explain xkcd - User contributions [en]

2596: Galaxies

2022-05-04T00:39:48Z

Xyl: Undo revision 234714 by X. K. C. D. (talk)

{{comic
| number = 2596
| date = March 21, 2022
| title = Galaxies
| image = galaxies.png
| titletext = I know it seems overwhelming, but don't worry; I'm sure most of them have only a few stars, and probably no planets.
}}

==Explanation==
{{Quote|Space is big. Really big. You just won't believe how vastly, hugely, mind-bogglingly big it is.|{{w|Douglas Adams}}|{{w|The Hitchhiker's Guide to the Galaxy}}}}

This is another comic with a [[:Category:Facts|Fact]], the second in a row of these fact comics to use an Astronomy fact.

Our best approximation of the number of {{w|galaxies}} in the {{w|observable universe}} is about 200 billion (2 × 1011). That's a lot of galaxies,{{citation needed}} and here [[Randall]] exemplifies this by showing a small circle and estimating that when the comic's picture is viewed at a typical arm's length, expanded to full screen on your typical smartphone, the circle contains roughly 50,000 galaxies (that means of course not the small circle itself, but the volume defined by the viewer's eye, that circle, and an onward conical extension into deep space — and simultaneously back in time — to the respective limits of the observable universe). Most of those far-away galaxies are undetectable by even our most powerful astronomical instruments today, and comparatively few could be seen (let alone positively identified as such) by the naked eye. For example, in the {{w|Hubble Deep Field}}, an image of a small region in the constellation Ursa Major, about 3,000 visible galaxies can be identified.

Measuring in the mid-point of the lines, the circle is about one fortieth of the width of the frame of the comic. The absolute circle size depends on the display resolution, size and mode, but it can reasonably be taken to be 1mm diameter, or 0.5mm radius, giving a total area π r2 or about π/4 square millimeters. You're probably holding the phone about a half a meter away from your eye. The surface area of a sphere is 4 π r2. With a radius of one-half meter, that comes out to be π square meters. Thus, the area of the circle is about 1/4000000 of the area of the sphere, 200 billion galaxies divided by 4 million is the 50,000 average mentioned in the cartoon. A similar mathematics was used for the comic [[1276: Angular Size]], in which the projective sphere was at the Earth's own radius and cross-sectional areas of objects were compared, rather than an approximate count of objects within a given angular spread.

While galaxies usually are between 3,000 to 300,000 {{w|light-years}} across and contain between 10^8 (100 million) and 10^14 (100 trillion) stars, most are so far away from the Earth (upwards of billions of light-years) that they are invisible to the naked eye, or even through most telescopes. When magnified across such vast distances, even something as small as a pinhole expands to huge sizes, easily able to fit tens of thousands of galaxies.

The premise of this comic is that although galaxies are giant, space is unimaginably big and contains a vast number of things. Randall is apparently overwhelmed by this, as shown in the caption: ''Astronomy Fact: There are too many galaxies''.

The title text is Randall reassuring his readers why not to worry of this overwhelming fact. He states that most galaxies only have few stars and probably no planets. However, as mentioned above each galaxy contains a huge amount of stars, and as evident from all his own comics about [[:Category:Exoplanets|exoplanets]], it is now clear that many of the stars in a galaxy also have planets orbiting them. Thus the number of stars and planets in that small circle is much more mind-bogglingly large, than the number of galaxies, and thus the reassurance is sarcasm.

In [[975: Occulting Telescope]] [[Cueball]] expresses a similar sentiment about the number of stars.

==Transcript==
:[An almost white panel with a caption at the top. Then a small circle, much smaller than for instance the letter O in the text is in the center of the panel. A bending arrow points to the circle and beneath the arrow is a caption.]
:Open this picture fullscreen on your phone and hold it at arm's length.
:There are 50,000 galaxies in this circle.

:[Caption below the panel:]
:Astronomy Fact: There are too many galaxies.

{{comic discussion}}

[[Category:Facts]]
[[Category:Astronomy]]

2597: Salary Negotiation

2022-05-04T00:38:43Z

Xyl: Undo revision 233055 by X. K. C. D. (talk)

{{comic
| number = 2597
| date = March 23, 2022
| title = Salary Negotiation
| image = salary_negotiation.png
| titletext = "We can do 0.33 or 0.34, but our payroll software doesn't allow us to--" "NO DEAL."
}}

==Explanation==
[[Ponytail]]'s company would like to hire [[Cueball]] for a job, and she is telling him that their offer for his starting salary is $55,000.

When offered a new job, it is common to negotiate on aspects of the offer such as salary, and employers may offer below the market rate initially in the expectation that the final negotiated amount will be higher. Given that the bedrock of one's future income depends on the outcome of a one-time process requiring skills unrelated to the job one is hired for, it is advisable to take one's time and do as much research as possible.

Cueball has clearly done some research, but perhaps too much as he is flummoxed by this high-stakes situation and starts to ramble with decreasing coherence. First he gets completely confused about the numbers. He says he won't have a penny over $50,000, thus cutting $5000 of the initial offer, and saying he will not have more than that. He realizes this was completely wrong, and corrects to "under", but is still 5000 lower. He then fumbles his words, asking for $60, then $600, then adding "thousand" for $600,000.

Realizing that he is completely off, he asks for a "15% cut of the salary". Here, Cueball seems to confuse salary and commission. "X% cut of the salary" seems like what a recruiter/headhunter may get from their employer as a commission if they successfully make their person hired.

The next word he says is "Raise". This could make sense if he already had a job, and wished to negotiate for a pay raise. After this, he begins to think of raise as in a card game and starts rambling off mainly poker related terms, like "raise", "fold" and "pass". He throws in "double down" in between. This can also be a card game term, as in {{w|blackjack}} where double down means to double a bet after seeing one's initial cards, with the requirement that one additional card be drawn. Lastly, he randomly mentions "fill it up with regular", which could be a request to a gas station attendant to fill a vehicle with "regular" (compared to higher octane) gasoline.

Ponytail tries to ask him something, but Cueball interrupts her, saying he is sorry and that he would like to start over. At this time he takes out several sheets of paper and looks at some charts. He asks if he can borrow a calculator and then asks what's 20% of $55,000. (This would be $11,000.) He eventually settles on a number, $61,333.3 He even states that the decimals of 3 should be repeating, as in forever. This is {{w|0.999...#Algebraic_arguments|exactly}} $61,333⅓. He clearly states he will not take the job for less than that. A [https://hbr.org/2016/03/dont-use-round-numbers-in-a-negotiation 2016 Harvard Business School study] found that avoiding round numbers is a remarkably effective negotiation tactic.

Since this is not that much more than the starting offer Ponytail is ready to accept this and says "Sure, $61,333 is fine." But Cueball interrupts her because what she just offered him was 33⅓ cents less than he asked for.

In the title text it shows that this is not good enough. Cueball has now confused himself to the point he will only accept ''exactly'' what he asked for, the bizarre amount $61,333⅓. Ponytail tries to explain to him that the point 3 repeating cannot be paid in whole cents, and tries to let him know that their payroll software only can handle whole cents, and he thus can get either 0.33 or 0.34 (the latter actually being more than he asks for). Alas, Cueball, either out of panic or a love of mathematics, shouts "No deal!" and lets the job slip out of his hands, because he has completely misunderstood the concept of negotiation.

For more interview-related xkcd comics, see for instance [[:Category:Job interviews]].

This could also be taken in series with Cueball (possibly as a stand in for Randall) misunderstanding classically "adult" ideas, see for instance [[616: Lease]], [[905: Homeownership]], [[1674: Adult]] and [[1894: Real Estate]].

==Transcript==
:[Ponytail sits in an office chair at her desk, with Cueball sitting in a similar chair on the other side with his hands on his knees. Ponytails has her hands on the desk and in front of her, there is a slim thing standing up. It could be a very small screen, but there seems to be no keyboard in front of her. Maybe it is a small tablet with a support for letting is stand up. Behind that there are what appears to be two piles of papers of different sizes.]
:Ponytail: We'd like to extend an offer! The starting salary is $55,000.
:Cueball: Wow. I guess I'm inside a negotiation!
:Ponytail: I... Weird to phrase it like that, but-
:Cueball: ''I can do this.''

:[Zoom in on Cueball's upper half.]
:Cueball: I won't accept a penny over $50,000. Sorry, I mean under. Under $60. I mean, $600. Thousand. $600,000. I want a 15% cut of the salary. Raise. Double down. Fold. Pass. Fill it up with regular.

:[The same shot, except Cueball is now holding three pieces of paper, and he is looking down on them. Ponytail is talking to him from off-panel.]
:Ponytail (off-panel): Are you-
:Cueball: Sorry, sorry. Let me start over.
:Cueball: OK, my chart says...
:Cueball: ...Can I borrow a calculator? What's 20% of $55,000?

:[Back to the scene from the first panel. Ponytail has taken one hand down to her knee, with the other still on the desk. Cueball has put the papers on his lap and has raised his hand in the air holding one finger up. In his other hand he holds either a borrowed calculator or his own smartphone.]
:Ponytail: Listen, if you need to-
:Cueball: I won't take this job for less than $61,333 point 3 repeating!
:Ponytail: Sure, $61,333 is fine. That's actually-
:Cueball: '''''Point 3 repeating or I walk!'''''

{{comic discussion}}

[[Category:Job interviews]]
[[Category:Comics featuring Ponytail]]
[[Category:Comics featuring Cueball]]

2599: Spacecraft Debris Odds Ratio

2022-05-04T00:36:28Z

Xyl: Undo revision 235681 by X. K. C. D. (talk)

{{comic
| number = 2599
| date = March 28, 2022
| title = Spacecraft Debris Odds Ratio
| image = spacecraft_debris_odds_ratio.png
| titletext = You say this daily walk will reduce my risk of death from cardiovascular disease by 30%, but also increase my risk of death by bear attack by 300%? That's a 280% increased! I'm not a sucker; I'm staying inside.
}}

==Explanation==
{{incomplete|Created by an EVENS RATIO - Do NOT delete this tag too soon.}}
This comic is a misunderstanding of statistics very similar to that of [[1252: Increased Risk]]. It explains that going outside for more than 5 hours per day significantly increases your risk of head injury from falling spacecraft, and advises to limit outside activity to avoid this risk.

However, since the odds of being hit in the head by (any part of) a falling spacecraft are [https://www.livescience.com/33511-falling-nasa-satellite-uars-risk.html astronomically low to begin with], quadrupling it or more still results in a negligible probability. The horizontal error bars for times greater than 4 hours are marked with asterisks to indicate they are significantly different from the reference value at 0 hours, as indeed those error bars don't overlap the vertical line for the 0-hours reference value.

{{w|Error bar}}s are graphical representations of the variability of data and used on graphs to indicate the error or uncertainty in a reported measurement.

Presenting the data by hour brackets hides the data distribution inside each bracket. If the data were presented hour by hour, and not by groups of hours, they may show a different threshold of increased risk or no threshold (odds ratio could be linear).

The graph and error bars are based on a {{w|Monte Carlo Method|Monte Carlo simulation}}, a type of computational algorithm that uses repeated random sampling to obtain the likelihood of a range of results of occurring; see, for instance, this article about [https://www.ibm.com/cloud/learn/monte-carlo-simulation Monte Carlo simulations]. Additionally, this may indicate that the entire study was conducted via a Monte Carlo simulation and that no real data was collected adding to the absurdity of the claim that more time spent outside could lead to an increased risk of head injuries due to falling space craft. Indeed, it is so rare for humans to be struck by spacecraft debris that a simulation is probably the only way to study the risk; an absurdly large sample size, involving tens of millions of participants over several decades, would be necessary to obtain significant experimental data.

The specific reference to falling spacecraft is likely inspired by events happening around the time of this comics release (March 2022). Around a month before this was posted, the head of the Russian space agency, {{w|Roscosmos}}, warned that sanctions against Russia (mostly those over the {{w|2022 Russian invasion of Ukraine}}) could result in the {{w|International Space Station}} crashing. Since the Russian section of the space station is the one that provides propulsion (although it is built to rely on the power generated by the other sections), this was taken seriously and as of when this was posted, {{w|NASA}} was trying to come up with alternative stabilization strategies in case the situation worsened. There was also a recent [https://www-uol-com-br.translate.goog/tilt/noticias/redacao/2022/03/17/parte-do-foguete-spacex-e-encontrada-por-morador-do-pr.htm?_x_tr_sl=auto&_x_tr_tl=en&_x_tr_hl=pt-BR&_x_tr_pto=wapp report] of some 600 kg space rocket debris found in Brazil.

The title text makes a similar joke. While the increase in chances of death by a bear attack are greater when going outside than the decrease in chances of death by cardiovascular disease, by getting out to exercise, it is incorrect to combine them in this way, since cardiovascular disease has a much higher starting chance of death, and reducing it by 30% has a much more significant effect on overall life expectancy than quadrupling the very very small chance of death by bear attack. At least for the majority of us who don't live in or near wild bears' natural habitats.

The "280% increase" of the title text is also an error, though perhaps not for reasons that are obvious at first (for instance, the correct calculation is not "300% − 30% = 270%"). To "increase by 300%" means multiplying the probability by (1 + 3.0) = 4.0, while to "decrease by 30%" means multiplying by (1 − 0.3) = 0.7. Combining these means multiplying by both, for an overall change of 4.0 × 0.7 = 2.8, or 280%. However, this result means the risk has increased ''to'' 280% of its old value, not ''by'' 280%. And in any case, it is ''still'' not valid to simply combine two changes in wildly different risks like this.

===Odds & Odds Ratios===

The odds of an event is the probability that it happens divided by the probability that it doesn't happen. People often express odds as a ratio (e.g. the odds of rolling a 6 on a 6-sided dice might be expressed as 0.16777... : 0.83333..., or equivalently as 1:5), but it is important to note that such ratios are not ''odds ratios'' (it would be fitting to call this a "probability ratio", but this terminology is not standard).

An odds ratio is the odds of event O happening, given that some other event E has occurred, divided by the odds of O given that E has not occurred. O is sometimes called an "outcome" and E is sometimes called an "exposure", because people are often interested in comparing things like the odds of getting lung cancer (O) given that you smoke (E) to the odds of getting lung cancer given that you don't smoke, as a way of measuring the extent to which exposure to E influences outcome O. In the case of the comic, the outcome variable O is the event of getting a head injury from falling spacecraft debris, and the exposure variable E is the event of spending H hours per day outside, for various values of H. The comic appears to be saying that for each value of H, there are two options for E: either you spend H hours per day outside or you never go outside.

So for small values of H (e.g. 1 hour per day), the comic is saying that the event of being hit by spacecraft debris is more or less independent of the event of spending H hours per day outside, which is to say that the odds of being hit is more or less the same regardless of the choice you make between spending H hours per day outside and never going outside. Hence the dot on the 1-hour bar is close to 1, because the two odds are more or less equal (the dot appears to represent an average estimate of the odds ratio).

Note that when calculating the odds ratios for this comic, the odds in the denominators are always the same, as they are the odds of being hit given that you never go outside, which does not depend on H. So when the comic says that the odds ratio is above 3 for H={11+ hours per day}, it is effectively saying that the odds of being hit when you spend this much time outside is a bit more than 3 times the odds of being hit when you spend 1 hour per day outside.

Suppose the probability of being hit is: P when you spend 1 hour per day outside, and Q when you spend 11+ hours per day outside. The odds of being hit under these two exposures are P/(1-P) and Q/(1-Q) respectively, and because the odds ratios have equal denominators, the comic is saying that Q/(1-Q) = kP/(1-P), where k is a bit more than 3. If we rearrange this to get an expression for Q, we get:

<pre>
Q/(1-Q) = kP/(1-P)
<=> Q(1-P) = kP(1-Q)
<=> Q-QP = kP-kPQ
<=> Q+kPQ-QP = kP
<=> Q(1+kP-P) = kP
<=> Q = kP/(1+kP-P)
<=> Q = P/(P+(1-P)/k) {by dividing the numerator and denominator by k}
</pre>

As P is negligibly small, 1-P is very close to 1, and P+(1-P)/k is very close to 1/k. Thus Q is very close to kP (i.e. a bit more than 3 times P), meaning that the probability of being hit when you spend 11+ hours per day outside is still negligibly small. Thus, the comic's suggestion that we spend 4 hours or less outside based on the estimated odds ratios is extremely misguided.

==Transcript==
:[A chart is shown. Above the chart there is a heading, with a subheading below it:]
:Odds ratio for head injuries from falling spacecraft debris
:(Monte Carlo Simulation)

:[The chart is rectangular with the X-axis labels above the chart with numbers from 1 to 5. These are places over vertical lines. The first at 1 is black, the other four are light gray. There are three smaller light gray ticks between each set of lines, and one on either side of the first and last. The distance between lines gets smaller and smaller towards the right, probably logarithmic.]
:X-axis: 1 2 3 4 5

:[The Y-axis is not scaled; there are no ticks or lines. Instead it just gives five labels from top to bottom. Above those labels there is an arrow pointing to the top one with a label above explaning the axis.]
:Hours spent outdoors per day
:Y-axis:
::0 (ref)
::1
::2-4
::5-10
::11+

:[Aligned with each of these five divisions of the Y-axis there is a dot. The top one is placed on the solid line under 1 as a reference point. The other four dots all have long error bars, with the dots at the center of these. The second dot is a bit to the left of the solid line, with the error bar going almost to the left edge of the graph and halfway to the first light gray line to the right. The third dot is located halfway between the solid and the first light gray line with the error bar just crossing the solid line, and almost reaching the gray line. The fourth dot is about a third way between the first and second of the gray lines, with the error bar crossing both these lines. The fifth and last dot is just past the second gray line, with the error bar crossing both that, going more than half toward the first gray line, and also just past the third gray line. On the same height as the two bottom dots, there are asterisks just right of the edge of the graph.]
:<nowiki>*</nowiki>
:<nowiki>*</nowiki>

:[Below the panel there is a caption:]
:Our new study suggests that spending more than 5 hours outside significantly increases your risk of head injury from spacecraft debris, so try to limit outdoor activities to 4 hours or less.

==Trivia==
*In the [https://www.explainxkcd.com/wiki/images/archive/d/d5/20220329223238%21spacecraft_debris_odds_ratio.png original version] of the comic the Y-axis label referred to "hours spent outdoors". So more than four hours spent outdoors in one's lifetime would be a problem.
**But later the comic was edited to specify "hours spent outdoors per day", which makes more sense.
*When the new version was uploaded, Randall again made the error of making the two versions of the comic image the same size, as he did earlier in [[2576: Control Group]], see that comic's [[2576: Control Group#Trivia|trivia]]
**This resulted in the problem that the comic broke the boundaries on the xkcd website.
*This comic's title text has a typo in the sentence "That's a 280% increased".

{{comic discussion}}

[[Category:Charts]]
[[Category:Statistics]]
[[Category:Space]]
[[Category:Animals]]

2600: Rejected Question Categories

2022-05-04T00:33:40Z

Xyl: Undo revision 234029 by X. K. C. D. (talk)

{{comic
| number = 2600
| date = March 30, 2022
| title = Rejected Question Categories
| image = rejected_question_categories.png
| titletext = You can click to preorder to get a copy of What If? 2 when it comes out 9/13, assuming we all make it past the spider situation(?) on Tuesday(?).
}}

==Explanation==
{{incomplete|Created by a HANGING ROCK OF MASS DESTRUCTION LAUNCHED AT A VOLCANO BY HOT SINGLES IN YOUR AREA- Please change this comment when editing this page. Do NOT delete this tag too soon.}}
[[Randall]] recently announced, in [[2575: What If? 2]], that he is publishing a new ''[[what if?]]'' book based on reader-submitted questions. This comic is another [[:Category:Book promotion|promotion]] of the book, and the entire comic is a link to his [https://xkcd.com/what-if-2/ what if? 2] page on xkcd.

This comic shows the [[#Question categories|categories of questions]] he claims to have received, but rejected to use in his book, giving an example question for each category. In typical xkcd fashion, these begin out by being plausible, although often unlikely to have been submitted as a ''what if?'' question, moving in to more and more absurd types of questions, especially with the last question, that appears to be a combination of all previous categories and is therefore marked "?????"

The title text refers to the launch date of the book September 13, rendered in the American style 9/13. This format can be confusing to non-Americans, although usually not when the date is larger than 12, since it would then appear to reference the 9th day of the 13th month. This "13th month" was, however, referenced in the first comic about the book: [[2575: What If? 2]]. See also Randall's take on the date format, {{w|ISO 8601}}, in [[1179: ISO 8601]].

Randall then continues the title text by referencing the second to last category with vague ominous questions. The example question here asks if there is need to worry about spiders after Tuesday. So Randall notes that the release date, 5.5 months after the release of this comic, is of course assuming anyone will survive past next Tuesday (2022-04-05).

Tuesday has been notably referenced in [[277: Long Light]], [[564: Crossbows]], [[1099: Tuesdays]] and most notably in [[1245: 10-Day Forecast]], where it seems that the last day ever will be a Tuesday. Tuesday is the second day of the week, and notably, the Tuesday of the week following the publication of this cartoon (April 5th, 2022) was the Day of the Spiders.

==Question categories==
{| class="wikitable"
|'''Category'''
|'''Question'''
|'''Explanation'''
|-
| People cheating on homework
| What if I made a pendulum by hanging a rock on a 2.75 meter string? What would its period be in seconds? (Show your work!)
| This appears to be a physics student trying to get out of doing their work by presenting the question for Randall to answer in ''What If'' (which is a common occurrence on question-and-answer sites such as Stack Overflow). Most school homework requires the student to "show their work", i.e. write out their process of solving the question. Making students show their work serves two purposes: it allows students to score partial credit on an incorrect answer if they show the right methodology and basic understanding even if they make a wrong turn along the way; it also prevents students from simply cheating by looking up the right answer without showing how they got that answer — the student including this caveat in their email is a giveaway as to their tactic (along with the boring nature of their inquiry).
|-
| Medical advice
| What if you got a scratch and the next day your hand looked like this [''📎 attachment'']? Should you see a doctor or what?
| Randall is not a physician, is not qualified to give medical advice, and will not answer medical questions. This was a problem on early Wikipedia which, for a time, required all articles covering medical topics to point to a {{w|WP:MEDICAL|Medical Disclaimer}}. This was also an issue covered in the 1st ''what if?'' book, under Weird and Worrying Questions from the Inbox, where a reader asks about the effects of a toxin on the excretory system. If your body is not behaving in the way you expect, consulting with a medical professional is, in general, a good idea.
|-
| Personal
| Why don't the squirrels in my yard like me???
| Randall has no way of knowing why the wildlife in a given area dislike a specific person, especially if this hints at a specific animosity/belligerence and not just general avoidance of humans as a perceived threat. These kind of questions are common on sites like reddit, and are usually covered by general explanation of animal behaviors unless the asker supplies more information in the comments. However, the choice of squirrels are likely not random since [[:Category:Squirrels|Squirrels]] are a recurring theme on xkcd and has often been [https://www.explainxkcd.com/wiki/index.php/Category:Squirrels#Uses_in_other_xkcd_media: used in what if?] (sometimes as {{what if|105|placeholder}} for a potentially horrible image).
|-
| Spam
| Do you want to meet lonely singles in your area tonight?
| This is a common online popup advertisement and is generally considered undesirable. An unavoidable side effect of Randall having an email address published where the public can find it is that spammers have just as much access to it. Most people do not respond to spam emails, and Randall is no exception.
|-
| Phishing
| Have you recently been the victim of phishing? To check, log in to your account by clicking here.
| Again, because Randall's What-If email is publicly available, phishers have access to it and can probe the recipient for information. Randall is experienced enough to recognize a phishing attempt and ignore it. This type of phishing scam, in which the scammer requests your personal data for the purported purpose of checking if it has been "stolen" thereby "stealing" it himself, has become more common as people have become aware of phishing, and phishers have thus embraced the possibility of exploiting a new niche in the layers of naivete.
|-
| Requests for help with a crime
| Using modern science, what would be the fastest way to get through this bank vault door? [''📎'' blueprints]
| No, Randall is ''not'' going to help a criminal commit breaking and entering or robbery, thank you very much. A common problem with heist movies is that they show a believable{{Citation needed}} method for breaking in to a vault which people then try to replicate in real life. Such movies often portray an expert in some other field being "smart enough" to craft the plan, sometimes unwittingly.
|-
| Unanswerable
| Why am I me and not someone else
| There is a lot in this question that could be unpacked, and Randall doesn't want to touch on any of it.

At face value the question is asking about {{w|Philosophy of mind}}, a branch of philosophy with many questions that are unanswerable due to our own imperfect understanding of mind. The asker is inquiring as to what process is responsible for designating that their consciousness be tied to the body in which they currently reside, as opposed to another body presumed to have consciousness; furthermore, they likely wish to know the mechanics behind how this process works. There is as yet insufficient data for a meaningful answer.

It's also quite possible the asker is feeling melancholic and unsatisfied with their life. Randall doesn't feel qualified to try diagnosing or treating someone's existential depression.
|-
| Vague
| What is going to happen? (Be specific)
| Some humor is derived from the request for specificity in the question, which completely lacks any sort of specificity of its own.
|-
| Vague and ominous
| Will I have to start worrying about spiders after Tuesday?
| This implies some event that occurs on a (possibly next?) Tuesday. This event may relate to spiders in some way, and cause those who do not currently worry about spiders to do so. If you do not currently worry about spiders, this question does not give enough specifics for Randall to intelligently answer whether or not you should start.
Possibly a [[:Category:Red Spiders|red spiders]] reference. Could also be a reference to [[1688: Map Age Guide]] where some dangerous event involving spiders is set to happen in 2022.
|-
| ?????
| Hi, we're lonely singles in your area, and we're wondering what would happen if we shot a nuclear bomb into a volcano! Click here to log in and tell us ...
| If nothing else, this entry is clearly made up by Randall, as it appears to be a combination of as many prior categories as he has room for, specifically Spam, Phishing, and an already-answered question, before getting cut off by the bottom of the panel.

"Would it be possible to stop a volcano eruption by placing a bomb (thermobaric or nuclear) underneath the surface?" was a question featured in the first ''what if'' book. Randall answered with an emphatic "No!"
|}

==Transcript==
{{incomplete transcript|Do NOT delete this tag too soon.}}
In ''What If? 2'' (xkcd.com/whatif2), I answer ridiculous questions sent in by readers about everything from volcanoes to spaceships to soup.

Here are a few of the common types of question that I did ''not'' answer:

[In separate boxes for each category]

[In row 1:]

People cheating on homework: What if I made a pendulum by hanging a rock on a 2.75 meter string? What would its period be in seconds? (Show your work!)

Medical advice: What if you got a scratch and the next day your hand looks like this [''📎 attachment'']? Should you see a doctor or what?

Personal: Why don't the squirrels in my yard like me???

[In row 2:]

Spam: Do you want to meet lonely singles in your area tonight?

Phishing: Have you recently been the victim of phishing? To check, log in to your account by clicking here.

Requests for help with a crime: Using modern science, what would be the fastest way to get through this bank vault door? [''📎'' blueprints]

[In row 3:]

Unanswerable: Why am I me and not someone else

Vague: What is going to happen? (Be specific)

Vague+Ominous: Will I have to start worrying about spiders after Tuesday?

?????: Hi, we're lonely singles in your area, and we're wondering what would happen if we shot a nuclear bomb into a volcano! [partially cut off horizontally:] Click here to log in and tell us

{{comic discussion}}

[[Category:Book promotion]]
[[Category:Physics]]
[[Category:Squirrels]]
[[Category:Spiders]]
[[Category:Nuclear weapons]]

2602: Linguistics Degree

2022-05-04T00:32:40Z

Xyl: Undo revision 234900 by X. K. C. D. (talk)

{{comic
| number = 2602
| date = April 4, 2022
| title = Linguistics Degree
| image = linguistics_degree.png
| titletext = You'd think 'linguistics' would go to someone important in the field, but it's actually assigned to a random student in Ohio who barely graduated and then went into automotive marketing.
}}

==Explanation==
{{incomplete|Created by a JACKALOPE SLURPING UP A BASSOON, GRADUATED BACHELOR OF SCIENCE WITH A GUARDIANSHIP OF 'EXPLAIN' - Please change this comment when editing this page. Do NOT delete this tag too soon.}}
[[Hairbun]] hands [[Megan]] a linguistics degree, and informs her she is now "in charge of" the word '{{wiktionary|bassoon}}.' Watching this, [[Ponytail]] and [[Cueball]] compare the words they were assigned when ''they'' got their linguistics degrees, '{{wiktionary|jackalope}}' and '{{wiktionary|slurp}}' respectively. Ponytail thinks bassoon is a cool word but thinks her own is better, whereas Cueball is not satisfied with his word. A bassoon is a woodwind musical instrument with a double reed, while a jackalope is a mythical creature, a ''jackrabbit'' crossed with an ''antelope''.

It is never clarified what being "in charge of" a word entails. It could mean being in charge of keeping track of the word, or having actual authority over the use of the word, which is unlikely as normally [[1726|language use cannot be dictated by a single person]]. Also, no specific university has control over all of linguistics as far as we know, so it would require every university capable of giving people linguistics degrees to co-operate, so nobody is assigned the same word. Any well-educated member of the linguistic community will know what is being suggested is impossible hence why they are the only ones aware of how important it is.

The title text merely furthers how seemingly random the entire situation is. The word "linguistics" was assigned to a "random student in Ohio who barely graduated and then went into automotive marketing", who we can assume isn't very important to the field of linguistics.{{Citation needed}} But this means that no one is actually taking care of this important word, since it must be assumed that the student is no longer interested in linguistics.

The idea of individuals having a guardianship of an idea or concept has appeared in science fiction. For example, in ''{{w|Fahrenheit 451}}'' characters have memorised books to save them from book-burning and... spoiler-stuff.

==Transcript==
:[Megan, who is wearing a graduation cap, receives a degree which is handed to her by Hairbun. They are standing on a podium with Ponytail and Cueball standing below as onlookers.]
:Hairbun: Congratulations on the degree! Your word is "Bassoon."
:Ponytail: Oh nice! Not as cool as my "Jackalope," but still not bad.
:Cueball: You all are lucky. I'm stuck with "Slurp."

:[Caption below panel:]
:Every linguistics degree comes with one word that you're put in charge of.

{{comic discussion}}

[[Category:Language]]
[[Category:Comics featuring Hairbun]]
[[Category:Comics featuring Megan]]
[[Category:Comics featuring Ponytail]]
[[Category:Comics featuring Cueball]]
[[Category:Characters with hats]]

2603: Childhood Toys

2022-05-04T00:32:11Z

Xyl: Undo revision 235786 by X. K. C. D. (talk)

{{comic
| number = 2603
| date = April 6, 2022
| title = Childhood Toys
| image = childhood_toys.png
| titletext = The rope keeps breaking, I'm covered in bruises and scrapes, and I've barely reached the end of my driveway, but I don't care--I'm determined to become the first person to commute to work by tetherball.
}}

==Explanation==
{{incomplete|Created by YOUR BOSS LEAVING WORK BY A SPINLAUNCHER ON A SLIP'N'SLIDE NEXT TO YOUR PARKED HANDMADE ROBODRAGON - Please change this comment when editing this page. Do NOT delete this tag too soon.}}
This comic shows various objects, ranked by how practical they would be for long-distance transportation. The objects are described as childhood toys.

The "Practical" panel shows objects designed for convenient transportation, namely {{w|bicycles}} and {{w|Motorized_scooter|electric scooters}}. Most people know how to ride a bicycle, and can easily go several miles on it. Scooters (shown in the comic panel) are also relatively easy to use, and may have a motor allowing them to be used for significant distances — the one shown has the appearance of one with a battery unit rather than being 'leg-propelled', and is named as such in the list for which it has been depicted. These are not considered "toys" at adult size as they are widely used for transport, but children's bikes and scooters (particularly unpowered scooters) not used for transport would generally be considered toys. The practicality of bicycles and e-scooters tends to depend more on local infrastructure and amenities (i.e., the presence of a safe cycle route and the destination being within a sensible distance) than on the equipment itself. Bicycles can carry {{w|Cargo bicycle|substantial loads}}. In some countries e-scooters are legally restricted or prohibited on public roads which may make commuting on them unviable.

The "Less Practical" panel has objects designed for transportation, but which may be harder to use than the first panel. {{w|Skateboards}} and {{w|roller skates}}, while designed for transportation, don't work great over long distances or when carrying objects, and {{w|Big Wheel (tricycle)|Big Wheels}} and {{w|unicycles}} (shown in the panel) are simply less practical bikes.

In the "Impractical" panel are objects that are designed for transportation, but are ''very much not'' designed for convenience, especially over long distances. {{w|Stilts}} are long poles that one stands on to extend their legs; while they increase the user's stride length, it takes quite a bit of practice to use them, especially if they're very long. A {{w|jump rope}} is a rope that the user swings around their body while they jump over it whenever the rope passes below their feet; it doesn't actually provide any transportation by itself, the user is simply hopping to their destination, which is a very tiring way to travel (but very good exercise if you can do it). A {{w|toy wagon|wagon}} has no propulsion of its own, it has to be pulled by the user; parents sometimes use it to transport their children short distances (such as to a playground). Larger wagons are used commercially. A {{w|Pogo stick}} is a pole with a spring at the bottom and a platform for standing on, which can be used to bounce; while fun for bouncing a few yards (as shown in the panel), like the jump rope it would be tiring for long distances.

The "Very Impractical" panel has objects that may be used for transportation, but to an ''incredibly'' limited degree. {{w|Slip_%27N_Slide|Slip 'N Slides}} (shown in the panel) only work (effectively) downhill, and only where they are placed down. {{w|Trampolines}} and {{w|Tire swing|Tire swings}} could let you go somewhere, but you'd need to set up multiple in a row leading to your destination beforehand. {{w|Hot Wheels}} cars could be put onto the bottom of shoes to create ''extremely'' ill-advised{{citation needed}} improvised rollerskates, but the car on its own has effectively no merit for transportation.

The title text refers to {{w|tetherball}}, a game found in many playgrounds where a ball is attached to a pole by a long rope. This is also very impractical, as the rope just winds around a stationary pole. It's possible that he is swinging from the rope and letting go (which would explain the bruises and scrapes, as well as the torn rope), but there is no ''remotely'' practical way to use this to commute.{{citation needed}} Nevertheless, if you were able to swing quickly enough and cut the rope at exactly the right moment, you might be able to achieve a short commute to a nearby target. This method may have been inspired by NASA [https://www.aerospacetestinginternational.com/news/space/spinlaunch-to-test-suborbital-accelerator-launcher-with-nasa.html purchasing a launch] via the [https://www.spinlaunch.com/ SpinLaunch] rocket system the same week as the comic appeared.

==Transcript==
{{incomplete transcript|Do NOT delete this tag too soon.}}
:[Title:] Childhood Toys
:[Subtitle:] By Practicality for Commuting

:[Caption of the first box:] Practical
*Bicycle
*Electric Scooter
:[Cueball, wearing a helmet, drives by on an electric scooter, passing another Cueball and Hairbun, who is holding a briefcase.]
:Scooter Cueball: Hi, boss!

:[Caption of the second box:] Less Practical
*Skateboard
*Roller Skates
*Big Wheel
*Unicycle
:[Ponytail rides by White Hat on a unicycle.]
:Ponytail: Good Morning!

:[Caption of the third box:] Impractical
*Stilts
*Jump Rope
*Wagon
*Pogo Stick
:[Cueball bounces past Megan on a pogo stick.]
:Pogo Stick: Boing boing
:Cueball: How's it going?

:[Caption of the fourth box:] Very Impractical
*Trampoline
*Tire Swing
*Hot Wheels
*Slip 'N Slide
:[Cueball slides past Hairy(?) on a Slip 'N Slide.]
:Cueball: Wheeeee
:Cueball: Hi Boss!

{{comic discussion}}
[[Category:Comics featuring Cueball]]
[[Category:Comics featuring Hairbun]]
[[Category:Comics featuring Ponytail]]
[[Category:Comics featuring Megan]]
[[Category:Comics featuring Hairy]]
[[Category:Comics featuring White Hat]]
[[Category:Multiple Cueballs]]

2604: Frankenstein Captcha

2022-05-04T00:31:49Z

Xyl: Undo revision 235407 by X. K. C. D. (talk)

{{comic
| number = 2604
| date = April 8, 2022
| title = Frankenstein Captcha
| image = frankenstein_captcha.png
| titletext = The distinction between a ship and a boat is a line drawn in water.
}}

==Explanation==
{{incomplete|Created by a CAPTCHA RATED ARGH-Please change this comment when editing this page. Do NOT delete this tag too soon.}}

This comic strip is a play on the meanings (and misunderstanding) of the name "Frankenstein". ''{{w|Frankenstein; or, the Modern Prometheus}}'' is an 1818 novel by Mary Shelley about a medical student named Victor Frankenstein who creates an artificial life-form. The man he creates once describes himself as "the Adam of [Frankenstein's] labour" in the book, and strictly speaking is properly known as "Frankenstein's ''monster''" (or perhaps "creation" or "son"), but is often erroneously called "Frankenstein" himself. This has been fertile ground for many, many debates about whether the monster could also properly be called "Frankenstein," either as a family name, an honorific, or simply because it's more recognizable and convenient. Randall has weighed in on the debate himself in a previous comic, [[1589: Frankenstein]].

The CAPTCHA shown in the comic instructs the user to select all tiles containing Frankenstein. The tiles include both a reanimated corpse resembling Frankenstein's monster and a scientist yelling, [https://www.youtube.com/watch?v=1qNeGSJaQ9Q "It's alive!”] who is clearly intended to be Victor Frankenstein. The problem arises from the contrast between various definitions of the term Frankenstein. Going just off the book's text, the monster has no name, so the correct answer to the CAPTCHA is just the left square of the third row. However, the character depicted there is clearly ''Henry'' Frankenstein from the famous {{w|Frankenstein (1931 film)|1931 film adaptation}} (Victor Frankenstein never said the words "it's alive!" in the book), and likewise the creature depicted is clearly inspired by {{w|Boris Karloff}}'s iconic portrayal in that film and its sequels. If the images are captured from that film, then all four of them could be said to be "containing (a subset of) ''Frankenstein'' (the 1931 film)".

Some CAPTCHAs - especially Google's widely spread reCAPTCHA - nowadays serve a dual purpose: (1) to separate human users from bots by way of intelligent interaction, and (2) to train a neural network, hence the "correct answer" to image recognition CAPTCHAs is not known ahead of time and is merely based on the most commonly-chosen tiles. Users who frequently face CAPTCHAs are familiar with the dilemma of having to choose tiles that they know do not contain the requested object but which they know were likely chosen by previous users, making the CAPTCHA one part object-identification exercise and one part human-psychology exercise. Thus, a user who knows that "Frankenstein" refers only to the scientist would face this CAPTCHA with dread, uttering "Oh No" as they realize that they must select the tiles containing the monster, and possibly not even be allowed to select the tile containing the actual scientist Victor Frankenstein if they want to pass the CAPTCHA.

Alternatively, this comic strip with its "Oh No" caption could be referencing [[1897]], which would imply that someone had actually created a Frankenstein's monster which needs to be located as soon as possible.

Many of the other tiles appear to be pictures of entities that inspire similar pedantry. For example, there is a picture of a turtle (or possibly a tortoise, or a reference to the {{w|Voight-Kampff_machine|Voight-Kampff test}} used in a manner analogous to CAPTCHA), a ship (or possibly a boat), {{w|Link (The Legend of Zelda)|Link}} (the name given to each of several protagonists that appear across generations and timelines, throughout the ''{{w|Legend of Zelda}}'' video games, who many erroneously refer to as Zelda), a pond (or possibly a lake, a puddle, or a {{w|mirage}}), a squash or pumpkin (often subject to the ''fruit or vegetable'' debate), an erupting volcano (with lava, or is it magma?), and the planet Pluto (or is it a dwarf planet?). Other tiles seem to be inspired by images that commonly occur in actual captchas, like the STOP sign or the traffic light. However, at least some of these may also be meant to fall into the category of entities that inspire pedantry, for example: because traffic lights can also be called traffic signals or stoplights; many people thinking that the shape of a stop sign is a hexagon, not an octagon; and the definition of a sandwich (previously discussed as a “random semi-ironic obsession” in [[1835]]).

The title text refers to one of the methods used to distinguish a ship from a boat. When making a turn, if the vessel leans towards the inside of the turn circle then it is considered a boat, whereas if the vessel leans away from the turn circle it is considered a ship[https://www.youtube.com/watch?v=L1iM2CG5QQ8]. Since the vessel generates a wake as it moves, checking whether it is a boat or a ship can be done while it is literally drawing a line on the water (the wake). The phrase "a line drawn in water" is also an idiom for something ephemeral. Ironically, it has persisted for a long time and dates back at least to the early Buddhists. (e.g. [https://suttacentral.net/an3.132/en/sujato?layout=plain&reference=none&notes=asterisk&highlight=false&script=latin| AN 3.132] & [https://suttacentral.net/an7.74/en/sujato?layout=plain&reference=none&notes=asterisk&highlight=false&script=latin| AN 7.74]). The distinction between a ship and a boat is also unclear, having changed over time, with no universally accepted rule to {{w|Ship#Nomenclature|distinguish between the two}}. The title text is also a pun on the common idiom "drawing a line in the sand." The title text could also be referencing the image of a boat or ship that appears as one of the CAPTCHA tiles in the comic, where Randall has drawn a squiggly line often used in crude drawings to represent a waterline.

==Transcript==
{{incomplete transcript|Do NOT delete this tag too soon.}}

:[A captcha design, with a header and four rows of four pictures each below it. The header, in white lettering on a blue background, reads:]
:To continue, please click
:All squares containing
:Frankenstein

:[The pictures, all with gray backgrounds, are as follows, from left to right in each row:]

Row 1
* Tortoise (or turtle)
* Ship (or boat)
* Frankenstein's monster (often mistaken as Frankenstein) waking up from a slab, while lightning strikes.
::Monster: GRRR
* Link from Legend of Zelda series (often mistaken as Zelda)

Row 2
* Lake (or pond), possibly a mirage, in the Egyptian desert
* Megan (or Science Girl, or Danish--possibly a direct joke about this wiki)
* The top of a volcano spewing lava (or magma)
* Pumpkin (or squash [fruit vs vegetable])

Row 3
* A mad scientist (Victor Frankenstein) throwing a switch while lightning strikes outside
::Frankenstein: It's alive!
* Sandwich
* Stop sign
* Girl running away from Frankenstein's monster
::Girl: Monster!

Row 4
* Rocket (spaceship) flying by Pluto (planet or dwarf planet)
* Cueball and Ponytail standing next to each other
* Traffic light (also called a stoplight, possibly mistaken as stop sign?) (called a [https://en.wikipedia.org/wiki/Traffic_light robot] in South Africa/Zimbabwe)
* Frankenstein's monster

:[Caption below the panel]:
:Oh no.

{{comic discussion}}
[[Category:Comics with color]]
[[Category:CAPTCHA]]
[[Category:Frankenstein]]
[[Category:Animals]]
[[Category:Food]]

2610: Assigning Numbers

2022-05-04T00:07:01Z

Xyl: Undo revision 234637 by X. K. C. D. (talk)

{{comic
| number = 2610
| date = April 22, 2022
| title = Assigning Numbers
| image = assigning_numbers.png
| titletext = Gödel should do an article on which branches of math have the lowest average theorem number.
}}

==Explanation==
{{incomplete|Created by YÖDA'S COMPLETENESS THEOREM - Please change this comment when editing this page. Do NOT delete this tag too soon.}}

'''This explanation is by mathematical necessity either incomplete or incorrect.'''

[[Cueball]] is falling into a common trap, because a little knowledge is a dangerous thing. Faced with some sort of information, of an unknown kind but seemingly not intrinsically mathematical in nature, he has decided that one possible way to proceed is to somehow translate everything into values which can be combined and compared numerically.

This is a very common thing to do, in fields as diverse as {{w|computational linguistics}} or {{w|sports analytics}}, and can be a powerful tool for understanding and learning new things about a subject as {{w|Data science}} tries to extract knowledge and insights from potentially noisy and disordered facts. But it is also used to implement bad science by using incorrect or misguided ideas about how to represent the source material. While it's possible to casually assign numeric values to random pieces of data, these numbers are generally not meaningful enough to compute with and draw any useful inferences from. It is generally possible to perform statistical analysis only on actual measurements, not on what may effectively be arbitrarily-assigned values.

Machine learning algorithms, which are commonly used by data scientists, typically require all their inputs to be numerical. However, most datasets contains categorical features (e.g. the description of a piece of furniture: chair, table, ...). Data scientists therefore use encoding techniques to convert these categorical features to a numerical form so they can be used as inputs to a machine learning model. For instance, label encoding consists of arbitrarily assigning an integer to a category (chair=0, table=1, ...) which may appear meaningless to most observers. In various cases, they may be right.

So, as well as being the mechanism that underlies one of the most profound theorems of 20th century mathematics, it can be mis-used for all kinds of bad or misguided science. From Cueball's attitude, it is far from clear that his attempt will reliably translate his project into a numerical system, nor that his attempt to "do math on it!" will be any more competent.

One of the major characters who looked at the concept is Kurt Gödel. He introduced the idea of {{w|Gödel numbering}} with his landmark {{w|incompleteness theorems}}. In it a unique natural number is assigned to each axiom, statement, and proof, which might otherwise be difficult to accurately process in any other kind of approach. Instead, it is now possible to create metamathematical statements in the language of mathematics.

This allowed Gödel to make the statement "This statement cannot be proven based on the axioms provided" in a mathematically rigorous way. A simple proof by contradiction shows that the statement cannot be false, and therefore (in most logical systems) must be true. The proof goes as follows: 1. Assume that "This statement cannot be proven from the axioms" (Call this statement G) is false (Call this assumption A). 2. Therefore G can be proven from the axioms (Because the negation of the negation is an affirmation. Based only on A) 3. The axioms exist (Call this assumption B). 4. Therefore, G is true (via {{w|Modus ponens}} applied to 2 and 3, based on A and B). 5. Therefore, G and also not G (via And Introduction applied to 1 and 4, based on A and B). 6. This is a contradiction, and therefore A or B must be wrong. We are not willing to sacrifice assumption B, so we must conclude that A is false, given B ({{w|Reductio ad absurdum}} applied to 1,3, and 5). 7. Therefore, G.

Notice that the truth of Gödel's statement does not depend on any particular set of axioms, and adding axioms (such as "Gödel's particular statement is true") only opens up new iterations of the statement which cannot be proven based on the expanded set of axioms (A statement such as "All statements of a similar nature to Gödel's particular statement" is not precise enough to serve as an axiom.). As such, with a little more legwork, it can be proven that any logical system robust enough to accommodate arithmetic must necessarily contain facts that are true within the system but cannot be proven or disproven within the system. The importance of this result cannot be understated, as it upended the entire philosophy of mathematics. {{w|David Hilbert}}'s famous proclamation "We must know, we will know" is simply incorrect. ... Either that, or (ironically) Gödel used an "inconsistent" or "incomplete" system to produce his result.

The title text suggests that Gödel should perform such an analysis on different branches of mathematics, by calculating the average of all the fields' theorems' Gödel numbers. This is nonsensical for a number of reasons:
:1) Gödel is long dead, and dead people can't write articles;{{Dubious}} - see [[599: Apocalypse]]
:2) Gödel numbers grow very large very quickly, and depend heavily on the specific values assigned to each logical operator. Therefore the results could be manipulated simply by changing the numbering order of each operator;
:3) It may be very hard to gather all theorems in a field, or even a representative sample;
:4) Different fields of science, like biology or human behaviour, may not be able to write their theorems in the mathematical language of Gödel's incompleteness theorem
If anyone were to attempt this form of analysis, it would be an example of the bad data science described in the caption.

==Transcript==
:[Cueball holds a hand up to his chin while he ponders the contents of what may be a whiteboard. There are five general lines of unreadable scribbling on the board, and between the two bottom lines, there is a square frame to the right with another scribble to the left. Cueball's thoughts are shown above him in a large thought bubble.]
:Cueball's thinking: If I assign numbers to each of these things, then it becomes '''''data''''', and I can do '''''math''''' on it!

:[Caption beneath the panel:]
:The same basic idea underlies Gödel's Incompleteness Theorem and all bad data science.

{{comic discussion}}
[[Category:Math]]
[[Category:Comics featuring Cueball]]
[[Category:Logic]]

1433: Lightsaber

2022-05-04T00:03:12Z

Xyl: Undo revision 234815 by X. K. C. D. (talk)

{{comic
| number = 1433
| date = October 13, 2014
| title = Lightsaber
| image = lightsaber.png
| titletext = A long time in the future, in a galaxy far, far, away, astronomers in the year 2008 sight an unusual gamma-ray burst originating from somewhere far across the universe.
}}

==Explanation==
This comic references a [http://www.youtube.com/watch?v=WDnoczxzQyg scene] from the third theatrically-released ''{{w|Star Wars}}'' movie, ''[[wikia:c:starwars:Return of the Jedi|Return of the Jedi]]'', wherein [[wikia:c:starwars:Darth Vader|Darth Vader]] confronts his son, [[wikia:c:starwars:Luke skywalker|Luke Skywalker]], who had recently surrendered to [[wikia:c:starwars:Galactic Empire|Imperial]] soldiers. In the movie, Vader notes that Luke has constructed [[wikia:c:starwars:Luke Skywalker's lightsaber|a new lightsaber]] following the loss of his [[wikia:c:starwars:Luke skywalker#Lightsabers|original]] during their [[wikia:c:starwars:Duel on Cloud City|duel on Cloud City]] (Luke Skywalker's original lightsaber actually having been [[wikia:c:starwars:Anakin skywalker|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 {{w|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 {{w|Star Wars (film)|Star Wars}} {{w|Star Wars opening crawl|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!

==Transcript==
:[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!!''

{{comic discussion}}
[[Category:Star Wars]]
[[Category:Physics]]

2612: Lightsabers

2022-05-04T00:01:22Z

Xyl: Undo revision 235158 by X. K. C. D. (talk)

<noinclude>''For the comic named "Lightsaber", see [[1433: Lightsaber]].''</noinclude>
{{comic
| number = 2612
| date = April 27, 2022
| title = Lightsabers
| image = lightsabers.png
| titletext = A lot of Jedi romances start with this turning into a Lady and the Tramp spaghetti situation.
}}

==Explanation==
{{incomplete|Created by a MAGNETICALLY CONFINED PLASMA-SABER REACTOR - Please change this comment when editing this page. Do NOT delete this tag too soon.}}
A {{w|lightsaber}} is a fictional beam-like sword weapon used by members of the {{w|Jedi}} order and the {{w|Sith}} in the ''{{w|Star Wars}}'' franchise. This comic shows a lightsaber fight starting between two [[Cueball]]-like Jedi, one already presenting their blade in challenge and the second activating theirs in response. When the first strike is made between the two lightsabers, they meld together with a bloop sound, like the beams are made of a liquid. The two light beams then remain stuck to each other. In in-universe "technical documents", lightsabers are said to be made from magnetically-confined plasma, so perhaps the magnetic fields which were projected from each hilt have merged instead of repelling (or presenting as mutually impervious) as is usually expected.

(This scene actually looks a lot like what happens between Harry Potter and Voldemort's wands in the end of the fourth book, the {{w|Harry Potter and the Goblet of Fire|''Goblet of Fire''}}. Here two spells hit each other and connect the two wands, the wand holders then unable to release or disconnect the wands.)

First the left Jedi, then the right, shakes the hilt, trying to break the bond. When this does not succeed, the right Jedi then deactivates his lightsaber in an attempt to end the connection. This causes the retraction of the entire double-sized light beam into the handles (as seen in the movies), causing both of the Jedi to be drawn together until their heads bonk, forcefully enough to render them both unconscious. The connected lightsaber handles lie next to them on the ground.

The title text implies that such events are how {{w|Jedi}} romances start, comparing it to the famous "spaghetti scene" from the 1955 Disney animated movie ''{{w|Lady and the Tramp}}'' where the two titular characters unintentionally kiss after sharing a strand of spaghetti. In the Old Republic, Jedi were forbidden from entering into romantic relationships (and discouraged from forming attachments in general), but in the pre-Disney ''Star Wars Legends'' continuity of the {{w|Star Wars in other media|Expanded Universe}}, {{w|Luke Skywalker}} and {{w|Mara Jade}} first met while fighting in the aftermath of the fall of the Empire, and then developed a romantic relationship.

Star Wars is a [[:Category:Star Wars|recurring theme]] on xkcd, and lightsabers have been prominently featured before in, for instance, [[1397: Luke]] and [[1433: Lightsaber]], where the problem with the physics of a light beam as a sword is shown. But in general light does not interact with light as {{w|photons}} are {{w|bosons}} and can thus pass through each other. Interference, yes, but two pure light beams cannot collide and bounce back as when two lightsabers collide. Also as the comic Lightsaber mentioned above shows, there is no compatible real-world way of confining a beam of light, making it stop after about a meter (or anywhere){{Dubious}} - see {{w|Optical cavity}}.

==Transcript==
:[Two Cueball like Jedi are engaging each other in a duel using lightsabers over 12 panels of equal size, with sound effects as the only sound. In the first panel the left Jedi has his lightsaber extended holding it in both hand pointing towards the other, who at this time is just turning his lightsaber on.]
:''Tssssss''
:Click

:[Almost same position of the Jedi, but the right Jedi's lightsaber has now extended, making a sound. He is holding it up near his head in both hands]
:''Tsss''

:[Then they run towards each other and swing their lightsabers towards each other, two small arcs indicating the swing of the lightsabers.]

:[The two beams hit each other and connects at the middle in a big bloop of light, with drops of "light" jumping off both above and below the connected lightsabers. Both Jedi still holds on to their handles with both hands. A loud sound comes out of the connection:]
:''Bloop''

:[The Jedi stands still holding their handles. The beam is now forming a bow between the two handles.]

:[The left Jedi violently shakes his handle causing a wave to travel down the beam towards the right Jedi.]
:Shake shake

:[The right Jedi shakes his handle and well and another wave travels the opposite direction towards the left Jedi.]
:Shake shake

:[Back to the bow of light between them, but the beam is visibly still shaking, but no wave is traveling any longer.]

:[Same setting but the shaking has stopped. The right Jedi turns his lightsaber off on his handle with a sound:]
:Click

:[The beam of light is retracted quickly into the handle of the Jedi turning his lightsaber off. So quickly that the two Jedi, still holding on to their handles are pulled up in the air and towards each other as the sound of the beam turning off is heard. Lines indicate their movement and shadows on the ground beneath them indicate they are in the air.]
:''Zhhhiiiip''

:[When the beam is completely retracted the two handles collide and so do the heads of the two Jedi with a loud sound. They still hold on to their handles with both hands. They still hang in the air with shadows on the ground beneath them.]
:''Bonk''

:[In the final panel the two Jedi lie unconscious on the ground with their heads towards each other and with their arms stretched out towards each other. The connected handles lie between them.]

{{comic discussion}}

[[Category:Comics featuring Cueball]]
[[Category:Multiple Cueballs]]
[[Category:Star Wars]]
[[Category:Fiction]]