cueball reading off a smart phone to someone off-screen.] Cueball: According to this polling data, after Kirk and Picard, the most popular Star Trek character are Data. Off-screen voice: Augh! [Caption below the frame:] Annoy grammar pedants on all sides by making "data" singular except when referring to the android.


Proteins

Explanation:
In this comic, Cueball is asking Megan what she does, to which she replies that she works on software to predict protein folding. There are many folding prediction software programs. Some of the most well known are [email protected] , [email protected] and FoldIt .
Protein folding is the process by which proteins, which are floppy, unstructured chains of amino acids when initially synthesized in a cell, assume a stable, functional shape. If the folding process does not complete, or completes incorrectly, the resulting protein can be inactive or even toxic to the body. Misfolded proteins are responsible for several neurodegenerative diseases, including Alzheimer's disease , amyotrophic lateral sclerosis (ALS), and Parkinson's disease , as well as some non-neurodegenerative diseases such as cardiac amyloidosis.
Cueball asks Megan why it is such a hard computational problem; Megan's response is to ask Cueball if he's ever folded paper to make a crane . When he responds in the affirmative, she then compares the problem of predicting protein folding to creating a living crane by the paper-folding process. The analogy is that a protein cannot just fold to a figurative representation of a bio-molecule, the way a paper crane superficially resembles a live crane; the protein must assume an exact, perfect fold in order to be functional.
Levinthal's paradox is a thought experiment, also constituting a self-reference in the theory of protein folding. In 1969, Cyrus Levinthal noted that, because of the very large number of degrees of freedom in an unfolded polypeptide chain, the molecule has an astronomical number of possible conformations. For example, a polypeptide of 100 residues will have 99 peptide bonds, and therefore 198 different phi and psi bond angles . If each of these bond angles can be in one of three stable conformations, the protein may misfold into a maximum of 3 198 different conformations (including any possible folding redundancy). Therefore, if a protein were to attain its correctly folded configuration by sequentially sampling all the possible conformations, it would require a time longer than the age of the universe to arrive at its correct native conformation. This is true even if conformations are sampled at rapid (nanosecond or picosecond) rates. The "paradox" is that most small proteins fold spontaneously on a millisecond or even microsecond time scale. This paradox is central to computational approaches to protein structure prediction.
As Cueball mentally turns over the hypothetical process of folding paper to make a living crane, he wonders if he is allowed to perhaps "cut" the paper to make more complicated folds available. In origami, purists [1] considered it as cheating if you cut the paper or use more than one sheet of paper, which is why Cueball asked if he was 'allowed' to do such in the hypothetical exercise they are discussing.
Megan replies "if you can fold a Protease enzyme;" these are proteins whose job it is to break down (i.e. "cut") other proteins, often in very specific ways. In this manner, Protease enzymes are analogous to extremely specialized scissors, so Megan is effectively saying "You can make cuts if you can fold yourself a pair of scissors." Of course, when trying to predict the folding trajectory in nature of a protein A, and one is allowed to make cuts during the process, one is making the assumption that the Protease that cut protein A is already folded and functional. In other words, making cuts while folding might actually make the process more complicated, not less, as now you have to consider how the cutting enzyme is folded, too.
The title text refers to the result of folding a flapping bird in origami. By pulling the tail, the head will move forward and down. However, since the joke is about folding proteins, this idea is extrapolated to include the folded proteins. The C-terminus (end of the protein chain), in this case analogous of the tail, if "pulled" would cause a created cavity or tunnel to squeeze, much like pulling a knot would do the same.
[email protected] ( [email protected] ) is a distributed computing project which aims to simulate protein folding for research purposes. Rather than the traditional model of using a supercomputer for computation, the project uses idle processing power of a network of personal computers in order to achieve massive computing power. Individuals can join the project by installing the [email protected] software (there is also a web version that can be run using Google Chrome) and are then able to track their contribution to the project. Individual members may join together as a team, with leaderboards measuring team and individual contributions.
Note that most modern computers do not "waste" computing time as much as older ones. They dynamically reduce their clock speed and other power consumption at times of low usage. If you donate computer time, you are probably also donating a bit of money to the cause in the form of your electricity bill. Many people consider this to be more fun, convenient and efficient than donating via credit card.
[Cueball is talking with Megan.] Cueball: What do you do? Megan: I make software that predicts how proteins will fold. Cueball: Is that a hard problem? Megan: Someone may someday find a harder one. Cueball: Why is it so hard? Megan: Have you ever made a folded paper crane? Cueball: Yeah. Megan: Imagine figuring out the folds to make an actual living crane. Cueball: ... just folds? Can I make cuts? Megan: If you can fold a protease enzyme.


Marriage

Explanation:
The comic notes a curious inversion between the timing of legal and popular opinion trends for interracial marriage vs. same-sex marriage. In the 11 years between Massachusetts first legalized same-sex marriage and the comic's publication, at no point had there been more people living in states where it's legal than there are people who support its legality. This stands in stark contrast to interracial marriage, which was legal for the majority of the population for over 50 years, and for the whole country for 28 years, before it was approved of by the majority .
Note that poll questions are slightly different: "Do you approve of interracial marriage?" vs "Do you think same-sex marriage should be legal?" It could be argued that fewer people would approve of these marriages than would support legalizing them, which may explain part of the discrepancy. But there are more factors at work, the effects and relative importance of which are not clear.
Two days before this comic came out, the United States Supreme Court declined to hear appeals to decisions that had legalized same-sex marriage in five states. The court's refusal to hear the appeals was widely considered a surprise, and had the immediate effect of pushing the percentage of people living in states where such marriages are legal past 50% . The decision has also led to considerable speculation that there will be a surge of similar decisions applying to other states, especially to the six states that are in the same appeals circuits as the previous five, and to the three in the same circuit as Idaho and Nevada, where same-sex marriage bans were struck down a day after the Supreme Court's decision (although the decision in Idaho and Nevada has yet to take effect).
On June 26, 2015, the Supreme Court of the United States of America ruled in a 5-4 decision that access to same-sex marriage was a right protected by the Constitution, thus raising the percentage of states with legal same-sex marriage to 100%.
See also: Wikipedia: Anti-miscegenation laws in the United States
Legal controls concerning interracial marriage in the US (known since 1863 as miscegenation ) have been significantly harder to track as a single statistic, due in part to the fact that such controls existed in several of the American British colonies before the United States formed, and complicated somewhat by the changes in territory claimed by and fluctuations in overall population (and methods of counting the population) of the United States over that time period. Depicting this as a simple percentage of US population over these earlier times would be far less meaningful outside of the context of these other fluctuations.
Start of line Prior to ca. 1940 and continuing to 1948: Since the establishment of the United States, most states have had anti-miscegenation legislation in one form or another. Only nine states (Connecticut, New Hampshire, New York, New Jersey, Vermont, Wisconsin, Minnesota, Alaska, Hawaii) and the District of Columbia never enacted such legislation. Earlier repeal dates range from 1780 in Pennsylvania to 1887 in Ohio, though none were repealed between 1887 and 1948.
First rise October 1948: Supreme Court of California overturns the state anti-miscegenation law in Perez v. Sharp .
General upward trend 1951–1967: (in order of repeal by year) 13 states repeal anti-miscegenation laws prior to rulings at the federal level of government, largely encouraged by comparisons to similar laws promoted by opponents in World War II and other civil rights movements and victories.
Last spike 12 June 1967: The U.S. Supreme Court rules in Loving v. Virginia that the 16 remaining state-level anti-miscegenation laws are unconstitutional, rendering such laws thereafter ineffective.
See also: Wikipedia: Same-sex marriage in the United States
Start of line 2003: Massachusetts Supreme Judicial Court rules in Goodridge v. Department of Public Health that the Massachusetts Constitution does not allow the denial of marriage licenses to same-sex couples.
First rise May–October 2008: The supreme courts of California and Connecticut make similar decisions based on their states' constitutions.
Drop November 2008: The voters of California overturn their supreme court's decision by constitutional amendment on Proposition 8 . California is the most populous state in the Union, hence the large size of the drop here.
Second rise 2009–2010: Iowa, Vermont, New Hampshire, and the District of Columbia legalize same-sex marriage, the first by state supreme court decision, and the latter three by legislative action.
First acceleration 2011–2012: New York legalizes same-sex marriage by legislative action. Washington State, Maine, and Maryland do so by voter referendum.
Second acceleration 2013–2014: The U.S. Supreme Court's decision in Hollingsworth v. Perry re-legalizes same-sex marriage in California. Seven states legalize it by legislative action or state court decision. The Supreme Court's decision providing federal benefits for same-sex marriages in United States v. Windsor , while not saying that there is a constitutional right to same-sex marriage, is widely cited as precedent by judges who do say so. Oregon and Pennsylvania decline to appeal such decisions, and five states' appeals are declined by circuit courts, and declined to be heard by the Supreme Court.
[A graph with the x-axis showing time in years from 1940 to some time after 2010 (presumably ca. 2014). The y-axis shows percentage of population. The graph has 4 lines, 2 solid and 2 dashed, with 2 different colors: red and blue. The red lines indicate statistics concerning interracial marriage, while the blue indicate statistics concerning same-sex marriage. The solid lines indicate population living in states where that type of marriage is legal, while the dashed lines indicate popular approval of that type of marriage based on various polls.]
[Solid red line:] Percentage of US population living in states with legal interracial marriage [Dot on solid red line:] Full legal access: 1967 [Dashed red line:] Popular approval of interracial marriage (Source: Gallup Polls) [Dot on dashed red line:] Majority approval: 1995 [Dashed blue line:] Popular approval of same-sex marriage (Source: various polls) [Dot on dashed blue line:] Majority approval: 2011 [Solid blue line:] Percentage of US population living in states with legal same-sex marriage
[Interracial marriage is indicated as being more than 50% legal in 1940, with a very slight downward trend that spikes up slightly ca. 1948, then trends slowly upward to about 65% until ca. 1967, at which point it spikes directly to 100% legality and remains there through 2014. Popular approval of interracial marriage is below 10% in the late 1950s, rising steadily to approximately 40% in 1980, then continuing to rise more slowly to the majority approval point in 1995, and spiking up to about 65% ca. 1997, plateauing until ca. 2003, rising quickly again to about 75% ca. 2006 and rising generally upward to the final ca. 2014 statistic depicted between 85% and 90% popular approval. The visual effect seems to be a wide gap of time between legalization of and popular approval of interracial marriage. Popular approval appears to trail legalization by no less than 20 years at any given point.
Popular approval of same-sex marriage (according to "various polls") is depicted first at about 15% ca. 1986, trending gradually upward until ca. 2000, where it plateaus between 35% and 40% to resume an upward trend ca. 2007, continuing steadily through majority approval in 2011 to a ca. 2014 value between 55% and 60%. The legality of same-sex marriage is indicated to start at 0% ca. 2002, then jumps quickly to plateau around 5% until ca. 2008, at which point it spikes up to between 15% and 20%, then plummets to just above than 5% by ca. 2009, jumping quickly back up to between 15% and 20% between ca. 2010 and 2011, then trending upward even more quickly to end at about 55% legality ca. 2014. The visual effect seems to be a more turbulent line for legality of same-sex marriage than any of the other trends, which also seems to be quickly closing on the popular approval trend. Popular approval has preceded legalization by nearly 20 years at certain points, but the trends appear to be closing and may intersect by 2015 or 2016.]


The Sake of Argument

Explanation:
Ponytail is trying to get Cueball to consider a hypothetical situation, for the sake of argument. It appears that Cueball is questioning the wisdom of doing so, and postulating that assuming unreal hypotheses for the sake of argument is a stupid thing to do, because it causes more arguments. Ponytail then claims she is playing the Devil's advocate, and Cueball again lambastes her for advocating for somebody as unsympathetic as the Devil.
In a debate or discussion, to play the Devil's advocate is to take a position with which you do not necessarily agree (and typically which no one involved in the argument agrees) to allow further exploration of the subject. As the title text starts to explain, it can be a device used to explore a different viewpoint to gain a wider understanding. Arguing for a view with which you do not agree can provoke a re-evaluation, or conversely a re-affirmation of your previously held view by considering the merits of the potential counter-argument. To be able to play the Devil's advocate convincingly is the mark of a well-rounded debater.
However, Cueball interprets her statement literally, thus assuming she is arguing on the side of the Devil , the religious entity defined as pure evil. Obviously, it would be ill advised to take his side during a debate [ citation needed ] .
Cueball then pulls an ironic twist on Ponytail by revealing that he was questioning Ponytail's argumentative style for the sake of argument himself. The comic actually plays on the double meaning of "argument": Ponytail refers to a statement in a debate while Cueball suggests a quarrel in the last panel.
In the title text, an exasperated Ponytail is trying to explain to Cueball that she is trying to use these debating techniques as a device to explore and broaden her understanding of her reality or a plausible alternative. Cueball derails the conversation, by comparing these attributes to a boat, which also allows you to explore other areas and broaden your experiences and understanding (as mentioned earlier in 209: Kayak ). Ponytail is rendered speechless by this statement, and Cueball further suggests that they should get a boat, and that Ponytail can bring the Devil too.
[Ponytail and Cueball are talking.] Ponytail: Just for the sake of argument, let's say that— Cueball: —wait, for the sake of what? [Panel zooms to only show Cueball.] Ponytail: Argument. Cueball: Ok, cool, that's totally a good reason to say something that's wrong. Gotta have arguments. [Panel returns to original view.] Ponytail: I'm just playing Devil's advocate. Cueball: Ok. So you saw an argument where one side was the Devil , and you were like "Man, that guy could use an advocate." Ponytail: It's... why are you being so difficult? Cueball: For the sake of argument. Ponytail: Argh! Cueball: Yay, it's working!


Lightsaber

Explanation:
This comic references a scene from the third theatrically-released Star Wars movie, Return of the Jedi , wherein Darth Vader confronts his son, Luke Skywalker , who had recently surrendered to Imperial soldiers. In the movie, Vader notes that Luke has constructed a new lightsaber following the loss of his original during their duel on Cloud City (Luke Skywalker's original lightsaber actually having been Anakin Skywalker's second).
Lightsabers are often jokingly referred to as "laser swords" by fans (note that the official French-language translation of Star Wars actually calls them "laser sabers"), and this comic points out that a real laser would not have any way of stopping and would therefore continue forever, making this particular interpretation silly. (The Star Wars writers cleverly fail to state what exactly a lightsaber's blade is made out of, although this point makes it unlikely to be a laser.) Once Darth Vader turns on the light saber, it goes offscreen and presumably continues in that direction forever, causing much mayhem as it blazes through the stars. Hull breaches are a popular trope in science-fiction, despite curiously being almost entirely absent from the Star Wars films.
The title text refers to GRB 080319B , an unusual gamma ray burst in 2008, the afterglow of which was briefly visible to the human eye. It implies that the source of this burst was a light saber in the Star Wars story, which took place "a long time ago in a galaxy far, far away" according to the Star Wars opening crawl .
Luke Skywalker and Darth Vader have had a similar conversation before in 1397: Luke . In that version Luke wishes for Vader not to turn it on, as stated in the title text. He should probably have said this here in this comic!
[Luke Skywalker and Darth Vader are talking. Vader holds the handle of a powered-off lightsaber.] Vader: I see you have constructed a new lightsaber. [Vader turns it on. The beam of the lightsaber continues upward out of the frame.] Lightsaber: Snap-Hisss [Vader looks up toward where the beam is pointing.] [Vader looks back at Luke.] Vader: Where does it end? Luke: Doesn't. Intercom (out of view): Hull breach all along sector five!!


Where Do Birds Go

Explanation:
Cueball searches Google to find out where birds go when it rains. He finds that the question is asked worldwide, across many different languages and websites. A variety of screenshots are shown of different websites and forums where users have asked where birds go when it rains, with at least nine languages shown. The bottom of this panel fades to white, suggesting that the occurrence of these questions stretches on and on. Cueball expresses delight at the idea that this question is the one to which everyone wants to know the answer; worrying about birds getting wet is "the thing that unites us".
Later in the comic, a bird in the rain is also searching on the Internet for where birds go when it rains. This is humorously implying that a significant set of these questions are being typed by birds looking for a dry place after being caught in the rain, and not humans. This would make Cueball wrong; worrying about birds getting wet would not unite us. In reality, as the comic states, birds look for shelter so they can stay dry. On a rainy day you can usually find birds in leafy trees, caves or other kinds of cover.
In the Superman comics, Clark Kent is Superman, so you never observe both Clark Kent and Superman simultaneously. By analogy, the title text whimsically suggests that a possible inference from the observation that you never see birds and rain together is that birds are the rain. Perhaps birds are an unknown phase of water. In addition to its familiar phases of ice , vapor , and liquid water , water has more exotic phases such as low-temperature and high-pressure ices and supercritical gases ; why not birds?
The title text imbues the question with more philosophical significance than it warrants (prompted, perhaps, by Cueball's earlier hyperbole), and points up the irrationality of the implication that a question must be deep simply because a lot of people ask it, and that such questions demand a complex, radical answer.
Where do the birds go when it rains? ( archive )
[...] Where do birds go when it rains or storms? ( archive )
Where do Birds go When it Rains? ( archive )
Where do birds go when it rains really hard?
Where do the birds go when it rains?
Où se cachent les oiseaux quand il pleut? ( archive ) (Translation: Where do the birds hide themselves when it rains?)
was passiert jetzt eigentlich mit den vögeln, die bei dem wetter in den bäumen sitzen? [1] ( archive ) (Translation: What actually happens with the birds that are sitting in the trees in this weather?)
Was machen Vögel bei schlechtem Wetter? ( archive ) (Translation: What do birds do in bad weather?)
Wohin gehen Vögel? ( archive ) (Translation: Where do birds go?)
¿Qué pasa con las aves durante un huracán? ( archive ) (Translation: What happens to the birds during a hurricane?)
¿A donde se van los pajaritos cuando llueve? [2] ( archive ) (Translation: Where do the little birds go when it rains?)
Waar blijven de vogels als het heel hard stormt? (Translation: Where do birds stay when it is storming very hard?)
Minne linnut menevät sateella (Translation: Where do the birds go when it rains?)
下雨时鸟儿往哪躲 (Translation: When it rains, where do birds go to hide?)
下雨的时候小鸟住在哪里 (Translation: When it rains, where do the birds go?)
为什么鸟儿下雨的时候在天上飞不会因为淋湿掉下来? (Translation: When it rains, why do birds not fall down from getting soaked?)
【雑学】暴風雨の時、鳥はどこに避難してるの？ ( archive ) (Translation:【Miscellaneous Knowledge】Where do birds take shelter during a rainstorm?)
Burung Dapat Bertahan Terbang Berapa Lama Disaat Hujan ? ( archive ) (Translation: How Long Can Birds Survive Flying In the Rain ?)
[Cueball is sitting at his desk with his computer.] Cueball: "Where do birds go when it rains?" is my new favorite Google search. Megan (off-screen): Why?
[Megan enters the frame.] Cueball: It gives the answer, but also shows you an endless torrent of other people asking the same question. Cueball: Pages and pages of them, across regions and cultures.
[The panel now only contains a Google search on the computer.] Cueball (off-screen): I love the idea that somehow this is the universal question, the thing that unites us. Cueball (off-screen): When it rains, we wonder where the birds go, Cueball (off-screen): and hope they're staying dry.

[A collage of screen snippets.]
from Yahoo! Answers : Where do the birds go when it rains? I've noticed I rarely see birds flying around or in trees or on power lines when it's raining, So where do they go?
from Godlike Productions : Where do birds go when it rains really hard?
Ok, maybe I'm an idiot for asking this, but during the slew of several storms in California the last couple weeks, I began to wonder where the poor birds go to stay dry? The ducks, seagulls, owls, sparrows, hummingbirds, hawks, etc...I see them all the ti[...]
from Random Thoughts From Midlife : Where do the birds go when it rains?
from Answers.com : Where do birds go when it rains?
from Yahoo! Respuestas : ¿A donde se van los pajaritos cuando llueve?
from Active Rain : Where do Birds go When it Rains? I'm no youngster...and I have no answer for this. I've talked to alot of people about the likelihood of where birds go when it rains and everyone has a different perspective.
from Ask MetaFilter : Where do the birds go when it rains? BirdFeederFilter: When it's gloomy and rainy, I don't see any birds at my birdfeeder for days on end. Then as soon as it's sunny, they're all over the place. What gives? What do they do on rainy days, just forage near their nest?
from Snippets : Where do city birds go when it rains?
from http://wenwen.sogou.com/ : 下雨时鸟儿往哪躲
没有大树,没有屋檐,怎么办
from eNature.com : Storm shelter In Florida, where I live, we get many thunderstorms, but I never see the birds in trees during the storms. We recently had a tropical storm and I did not see any birds in the trees. Where do birds go when it rains or storms? Just like at night, birds will seek shelter during storms. I remember watching a flock of American robins dive into[...]
from Yahoo! Answers : When it is raining heavily, where do the birds go...i don't see them on the trees, where do they take shelter?
from Yahoo! Questions Réponses : Où se cachent les oiseaux quand il pleut? De ma fenêtre, je n'en aperçois plus un!!!...Les pies semblent avoir abandonné leurs nids...
from gutefrage.net : was passiert jetzt eigentlich mit den vögeln, die bei dem wetter in den bäumen sitzen? bei uns regnet es heftig und der orkanartige wind wechelst ständig richtung und geschwindigkeit. können sich die vögel da in den bäumen halten? retten sie sich instinktiv vorher irgendwohin, wo sie windgeschützt sind?
from Yahoo! Answers : Where do birds go when it rains? I never see any out...?
from lainformacion.com : ¿Qué pasa con las aves durante un huracán?
from Baidu : 下雨的时候小鸟住在哪里？ 下雨的时候小鸟住在哪里？如果是在春天夏天那还好，有树叶遮挡着，但是到了秋天冬天下雨小鸟住在哪里？还住在在树上搭的窝里吗？不怕冻坏自己和小幼崽吗？如果躲雨那就在哪里躲雨呢？怎么没见过它们躲雨？ 谢谢。
from Fairfax Underground : What do birds do when it rains? Recently I installed a bird feeder outside my bedroom window. It is so wonderful the diversity of our feathered friends that frequent the feeder! I love it. My question that I haven't found an answer to is this: What do the little birdies do when it rains? I mean, do they stay put in the trees that they find themselves in,
from a blog on vuodatus.net : Minne linnut menevät sateella? Tänään satoi rankasti. Kuljin metsän halki. Kuulin linnun laulavan. Yksinäinen, mutta itsenäinen ja vahva, tulkitseva ääni. Kaunis. Minne linnut menevät sateella? En ole koskaan nähnyt lintuja rankkasateessa. Luulen, että ne yrittävät löytää suojan. Kuusien ja mäntyjen oksistossa on varmaan suojaisaa. Kallioiden koloihin ja pieniin luolastoihin voi ehkä lintukin hiipiä. Rohkeille löytyy pihoilta suojapaikkoja. Ehkä linnulla oli oma pesäkolo. Siellä oli lämmintä ja kuivaa. Sieltä saattoi rauhassa katsella sateen vierailua metsässä. Siellä saattoi jopa iloita sateesta ja laulaa.
from Yahoo! Answers : What do the birds do when it RAINS like crazy? I live in upstate new york and just moved here and there are so many many birds here especially where I live, the other day I saw a broken egg on the ground in the drive way from a [...show more link] Update : I know they get wet btw but was wondering if they did anything extra to [...show more link] Best Answer Well... it depends on the species of bird, for one. Some are more adapted for rain then others.
from Willem Wever : Waar blijven de vogels als het heel hard stormt? Bij hevige stormen zoekt een vogel de beschutting die bij hem past. Er zijn een aantal vogels die met storm wel vliegen. Maar bij een echte hevige storm schuilen [...]
from http://wenwen.sogou.com/ 为什么鸟儿下雨的时候在天上飞不会因为淋湿掉下来? 刚刚下很大的雨,却还看到有几只鸟一直在天上飞.为什么鸟儿下雨的时候在天上飞不会因为淋湿掉下来? 补充 ：有照片的加分
from speed guide forums : Where do birds go when it rains? Do they just sit in their trees as it rains getting drenched? Or do they seek shelter?
from Google books : Where Do All The Birds Go When It Rains? By Misty Hoopman
[Screen snippets begin to noticeably fade to white at this point.]
from vimeo : WHERE DO BIRDS GO WHEN IT RAINS? One young magpie will give its own story. Barring the thunder and heavy rain, all the sounds on this movie are from this one young maggie. Amazing
from Yahoo! Answers : Where do birds go during wind and rain storms? Where do birds go during wind and rain storms?
from Yahoo! Answers : Where do birds go when it rains? I mean, they can't keep dry in their nests...They have to go somewhere.
from Yahoo! Answers : Burung Dapat Bertahan Terbang Berapa Lama Disaat Hujan?
from vogel.info : Was machen Vögel bei schlechtem Wetter? Zunächst mal, was sie nicht machen: Sie verkriechen sich nicht etwa in ihr Nest, denn das Vogelnest dient der Brutpflege, es ist nicht etwa eine Wohnung. Es stellt sich aber ja auch die Frage, was eigentlich unter schlechtem Wetter zu verstehen ist: Es gibt Vögel, die leiden unter zuviel Sonne und[...]
from gutefrage.net : Wohin gehen Vögel? Hallo zusammen! Heute als es so richtige Gewitter gab, hab ich mir überlegt wohin alle Vögel verschwinden. Haben alle Vögel Nester in die sie sich zurückziehen können? [link to view complete question.]
from Yahoo! Answers : Where do birds go when it rains? Well, yesterday it was raining...I was bored so i started staring out the window, and i say a empty birds nest and i was wondering, where do birds go when it rains?
from Diolún Designs Blog : Where do Birds go when it rains or snows?
from The Andalusia Star-News : Where do birds go when it rains? I haven’t fed birds in my back yard for a long time, but I still enjoy the few I see perching on top of poles, an electric wire, tree branches, or scooting across the [...]
from Bird Ecology Study Group (blog) : Where do birds go when it rains? And what do they do then? It has been raining on and off these few weeks and the birds have not been around. Have you ever wondered what happened to them when it
from Naver Matome : 【雑学】暴風雨の時、鳥はどこに避難してるの？ 人間が歩くのも困難な暴風雨。その時、一番影響を受けるのは空を飛んでいる鳥達ですよね。彼らはどのように風雨を凌いでいるのか？ずーっと気になっていた事を調べてみました！
[At this point, at the bottom of the section, screen snippets are extremely faded.]
from The Daily Apple : Apple #431: Birds in the Rain Forgot until late tonight that I meant to make a new post. Since I didn't leave [...]
from Yahoo! answers : Where does birds go when it rains?

[A bird sits on a wire fence.]
[The bird looks around as raindrops fall.]
[The rain becomes heavier.]
[The bird flies down to a phone on the ground.]
[The bird lands on the phone. The rain is getting heavier.]
[The bird pecks on the phone.] W... H... E... R... E...   D... O...   B... I... R... D... S...


Presidential Alert

Explanation:
The Emergency Alert System allows the U.S. President to address the country in the event of a national emergency, by broadcasting a message over all television and radio channels. Despite the system's having existed in various forms for over 60 years, no president has ever used it, even during the September 11 attacks .
In this comic, the US President accidentally activates the system by pressing a button, apparently located on the Resolute Desk in the Oval Office . Surprised by being on television, he tries to think of something important to say on the spot, but cannot think of anything other than a piece of generic dental-hygiene advice – a rather non-urgent message.
An alternative explanation is that he is actually supposed to tell everyone some really bad news, something totally cataclysmic, only to chicken out and try to explain that the alert was a mistake. This version also explains why he begins to speak to the public and then changes his mind.
The concept of the President mistakenly hitting an important button has long been a source for jokes, often somewhat morbidly involving the nuclear football .
The title text references the typical conclusion to presidential speeches: "Goodnight, God bless you, and God bless the United States of America," or some variation thereof. As "goodnight" is the typical conclusion to a day, the title text jokes that President Obama , out of habit, has a hard time stopping at goodnight when saying that to his children.
[Television beeping.] Screen reads: "E.A.S Incoming Presidential Alert"
[Person in an office is on the television.] My fellow Americans. I, uhhh. Wow.
Frankly, I didn't realize what this button did. I was just... I mean... I appear before you tonight to, um.
Look, uhh... Remember to floss regularly. Oral hygiene is important. Thank you.


Orb Hammer

Explanation:
Cueball suggests doing something that sounds absurd and not useful at all for the daily activities of a regular human. Yet it refers in unexpected English words to the Apollo human spaceflight program which, among other things, sent people to the Moon to bring moon rock samples back to Earth to study them (i.e. hitting the glowing orb in the night sky with a hammer until little pieces break off). Although you might think that moon rocks would be prized as unique scientific samples, in actual fact many of them were stolen or simply lost . Many were given as gifts to politicians from US states and foreign countries , who then kept them, sold them or had them stolen - two-thirds of these moon rocks are missing and presumably locked up in a cupboard, display cabinet or warehouse somewhere. The rest are kept in museums or laboratory store rooms, where they usually stay untouched except for the occasional removal of samples.
The use of such language contributes to the effect of the suggestion sounding absurd. Of course, numerous results of the Apollo program have in fact had many benefits for regular people.
No person has been on the Moon since the final Apollo mission, Apollo 17, in 1972. Occasional lunar rocks can still be collected on Earth. They are formed when a celestial body impacts the Moon's surface, forming a crater and launching small rocks into the space. Some of them will eventually reach Earth, see lunar meteorites .
The title text refers to various robotic missions, including the current Mars missions ( Pathfinder , Spirit , Opportunity , Curiosity ) as well as to the Philae lander component of the Rosetta mission (with details of its intended landing site confirmed a mere handful of days before the comic).
With robots, instead of traveling to Mars ourselves, we stay on Earth ("our regular orb") and program and direct rovers to operate remotely. Hence the rovers are described as hammers that hold themselves. The rovers collect geological samples and analyze them on site, but have no way to send the samples back to Earth. This is why the title text ask to make sure to get lots of pieces of rock because it seems we will not go that far in to space today or any time soon.
The idea of using simple language in highly technical fields began with 547: Simple and was revisited in 722: Computer Problems , 1133: Up Goer Five , and 1322: Winter . It should be noted however, that in this case Randall didn't use the 1000 most basic words in the English language, because the Simple English Wikipedia 's List of 1000 basic words does not contain the words "glowing" or "orb," but does contain "moon," "earth," "bright," and "ball."
The idea of using unexpected language to create humor highlighting the absurdity of normal activities has previously been explored with 203: Hallucinations .
[Cueball talks to another Cueball-like guy:] Cueball: You know that glowing orb in the night sky? Guy: Yeah? Cueball: Let's go hit it with a hammer until little pieces break off, then bring the pieces back and lock them in a closet. Guy: Sounds good!
[Caption below the frame:] The Apollo program was weird .


Higgs Boson

Explanation:
Cueball and Ponytail are applying for a large amount of grant money to find the Higgs boson . Under scrutiny, they have been forced to admit that they have "lost" the particle which had been previously "found". This is a humorous play on the term "finding" when applied to fundamental particles. The common usage means to discover or observe the existence of a class of particles, rather than to know the current location of an individual particle.
The Higgs boson is an elementary particle that is predicted by a physical model of the universe (the ' Standard Model '). Observing evidence that Higgs bosons really exist is a key test of this model: if a search for the Higgs boson had failed to find evidence confirming its existence then the Standard Model would have been shown to be an incorrect description of reality. Finding the Higgs boson was one of the main reasons why the Large Hadron Collider (LHC) was built: to create energies high enough for the Higgs boson to become manifest. The point is, once evidence for its existence has been observed it is not possible to 'lose' the Higgs boson in a way implied by Cueball and Ponytail.
In the title text, the off-screen questioner wonders why Cueball and Ponytail can't use the LHC to find the particle again. The implication is that this would avoid spending another $3 billion. Their responses imply that the pair have already dismantled the LHC and converted its components into a death ray (most likely a particle-beam weapon to be exact). The ostensibly reassuring platitudes offered mimic those used to placate those who were worried about possible apocalyptic consequences of commissioning the LHC, for instance the creation of black holes , strange matter , a vacuum bubble or proton-eating magnetic monopoles .
The comment that "The death isn't even very serious" in the title text may be a reference to Isaac Asimov's "I, Robot." Robopsychologist Dr. Susan Calvin tells supercomputer The Brain not to worry about death, that it wasn't a "big deal," when the robot is working on an equation relating to hyper drive. The Brain was able to deliver the solution, since anyone using the hyperdrive would be briefly "dead" (no longer exist), but in the end, they would arrive safe and sound.
This also implies that the death ray was only able to produce one death, as opposed to the many deaths such a weapon could be expected to cause, just as it is implied that the LHC only produced a single Higgs boson, which was subsequently misplaced. In 401: Large Hadron Collider the proton stream from the LHC was used to give a helicopter cancer.
Offscreen: Tell us about your proposal. Ponytail: We're requesting $3 billion in funding to find the Higgs boson.
Offscreen: ...wait. Didn't you already find it a year or two ago? Cueball: Yes, well, um.
Ponytail: ...OK, this is embarrassing. Cueball: See, the thing is—
Offscreen: Don't tell us you lost it already. Ponytail: Look. Ponytail: In our defense, it's really small.


Houston

Explanation:
This comic presents a joke: a Cueball is at Mission Control, but is failing to help a damaged spacecraft, and is, in fact, being rather unhelpful and completely ignoring them. This is contrary to how one would expect mission control to behave in the event of an explosion. [ citation needed ]
Alternatively, this could be some type of commentary:
Or Cueball is just named "Houston".
On Apollo 13 's way to the Moon, during a routine stirring of one of the oxygen tanks, an explosion occurred that damaged the craft. Frantic efforts by the mission control center located in Houston resulted in the safe return of all astronauts.
A similar situation is depicted in this strip including the design of the spacecraft, the nature of the problem, and the famous misquote "Houston, we have a problem". The modern type of monitor ( flat panel LCD ) in front of which Cueball sits suggests that the author is describing a more modern scenario. This time there is much less help from mission control. Upon receiving the message from the spacecraft, Cueball seems fairly indifferent. Instead of attempting to resolve the issue, he mocks the crew for not knowing how to stir and hangs up in favor of taking a call.
In the title text we learn that the call was from Cueball's mother, which should be far less important than helping the crew return safely. He also tells her that he's doing "nothing important"—further driving home how little he cares about them.
NASA mission Apollo 13 was intended to be the third manned landing on the moon. Immediately following the explosion, astronaut Jack Swigert calmly reported—and shortly later repeated by James A. Lovell—to mission control: "Houston, we've had a problem"—a notable understatement which was famously misquoted in the 1995 film adaptation of the mission as "Houston, we have a problem".
Mission control worked diligently and tirelessly to solve numerous problems such as:
[A spacecraft floats in outer space, the earth far in the background. Bits of it have broken off.] Orbiter transmission: Houston, we have a problem
[Cueball with a headset sits at a computer desk with two monitors.] Cueball: Cool.
[We see a close-up of Cueball.] Orbiter transmission: ...What? Houston, we stirred our O₂ tank and it exploded ! Cueball: Sounds like you suck at stirring.
[We see the orbiter in space, far from the planet.] Orbiter transmission: ...Houston? Are you- Cueball: Listen, I've got another call. Good luck landing your airplane or whatever. Click


Rack Unit

Explanation:
Black Hat announces to Megan that 19-inch racks for datacenter servers and Langstroth hive frames are both 19 inches wide (482.6 mm), with similar spacing between each slot. Black Hat is motivated by this knowledge to break into a Google datacenter and fill server racks with beehives. He then announces that Google led the world in datacenter honey production, an accomplishment fairly easy to achieve as no other datacenters are producing honey [ citation needed ] . Obviously, such an action led to Black Hat being kicked out from the facility by security guards and the loss of his hives. When Megan sarcastically consoles Black Hat for the loss of his hives, he declares that he'll find other datacenters to install hives in.
The pitch (or distance between repeating items) of 19 inch rack server hardware is measured in rack units (U) , and is standardized at 1.75" (44.45 mm). Langstroth frames are typically mounted at a pitch of 1.5" (38.1 mm) , and as a result would fit relatively well with a server cabinet. In contrast to the horizontal orientation of the modules in a server rack, honeycomb frames are designed to hang vertically, so the cells can hold nectar without it dripping out. How Black Hat was able to re-orient the racks to suit the needs of honey production remains a mystery.
Some datacenters provide colocation services where customers may install a server at a central location with better bandwidth and power reliability than a customer could provide on their own. Noticing that typical colocation terms of service (TOS) agreements don't specifically rule out the installation of beehives, Black Hat suggests he can enter a legal contract allowing him to install beehives at a data center without being kicked out. This, of course, is because nobody had previously thought that such a rule was necessary. Megan expects this to change once Black Hat starts deliberately exploiting this oversight.
The title text is a reference to the film Air Bud . The original quote is "Ain't no rules says a dog can't play basketball." Much like Black Hat's beehive plan, the plot of Air Bud relies on a plan being so outlandish that nobody has ever thought to specifically forbid it before.
[Megan and Black Hat are talking, Megan is sitting at a computer.] Black Hat: I've discovered something. Megan: Oh? Black Hat: Standard server rack units and standard beehive honeycomb frames are compatible. Black Hat: They're both 19 inches, with similar pitches. Megan: Uh oh. Black Hat: I'm pleased to announce that today, for a few hours, Google led the world in datacenter honey production. Black Hat: Until their security people kicked me out. Megan: I'm sorry your beekeeping career ended so quickly. Black Hat: I'll find a new datacenter. Black Hat: Turns out most colocation TOSes don't mention beehives. Megan: I suspect that will soon change.


Geese

Explanation:
Megan is commenting on a flock of geese passing overhead and says the light from the geese reaching their eyes now could have come from hundreds of years ago. This is a fact for the light from stars, but not for light from geese [ citation needed ] . Cueball points out the absurdity of Megan's statement by pointing out that the geese are only a few hundred yards away rather than a few hundred light years. She continues along the same lines when she implies to Cueball that he is observing a past version of her, despite them being only a few feet apart. Technically he is viewing a past version of her, but not one from "long ago"; if someone is two feet away from you, you are seeing them as they were roughly 2 nanoseconds ago.
In the title-text Megan continues to treat the geese as if they were stars, which "live" for a few billion years before exploding. Most stars visible with naked eye are within a thousand light-years of Earth, (as discussed in 1342: Ancient Stars ), and it's unlikely that any star Megan currently sees actually exploded within the relatively short span of last few thousand years.
Megan's statement "You're hearing how they once sounded." is somewhat more justified - sound from "a few hundred yards away" would take about one second to be heard (depending on the exact distance and the prevailing atmospheric conditions). That said, the sound of a goose isn't likely to change enough over the course of a second or two to make this distinction particularly significant.
The strip may also take inspiration from Gamow's "Mr. Tompkins" stories which were designed to help laymen understand some of the consequences of relativity and quantum mechanics. In one of the stories Mr Tompkins visits a town where the speed of light is 30 miles per hour. For the light to have taken hundreds of years to go from the geese to Megan and Cueball, the speed of light in this strip would have to be much slower than in Gamow's story.
Randall has previously mentioned a related misconception in 1342: Ancient Stars . In 1422: My Phone is Dying , a phone's "death" is compared to the death of a star.
[Geese fly in V-formation. Megan and Cueball are lying on the ground, watching them.] Megan: To think... we're seeing light that left those geese centuries ago. Megan: By now, they could be long dead. Cueball: ...What? They're a few hundred yards away. I hear them honking. Megan: Ah, yes. You're hearing how they once sounded. Cueball: You're very weird. Megan: Or I was, long ago...


Turnabout

Explanation:
In the comic, two people are engaging in a battle with laser guns. One appears to gain the upper hand as he jumps on an obstacle, as the other's shot goes wide. He delivers the classic line "Any last words?" and is answered with the confusing phrase "Apollo retroreflectors". The earlier wild shot, reflected off the Moon, promptly lances down from space and hits him in the back.
A retroreflector is a device or surface that reflects light back towards its source. Several such devices were placed on the Moon during the Apollo missions and have been used ever since by scientists on Earth to measure the distance between the two bodies using laser ranging . Retroreflectors were placed by the American Apollo 11 , 14 , and 15 missions. The Soviet Lunokhod 1 and 2 rovers also carried such reflectors; attempts to use them for laser ranging were unsuccessful from 1971 to 2010, but were successfully renewed after the rovers' positions were photographed by the Lunar Reconnaissance Orbiter .
The title text may be a reference to the common practice of "calling bank" in the game of basketball. In basketball, the backboard may be used to deflect the ball into the hoop. This is called a "bank shot." In casual games, if the player using the backboard in this way does not indicate that it was intentional by "calling bank" before releasing the ball, the basket may not be counted in order to not give the player credit for a wild shot that happened to go in. When a player releases a shot that they realize is off the mark they sometimes quickly say "bank" to try and fool the other players into thinking that they were intentionally trying to "bank" the ball off the backboard into the hoop. In the title text scenario, "Apollo retroreflector" is used the same way "bank" is in basketball, i.e., the shooter meant to hit the target by reflection rather than directly.
Randall discussed the effect of hitting the Moon with lasers in What If: Laser Pointer and the likelihood of hitting a celestial object with a laser in What If: Into the Blue .
The likelihood of the wild shot being aimed at the Moon is fairly low in itself, and the probability of accidentally hitting a retroreflector on the Moon is lower still. Even if it did, it is highly unlikely that a pistol-sized generator could produce a beam coherent enough to inflict damage after traveling to the Moon and back, as lasers built for the purpose of hitting retroreflectors on the Moon typically get a return around one quadrillionth of the original beam, and a visible light laser would need a very large lens or mirror in order to still be relatively concentrated upon hitting the reflectors.
[A guy and Cueball are engaged in a fight with laser pistols. The guy is standing behind a small box, firing his gun at Cueball.] [Cueball is kneeling behind a larger box, returning fire.] [The guy leaps on top of the larger box, knocking Cueball backwards and off balance. Cueball fires wildly into the air.] [Now the guy is standing on the box. Cueball is sprawled on the ground, laser pistol out of reach, at gunpoint.]
Guy: Any last words? Cueball: "Apollo retroreflectors." Guy: What?
[The guy gets shot in the back by the returning beam of Cueball's wild shot.]


Chemistry

Explanation:
This comic is a classic example of taking an absurd premise, and applying correct science to it, to see how different the conclusion is to the real world.
The idea of Typographic Chemistry presented in this comic is a play on  Douglas Hofstadter ’s Typographical Number Theory and Typographical Genetics , which are featured in Gödel, Escher, Bach . While Hofstadter's typographical systems are designed to model aspects of real genetics and number theory, Randall abuses this notion by inventing a typographical system which bears no resemblance to real chemistry.
Chemical bonding is a well-known subject which explains the formation of molecules from atoms . This comic refers to three chemical elements : carbon (C), hydrogen (H), and oxygen (O). In real chemistry, the formation of bonds between atoms depends on the number of valence electrons each atom has, and how accessible those electrons are for bonding. The comic jokingly replaces valence electron theory with a theory that the number of bonds an atom can form depends on the number of leaf vertices possessed by the chemical symbol's letter. A leaf vertex is a vertex having only one edge connecting to one other vertex. "H" for example, the chemical symbol of hydrogen, has 4 leaf vertices. This is shown in the comic by the four half-circles placed at each leaf vertex of the "H". Thus, in the comic's theory, elemental hydrogen can form 4 bonds. Oxygen, however, having the chemical symbol "O", has no leaf vertices, and according to the comic's theory should not bond to anything, and is therefore inert.
Of course, the theory is completely inconsistent with observed chemistry. While the comic declares oxygen is inert and forms no bonds, this is not really the case: the two unpaired valence electrons in a lone oxygen atom make oxygen reactive, and oxygen atoms readily form molecules. Diatomic oxygen, O 2 , makes up about 20.9% of Earth's atmosphere, and is essential for aerobic life, including human life. Similarly, a water molecule consists of an oxygen atom tightly bonded to two hydrogen atoms.
By observing real chemical compounds, chemists have deduced that hydrogen atoms really have 1 valence electron, carbon 4 and oxygen 6, allowing hydrogen to have up to 1 bond, carbon up to 4, and oxygen up to 2. Thus carbon can have up to four bonds, and really is often found in crystalline form in nature (diamonds and coal are allotropes of carbon); oxygen can have up to 2 bonds, and can combine with carbon to form CO 2 (instead of C 2 H in the comic). Randall thus gives to "typographic" hydrogen qualities that belong in real-life to carbon, since "typographic" hydrogen can have 4 bonds. Similarly, "typographic" carbon is ascribed properties belonging to real-life oxygen. "Typographic" oxygen takes on the properties of the real-life noble gases (like helium, neon, and argon), which form no bonds and are inert.
While the ethynyl radical , which has the structure ∙C≡C–H, does have the formula C 2 H, there is no molecule with the C–H–C structure in nature. The word "mydrane" is a whimsical neologism for this fictional substance: the "hydr-" prefix for hydrogen is changed to "mydr-" (a prefix which does not exist) and combined to the "-ane" suffix for alkanes (simple hydrocarbon molecules). Perhaps Randall named this compound "mydrane" to declare ownership of it ("my-" as in "mine"). Another reasonable assumption is that the word is a portmanteau of methyl (Me- is the prefix for 1 carbon chains attached to a functional group) and hydrogen with the -ane suffix for alkanes; the nomenclature stems from (di-)m(ethyl) (h)ydr(ogen) -ane, which would form mydrane. Technically, the nomenclature would be "dimethyl" since there are two "methyl" groups attached to the functional group (i.e. hydrogen in this case). It would, however, not be uncommon to drop a di- from a compound name if it's redundant (only one possible compound, e.g. dimethyl ether which sometimes is referred to as methyl ether) or makes a clumsy name ("dimydrane" could make it sound as if there are two mydrane groups).
The title text points out that the theory as presented only applies to sans-serif text. A serif is a small line across the end of each stroke. " H ", for instance, has four serifs, each with two leaf vertices. Thus hydrogen in a serif font would be able to form 8 bonds making it, according to the comic's theory, "more reactive".
[A large capital letter "H", with faint gray circles drawn on the ends of each of the four legs.] Hydrogen can form four bonds. It readily bonds with itself, and often exists as a crystal. [A lattice of several H's, all "bonded" together at the ends of their legs in a crisscross, meshlike pattern, labeled:] Crystalline hydrogen
[A large capital letter "C", with faint gray circles drawn on both ends of the arc.] Carbon can only form two bonds. It readily bonds with hydrogen to form C 2 H (mydrane) or itself. [Image of a C and an inverted C, linked at their endpoints, labeled:] C 2 [Image of two C's linked with an H between them, labeled:] C 2 H
[A large capital letter "O".] Oxygen is inert, forming no bonds... [Image of several lone O's, none connected to anything, labeled:] Monatomic oxygen gas.
[Caption at bottom:] Typographic chemistry


Language Nerd

Explanation:
Parts of speech can be treated fluidly, in English and other languages. For example, "medalled" has been coined as a word meaning "gained a medal" in a sporting competition, implying the existence of the verb "to medal" meaning "to win a medal". This is a literary trope called anthimeria, and is typically used by using a noun as a verb (or 'verbing a noun'). Megan , in conversation with Cueball , similarly creates new meanings from existing words: firstly, she uses the adjective "legit" (a slang abbreviation of "legitimate") as an adverb to mean "legitimately"; secondly, she uses the noun "adverb" as a verb meaning "to turn a non-adverb into an adverb"; and thirdly, she uses the noun phrase "language nerd" as an adjective. All three are used in the past tense.
Megan uses the words "verbed" and "adjectived" without any comment, implying that the acts of "verbing" the nouns "verb" and "adjective" are so natural and long-established that they are unremarkable (although the fact that "adjectived" came after "verbed" may also have something to do with the latter's non-mention), even if grammatical purists might decry such usage. An example of a change of parts of speech that is widely accepted is the gerund , which is nothing more than the use of a verb or verb-phrase as a noun; for instance, "I enjoy reading ," and "the best thing for your health is not smoking ".
Added humor is gained by the self-referential nature of Megan's sentence. She uses fluid parts of speech, and also refers to that very same use, in one sentence.
The title text, "Not to go all sentence fragment on you," is an implicitly self-referential sentence fragment, containing neither an explicit subject nor a predicate. It can be converted into a full sentence by rephrasing it something like, "I do not mean to go all sentence fragment on you, but..."  It is also funnier because, as well as being self -referential, it also refers to the main comic by adjectiving the noun-phrase "sentence fragment".
Megan: I don't mean to go all language nerd on you, but I just legit adverbed "legit", verbed "adverb", and adjectived "language nerd".


Cloud

Explanation:
Cueball and Megan are lying outside on the grass and looking up at the clouds. Cueball asks Megan what she thinks a particular cloud looks like, following the common human activity of pareidolia , or spotting apparent patterns where there are none (particularly in clouds).
Rather than responding with her own interpretation, Megan takes a picture of the cloud with her phone, and uses Google's Search by Image feature. In this feature, the user uploads an image rather than providing a keyword to search on, and is presented with suggestions about the subject of the original image. Google's search results reveal that the image Megan uploaded is most probably a photograph of a cloud. [ citation needed ] While indisputable, this does not address the fanciful dimension of Cueball's original question, and highlights the continuing limitations of artificial intelligence with respect to human imagination. (Then again, there is not anything tailored to this on image search.)
Google image search works by creating a mathematical model of the shapes and colors in the uploaded image, and matching this against images already in its index. Web page analysis then allows Google to guess at what the image is, based on the content of the pages where the matching images were found. Although apparently unimaginative, even humorously so, [ citation needed ] Google image search does recognize that the subject of Megan's photograph is a cloud, which is an achievement that has so far eluded programmers. This was the subject of 1425: Tasks .
If the term "cloud computing" is taken entirely literally, and purely in the context of this comic, then the title text merely comments that the processing of an image of a cloud for queries is not at an advanced state yet. It is really, however, a pun on cloud computing , which is a trendy term for the modern tendency of providing massive amounts of digital storage and distributed computing power over the Internet. In this context, the term "cloud" is a metaphor for the way the details of where or how the storage or processing is done are obscured from the user, as if it all takes place inside a cloud. In 2014, cloud computing as a commonly accessible service really is in its relative infancy, being a 21st-century phenomenon, although the concept goes back decades. Java was originally marketed in the 1990s by Sun Microsystems with the slogan "the network is the computer", and the mantra of technologies for distributed computing such as CORBA , EJB and SOAP was "data first" and "the computer is the network".
In a way, every conceivable sense of the term cloud computing is utilized in Google's image search for Megan's cloud image. Cloud computing is also referenced in 908: The Cloud and 1117: My Sky .
It might be interesting to note that the month before, in September 2014, Google employees had published work on image recognition and pattern-enhancing algorithms. Originally conceived to allow better enlargements of small pictures and the objects contained in them, the process could be tweaked to overemphasize weak structures in pictures, leading to DeepDream images, which literally did start to "see" distinct, known structures (mostly dogs) even in random noise. This is rather similar to the pastime of looking for known objects in clouds.
Cueball and Megan are again seen cloudwatching in 1899: Ears .
[Cueball and Megan are lying outside on their backs.] Cueball: What do you think that cloud looks like?
[Megan takes a photo of the cloud with her smart phone.] Phone: Snap
[Cueball sits up and looks at Megan. Megan types the text below into her phone. When the picture is uploading this part is actually is written in square brackets in the comic...] Google -> Search by image [Uploading...]
[In the last frame she gets a response from Google.] Google: Best guess for this image: Cloud Cueball: Keep trying, Google.


Efficiency

Explanation:
There are often multiple ways in which to deal with a problem or task. There may be a most efficient method, though sometimes the differences in efficiency between methods is only slight. People often try to save unnecessary work by first determining which is the "best" method - either the easiest or the most efficient. This can be a good approach, particularly where the savings prove to be significant. But it can also prove to be more time-consuming than just doing the task using one of the most obvious methods. The comic humorously exaggerates this.
One method of trying to determine the best way of performing a task is to perform A/B testing where a trial is performed where the two strategies, A and B, are implemented and compared. Often the two strategies are simple to implement (for instance, two versions of a web page with different text and colours to determine which provides the better rate of click through) and therefore the amount of time required to implement the strategies (the "time cost") could easily be considerably less than the time to determine if the results are statistically significant.
The title text references a supposed incident in which Randall did not commence writing a research paper because he spent the entire assignment period deciding whether to learn an entirely different keyboard layout just to potentially be slightly more efficient in his typing speed. It refers to the Dvorak keyboard layout, an alternative to the most commonly accepted QWERTY layout. Some believe the Dvorak keyboard offers greater typing efficiency. Efficiency of the Dvorak keyboard layout was mentioned in the title text of 561: Well , where it was stated that it was not more effective, and by now it has become a recurrent theme on xkcd.
Other comics about spending too many resources on decisions that ultimately might not matter include 309: Shopping Teams and 1801: Decision Paralysis . Several other comics address similarly wasted time due to bad time management; see for instance 1205: Is It Worth the Time? or the Time management category .
[A bar chart is shown below its title:] Time Cost
[The chart consist of a dividing line, with three labels to the left, and the three black bars to the right. The first two bars are short, the second slightly longer than the first. The last bar is much longer, about 13 time as long as the first shortest bar.] Strategy A Strategy B Analyzing whether strategy A or B is more efficient
[Caption below the panel:] The reason I am so inefficient


Landing

Explanation:
This comic changed over time during 12 hours and 15 minutes starting at 0:00 EST (when the comic normally is released) posting 143 pictures that tracked the progress of the Philae lander separating from the European Space Agency 's Rosetta probe to land on comet 67P/Churyumov–Gerasimenko . More info can be found here: rosetta.esa.int .
The comic presents the imagined anthropomorphic "thoughts" of the Rosetta spacecraft and the Philae lander (and occasionally other parties) during the hours approaching separation from each other, approach to the comet and finally the apparently successful landing on the comet.
Beginning at 11:05 , the comic includes a "Status Report" in the lower right corner which summarizes the status of various interested parties and accomplishments, beginning with "Rosetta", "Philae lander", "Mission Control", "Comet 67P", and "Have we landed on a comet?". As events occur in the comic, more status summaries are added to keep track of the changes to the situation and the supposed emotions behind them.
In many pictures a whale can be seen on the surface of the comet - often marked with a "?" as are almost all other parts of the unknown surface at this time. There is also drawn a Cueball on the surface also marked with a "?" Both are then at some point marked with a probably not - starting from 12:35 . The whales are also mentioned in the "Status Report" where they for instance may be listed as "calm" or "(probably) not in space". At 16:00 the when the entire Earth goes AAAAAAAAAAA the whales are listed as saying this as well (along with Mission control and U.S. scientists). From this moment "Dolphins and fish" are also mentioned in the report. They are asking if it is the whales that scream. The reference to whales comes from the fact that Philae brought along two harpoons that should have been used to anchor it to the comet. On Earth, harpoons have mainly been used to hunt whales; Randall previously brought up that comparison in 1402: Harpoons , suggesting that Philae was programmed to believe it was sent to kill the comet. It is Philae that "dreams" about whales on the surface of the comet which can be seen in the picture for 13:25 and in the status report.
Some Douglas Adams fans believe these whales and dolphins are references to The Hitchhiker's Guide to the Galaxy and So Long, and Thanks for All the Fish . Whales in space have been appearing in fiction and art since the 1960s. However, with the above-mentioned reasons for whales, dolphins and fish, this seems less and less likely.
At 15:25 Rosetta asks Philea about destroying and levitating rocks via mind control. This is a reference to the Ambition short movie, ESA commitioned to gather public awareness of the Rosetta mission.
Shortly after release from Rosetta ( 10:15 ), Philae calls out 'Spaaaaaaaaaace'; this mimics the Portal 2 'Space core' who, on finally reaching space in the last scenes, gives the same elated cry.
US Scientists presumably wake up at 7:40 EST ( 13:40 UTC) and in the report they now says "Bluuurghhh. What time is it?" to indicate their tiredness. This does not change until 10:25 EST ( 15:25 UTC) so they are slow to wake (2 hours 45 minutes). At this point, they becomes anxious as there are only 10 minutes to landing. This last until there is 15 minutes until news of landing (a reference to the 28 minutes time delay due to the huge distance to the comet). From then on ( 15:50 ) they and the mission control (MC) say "AAAAAAA". They stop this when the news should be there - the NOW ( 16:05 ) - and everybody holds their breath indicated by [...] - also MC. Finally ( 16:25 ) they and MC become proud (along with Earth) when Philae announces I got you a comet. It should have stopped there but as Philae bounced around, they then becomes anxious again 16:40 , and then this changes to nervous 16:45 (switching those emotions with MC). And then suddenly ( 16:50 ) it is no longer US Scientists but just plain Scientists - that are nervous. It stays like this during the last few pictures, although they again become anxious, but when Philae announces I did it , they drink wine as indicated with "[wine]" in the report from the second to last picture ( 17:10 ).
Randall has written "A big thank-you to Emily Lakdawalla for help and advice on this comic" in the xkcd page header for Landing , revealing the possible source of his near real-time data.
At 16:20 the status report had announced a big Yes to the questions "Have we landed on a comet" and "Do harpoons work on comets". According to BBC News , the harpoons did, however, not fire as planned and the lander may have landed, bounced off, and landed again. This would explain the change in "Do harpoons work on comets" to "Don't know" at 16:35 and the change in "Have we landed on a comet?" to "Yes, at least once" at 16:50 . According to The New York Times , radio contact with Philae fluctuated, which would explain the "Anxious", "Nervous", and "Confused" statuses around that time.  In the end the lander did land and whereas the Do harppons work status did not change, so did the have we landed on a comet which changed back to Yes at 17:10 .
The lander bounced three times and ended up in a place where the solar panels where mainly in the shadow. This resulted in the lander shutting down when its own battery ran out of power after only 2–3 days on the ground. This seemed sad, as there was only a small chance that the seasons on the comet would change so that the panels would later receive sun again. However, in the few hours that Philae had on the ground, it still managed to analyze the surface and obtain a lot of useful data - so that part of the mission was still a success already. This all happened after the comic stopped updating.
On June 13, 2015, it was announced that signals had been received on earth indicating that Philae had awoken and that the solar panels were functioning.  Ironically, had Philae landed in a place originally out of shadow, it would have already failed before this time (due to overheating), so it was actually fortunate that it landed as it did and would be able to operate during the time that the comet would be closer to the sun. To celebrate the lander's revival, Randall updated the comic, depicting the lander saying "Hi." on the comet's surface.
The comic title was originally "???" (probably to not give away too early what the comic was about), but changed to "Landing" when Randall came on live at five in the morning EST. At that moment the title text also changed from "..." to "[LIVE]". It was also then that the timestamps' timezone switch. At 5:00 AM (EST) the time stamp in the picture naming scheme switched from EST to UTC as used in ESA's time keeping, resulting in a jump from 04:55 to 10:00 without actually any such delay between the two pictures.
There were however a few pictures with more than 5 minutes of delay (about 11 times five minutes without an update in total during the "live" transmission). The update seemed to have stopped after 137 pictures at 17:15 UTC, 12 hours and 15 minutes after the first picture. (The first picture has number 0, so the last had number 136). But later, sometime after 17:15 UTC, the counter for the last picture was increased to 142 (143 pictures in total), so maybe Randall inserted 6 extra pictures later - however he must then have changed the numbers on the pictures, since the last picture remained the same until mid-June, but with number 142 instead of 136. It is thus now difficult to find out which pictures would have been added later. However, eight pictures were not included in the original table with the Frame by Frame Breakdown below. So it must have been some of those missing pictures that were added later - maybe all of them, as the last three may already have been added before the last picture was released (All 143 pictures are included in the flip-book gif image shown here above). But even 143 pictures at 5 minutes intervals only spans 11 hours and 50 minutes, thus there are still five 5 minute intervals without any picture. See which in the table .
The Rosetta space probe is shown in 1621: Fixion , which explains the Flyby anomaly experienced the first time (of three) the probe got close to Earth.
[This transcript gives only the text of the most recent picture shown in the comic; that which is now shown when clicking to the comic on xkcd. This changed a few times after the live event ended.]
[Showing Philae on a comet.] Time Since Landing: 211 days Philae: Hi! [Status report at the bottom-right corner.] Status report: Rosetta: In space Philae lander: Hi! Mission control: !!!!!!!!!!!!!!!! Scientists: !!!!!!!!!!!!!!!! Have we landed on a comet?: YES. Sun: Warm Comet: Big Philae, where ARE you?: Home
[For the full transcript of all 143 pictures see 1446: Landing/Transcript .]


Meta-Analysis

Explanation:
In the scientific literature, meta-analyses are studies which compare multiple studies on a single topic, with the aim of giving a balanced overview of the known results. Medline , Embase and Cochrane are medical research databases which give access to studies on drug effects or results of other medical procedures.
This comic explores the idea of iterating the process, going from meta-analyses to meta-meta-analyses (which actually exist, though not necessarily by that name, see below) and hence to a meta-meta-meta-analysis.
Of course, the title text adds another level of meta-analysis, since he wants to make a meta-analysis of rejection letters which concern his meta-meta-meta analyses.
All of the cited meta-meta-analyses are real: M. Sampson (2003) , P. L. Royle (2005) , E. Lee (2011) , and A.R. Lemeshow (2005) .
The phrase "too meta" can be found in the comments of videos, blog posts, and other internet content for which the commentator claims they are so abstract that they can't be easily interpreted. It refers to the thing in question being too self-referential, but could just be a cursory dismisal of the presented content.
Comic 93: Jeremy Irons similarly states a slightly absurd "life goal". 917: Hofstadter is "meta"-related.
[Excerpt from a scientific paper.] Many meta-analysis studies include the phrase “We searched Medline, Embase, and Cochrane for studies…” This has led to meta-meta-analyses comparing meta-analysis methods. e.g. M Sampson (2003), PL Royle (2005), E Lee (2011), AR Lemeshow (2005). We performed a meta-meta-meta-analysis of these meta-meta-analyses. Methods: We searched Medline, Embase, and Cochrane for the phrase “We searched Medline, Embase, and Cochrane for the phrase ‘We searched Medline, Embase, and [cut off]
[Caption below the panel:] Life goal #28: get a paper rejected with the comment “Too meta”


Question

Explanation:
The comic is a reference to a short story by Isaac Asimov " The Last Question ", where humans kept asking successively more complex computers whether entropy can be reversed, thereby preventing the heat death of the universe . The computers always answered "THERE IS AS YET INSUFFICIENT DATA FOR A MEANINGFUL ANSWER". In the end, the final computer figured out the answer, but there were no humans left to give the answer to.
The comic depicts a note to “Isaac” (Isaac Asimov). The note asks Isaac to identify whether he likes the note-writer by choosing either “yes” or “no”. Isaac is supposed to check an answer and hand the note back, but Isaac (whose pen is red) has written and selected a third answer, "there is as yet insufficient data for a meaningful answer", mirroring the way his computers in the short story responded. Notes of this form are stereotypically written by young schoolchildren to gauge or incite romantic interest. This allows impatient children to get an answer during a class, and timid children to get an answer without having to ask the person face to face.
Title text is a reference to the ending in “The Last Question”. The unique capitalization of "IsaAC" in this text implies that IsaAC is an acronym for a type of supercomputer named with a similar convention to the computers in "The Last Question". Instead of the computer climactically coming up with the solution on how to save the universe from entropy when all humanity is gone, like in the “The Last Question", IsaAC comes up with the anticlimactic excuse of an answer 'I like you, but I don't LIKE like you'. “LIKE like” is a childish euphemism for romantic interest. In "The Last Question", a character considers a thought that perhaps AC stands for "analog computer", but in reality this was never the case; for example, ENIAC stands for "Electronic Numerical Integrator And Computer " and UNIVAC stands for "UNIVersal Automatic Computer ". This title text may also be meant to imply that Isaac Asimov was a supercomputer.
The original story can be read here .
Comic 1737: Datacenter Scale also references the short-story in the title text.
[A post-it note which reads:] Dear Isaac Do you like me? □ Yes □ No [Below handwritten in red ink with a checked box:] ☒ there is as yet insufficient data for a meaningful answer