explain xkcd - User contributions [en]

Talk:135: Substitute

2022-11-09T23:53:00Z

172.69.34.30:

[[User:Rikthoff|Rikthoff]] ([[User talk:Rikthoff|talk]]) The issue date is off, as i can't find a create date for the image. Can anyone fix?

:Yes, I've fixed the date on the page. [[User:Lcarsos|lcarsos]] ([[User talk:Lcarsos|talk]]) 15:30, 14 September 2012 (UTC)

1. It takes the raptor 25m/s / 4m/s^2 = 6.25s to reach it's top speed, during which I can run 6.25s * 6m/s = 37.5m. Add on my 40m head start, and I can reach a spot 77.5m away from the raptor before he gets me. In the same time, the raptor can run 4m/s^2 * (6.25s)^2 / 2 = 78.125m. I'm eaten before he's fully up to speed.
Therefore, I have to solve for when the raptors location, r(t) = 4m/s^2 * t^2 /2 - 40, and my location, m(t) = 6m/s*t, are equal. Dropping units, we get 2t^2 -40 = 6t, or 2t^2 - 6t - 40 = 0. Dividing by 2 I get t^2 - 3t - 20=0. Using the quadratic equation, I get (3 +/- sqrt(89))/2, roughly equal to 6.217s and -3.217s. Plugging that back into m(t), I get 37.302m for my terminal run. [[User:Blaisepascal|Blaisepascal]] ([[User talk:Blaisepascal|talk]]) 22:18, 14 September 2012 (UTC)

I don't think there is enough information to solve the second problem, because you don't know how fast the non-injured raptors go. Unless you take that information from the first problem. But then, how fast does the wounded raptor accelerate? You would have to find the angle where the wounded and the closest non-wounded raptor would meet you at the same time. [[Special:Contributions/213.127.132.140|213.127.132.140]] 17:17, 5 September 2013 (UTC)

With all three raptors and you running at top speeds, I don't think you get caught by the injured raptor and uninjured raptor at the same time. I believe that you must run directly towards the wounded raptor and the two non-injuried raptors will reach you simultaneously before you and the injured raptor meet, and you cannot do better. After all, you can try to run directly away from an uninjured raptor, but you will lose ground to it at a rate of 25-6=19 m/s (but, it is worst for the other uninjured raptor). By running directly at the injured raptor, you lose ground from it at the rate of 10+6=16 m/s. However, if you can accelerate at a rate far above the raptors, I think you could change directions so fast that one raptor could not catch you. However, I am not sure you can keep away from all three indefinitely. --DrMath 04:01, 24 October 2013 (UTC)

I did the math and if you run directly towards the wounded raptor it will catch you before the uninjured raptors do. (It would be better to run directly away from the uninjured raptor than it would be to run towards it, but that still not the answer.) As you would cover ~8m if you ran at the wounded raptor and survive for ~1.33s where as the uninjured raptors (assuming they rundirectly towards the point you meet the wounded raptor would take ~2.9s to reach this point. [[Special:Contributions/162.158.178.116|162.158.178.116]] 00:35, 8 October 2016 (UTC)

For 1 and 2 the solution depends on whether the raptors can accelerate at 2m/s, or they actually increase their speed at this rate. If they just accelerate, It should be possible to do tight circles, and even wind yourself slowly towards another location. I believe this is possible even treating yourself and the raptors as point masses. [[Special:Contributions/2.102.215.18|2.102.215.18]] 13:19, 17 July 2013 (UTC)

This could also be a parody of Snape substituting for Lupin (Harry Potter and the Prisoner of Azkaban) in the Defense against Dark Arts class. Snape assigns homework on werewolves, in the hopes of one of the students connecting the dots. Here, Randall might be trying to get the students to suspect that Mrs.Lenhart might be a raptor (out of sympathy, or just being a classhole?). Also [[155]]. [[Special:Contributions/208.124.118.63|208.124.118.63]] 18:58, 1 October 2013 (UTC)BK201

There is a problem with the test, as Mr. Munroe wrote it: Question #1 says that a raptor has a top speed of 25 m/s, but question #3 says "Remember, raptors run at 10 m/s...". Furthermore, question #2 says an injured raptor runs at 10 m/s.
:The way I resolved that was that raptors wouldn't be able to run straight long enough to reach their top speed inside of a building. [[Special:Contributions/108.162.237.161|108.162.237.161]] 23:53, 27 April 2015 (UTC)

BTW, the answer to question #2 is: run straight toward the injured raptor. The uninjured raptors will run toward you and the injured raptor. Just as you get close to the injured one, slide under his legs. Because he is injured, the uninjured raptors will feast on him instead of you. [[Special:Contributions/173.245.55.227|173.245.55.227]] 20:58, 13 December 2013 (UTC)

:This presumes the raptors are cannibalistic. -Pennpenn [[Special:Contributions/162.158.2.221|162.158.2.221]] 05:30, 15 June 2015 (UTC)

::In the original Jurassic park book, the little children get chased through the hatchery, and they try to use a baby raptor to distract the raptors chasing them, but the small raptor gets ripped to shreds. Raptors are merciless and horrible beings. Randall is right to hate them.[[User:RedHatGuy68|RedHatGuy68]] ([[User talk:RedHatGuy68|talk]]) 01:28, 29 October 2015 (UTC)

::I solved it by being a t-rex and just eating the raptors. It's amazing how many math problems become easier when you're a t-rex. [[Special:Contributions/162.158.255.69|162.158.255.69]] 23:29, 16 September 2015 (UTC)

:::So many problems become easier it seems by becoming a T-Rex.

What if they're utahraptors or nanotyranus [[Special:Contributions/108.162.245.120|108.162.245.120]] 07:14, 13 October 2016 (UTC)

Question 3 is inaccurate: Using the knowledge gleaned from the movie, we can only assume raptors can open some doors. i.e., those with lever handles. Given their anatomy, it is unlikely that they would achieve proficiency with the more standard round-knob-based doors. --Electro-- [[Special:Contributions/108.162.221.130|108.162.221.130]] 07:13, 9 September 2017 (UTC)

Should this be in 'comics featuring Miss Lenhart'? The comic does not show her, although it does mention her.

2694: Königsberg

2022-11-05T07:03:18Z

172.69.34.30: /* Explanation */ spurious period

{{comic
| number = 2694
| date = November 4, 2022
| title = Königsberg
| image = konigsberg_2x.png
| imagesize = 448x343px
| noexpand = true
| titletext = At first I thought I would need some gold or something to pay him, but then I realized that it was the 18th century and I could just bring a roll of aluminum foil.
}}

==Explanation==
{{incomplete|Created by a WOLF, TWO GOATS, AND THREE BAGS OF GRAPH NODES. Do NOT delete this tag too soon.}}

[[File:Konigsberg bridges.png|frame|right|{{w|Königsberg}}, Prussia in Euler's time, showing the Pregel river and its seven bridges. The Baltic port city is now Kaliningrad, a Russian exclave.]]

This comic is about the {{w|Seven Bridges of Königsberg}}, a seminal {{w|graph theory}} problem solved by the famous mathematician {{w|Leonhard Euler}}.[https://www.maa.org/press/periodicals/convergence/leonard-eulers-solution-to-the-konigsberg-bridge-problem] Graphs are a data structure found in most solutions to algorithmic problems in computer science. The problem launching graph theory was to devise a path through the city that would cross each of the seven bridges exactly once, without crossing the river forks any other way. In 1736, Euler proved that there was no such possible path. This result is considered to be the first theorem of graph theory and the first proof in the theory of networks[http://www-personal.umich.edu/~mejn/courses/2004/cscs535/review.pdf] — a subject now generally regarded as a branch of {{w|combinatorics}} — and presaged the development of {{w|topology}}. Combinatorial problems of other types had been considered since antiquity.

[[Cueball]] attempts to cheat on the final exam in his algorithms class by traveling back in time to commission the construction of an eighth bridge before Euler could learn of the problem, allowing a trivial solution that would remove the rationale for further analysis. He hopes that this would alter his present-day timeline in such a way that the test becomes easier because graph theory might never have been developed.

With the addition of the eighth bridge, it becomes possible to create a path that crosses each bridge exactly once, starting at the north bank and ending on the eastern island (or vice-versa). However, there would remain no way to traverse each bridge exactly once and return to your starting point, because the altered graph would have an {{w|Euler trail}} but not an {{w|Euler cycle}}. Thus, the problem might still have been sufficiently interesting to spark Euler's curiosity. Adding a ninth bridge connecting the north bank to the east island would render the problem completely trivial. Without the seven bridges problem, Euler could have focussed on a different foundation for graph theory, possibly making an even harder examination in Cueball's time.

The title text alludes to the fact that ordinary {{w|aluminum foil}}, which was not commercially available until 1911, would have been a tremendously valuable curiosity in the 18th century, which didn't even have {{w|tin foil}}. Aluminium itself was a highly priced metal before the 1880s, when methods were developed to cheaply refine it. Famously, the {{w|Washington Monument}} was constructed with a tip made of pure aluminum due to its great value and conductive capacity. Aluminum had not even been extracted in its pure form at the time of Euler, and was only known in compounds such as {{w|alum}}, so it would have been unique and exotic.

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

:[Cueball, standing next to two men wearing wigs, pointing with a pointer at a map showing the seven bridges problem, with an extra bridge added in dashed lines]
:Cueball: Lord Mayor of Königsberg, I will reward you handsomely if you construct this bridge before my friend Leonhard arrives.

:[Caption below the panel:]
:I tried to use a time machine to cheat on my algorithms final by preventing graph theory from being invented.

{{comic discussion}}
[[Category:Comics featuring Cueball]]
[[Category:Comics featuring real people]]
[[Category:Math]]
[[Category:Programming]]

No One Was Hurt

2022-10-25T02:07:05Z

172.69.34.30: /* Transcript */ cats

{{comic
| date = July 6, 2022
| title = No One Was Hurt
| image = no_one_was_hurt.png
| titletext = See how the smoke obscures things so you don't see the approaching tornado until the firework streamers start to swirl right before the lightning hits the launcher. Thank God Cousin Ed was filming in slow motion. And, uh, that no one was hurt.
| lappend = 404
}}

==Explanation==
{{incomplete|Created by a FIREWORK TORNADO - Please put citations into context better. Please change this comment when editing this page. Do NOT delete this tag too soon.}}
This comic was originally uploaded normally on the [[xkcd]] website as number [[2642]], before being taken down and replaced by [[2642: Meta-Alternating Current]]. This was most likely done in response to the wave of shootings across the country during the celebrations, including {{w|Highland_Park_parade_shooting|a deadly mass shooting at the parade in Highland Park, Illinois}} which was recorded on video where people were injured and killed. So, a comic about 4th of July celebrations where someone could have been hurt can be seen as in bad taste.

[[Ponytail]] is about to show [[Cueball]] and [[Megan]] a video of a dramatic accident from a {{w|4th of July}} celebration with {{w|fireworks}}, in which nobody ended up harmed. Randall suggests that being told nobody got hurt implies such a video will be particularly interesting or exciting. This is because if the disclaimer is needed, it implies that there was a certain degree of peril created by the events in the video, and this would typically create excitement for the viewer. Here is [https://www.youtube.com/watch?v=Y5QBiZIxWbA&ab_channel=BYUUniverse an example video] in which probably no one was hurt.

The title text describes a particularly dramatic fireworks show interrupted by a tornado and thunderstorm, the joke being that the speaker seems more appreciative that it was recorded in slow-motion video than that nobody was harmed.

=== Citations ===

The Wikipedia article {{w|Mass shootings in the United States|"Mass shootings in the United States"|m|}} lists mass shootings in the USA, {{w|List_of_mass_shootings_in_the_United_States_in_2022|"List of mass shootings in the United States in 2022"}} more thoroughly lists those that happened in 2022, {{w|Highland Park parade shooting|"Highland Park parade shooting"}} details the specific shooting in Illinois, and {{w|Mass shootings in the United States|"Mass shootings in the United States"}} discusses US mass shootings instead of just listing them. The [https://www.gunviolencearchive.org/reports/mass-shooting Gun Violence Archive] website tracks mass shootings in the USA.

==Transcript==
:[Ponytail is showing her phone to Cueball and Megan.]
:Ponytail: Okay, first of all, no one was hurt...
:[Caption below the panel]:
:How you know you're about to see a really good 4th of July video

{{comic discussion}}
[[Category:Deleted comics]]
[[Category:Extra comics]]
[[Category:Comics featuring Cueball]]
[[Category:Comics featuring Ponytail]]
[[Category:Comics featuring Megan]]

No One Was Hurt

2022-10-25T02:06:31Z

172.69.34.30: /* Transcript */ ce

No One Was Hurt

2022-10-25T02:06:16Z

172.69.34.30: /* Transcript */ done

{{comic
| date = July 6, 2022
| title = No One Was Hurt
| image = no_one_was_hurt.png
| titletext = See how the smoke obscures things so you don't see the approaching tornado until the firework streamers start to swirl right before the lightning hits the launcher. Thank God Cousin Ed was filming in slow motion. And, uh, that no one was hurt.
| lappend = 404
}}

==Explanation==
{{incomplete|Created by a FIREWORK TORNADO - Please put citations into context better. Please change this comment when editing this page. Do NOT delete this tag too soon.}}
This comic was originally uploaded normally on the [[xkcd]] website as number [[2642]], before being taken down and replaced by [[2642: Meta-Alternating Current]]. This was most likely done in response to the wave of shootings across the country during the celebrations, including {{w|Highland_Park_parade_shooting|a deadly mass shooting at the parade in Highland Park, Illinois}} which was recorded on video where people were injured and killed. So, a comic about 4th of July celebrations where someone could have been hurt can be seen as in bad taste.

[[Ponytail]] is about to show [[Cueball]] and [[Megan]] a video of a dramatic accident from a {{w|4th of July}} celebration with {{w|fireworks}}, in which nobody ended up harmed. Randall suggests that being told nobody got hurt implies such a video will be particularly interesting or exciting. This is because if the disclaimer is needed, it implies that there was a certain degree of peril created by the events in the video, and this would typically create excitement for the viewer. Here is [https://www.youtube.com/watch?v=Y5QBiZIxWbA&ab_channel=BYUUniverse an example video] in which probably no one was hurt.

The title text describes a particularly dramatic fireworks show interrupted by a tornado and thunderstorm, the joke being that the speaker seems more appreciative that it was recorded in slow-motion video than that nobody was harmed.

=== Citations ===

The Wikipedia article {{w|Mass shootings in the United States|"Mass shootings in the United States"|m|}} lists mass shootings in the USA, {{w|List_of_mass_shootings_in_the_United_States_in_2022|"List of mass shootings in the United States in 2022"}} more thoroughly lists those that happened in 2022, {{w|Highland Park parade shooting|"Highland Park parade shooting"}} details the specific shooting in Illinois, and {{w|Mass shootings in the United States|"Mass shootings in the United States"}} discusses US mass shootings instead of just listing them. The [https://www.gunviolencearchive.org/reports/mass-shooting Gun Violence Archive] website tracks mass shootings in the USA.

==Transcript==
:[Ponytail is showing her phone to Cueball and Megan.]
:Ponytail: Okay, first of all, no one was hurt...
:[Caption below the panel]: How you know you're about to see a really good 4th of July video

{{comic discussion}}
[[Category:Deleted comics]]
[[Category:Extra comics]]

2683: Fan Theories

2022-10-25T02:04:48Z

172.69.34.30: /* Transcript */ done

{{comic
| number = 2683
| date = October 10, 2022
| title = Fan Theories
| image = fan_theories_2x.png
| imagesize = 267x318px
| noexpand = true
| titletext = The universe fandom is great. Such sweet and enthusiastic people.
}}

==Explanation==

A fan theory is an unofficial hypothesis about fictional work from enthusiasts instead of the official authors. Fan theories may include {{w|Canon (fiction)|non-canonical}} background information for, or continuations of, official narratives. Since humanity is not the "author" of the universe, all thoughts and writings on the nature of the universe are, almost by definition, non-canonical fan ideas.

In this comic, [[Cueball]] refers to scientific hypotheses as "fan theories." Scientists might consider this as undervaluing their work, because scientific hypotheses are usually the result of much more serious research than the authorship of fiction.{{Citation needed}} Charismatic cranks often obtain undeserved recognition for supposedly scientific hypotheses, so being lumped in with charlatans or pseudoscientists could be perceived as insensitive to rigorous scientists. Once again, [[Randall]] has attempted to devise a new way to annoy scientists. However, many if not most professional scientists are aware of similarities between hypotheses pertaining to fiction and non-fiction.

By referring to rigorous scientific studies as "fan theories" [[Randall]] is also elevating the experience of fandom. Though they are typically not supported by research institutions, tenured faculty positions, or grant funding, fandom communities often demonstrate a high degree of skill in literary criticism including evidence gathering, philosophical interpretation, and generative writing. This continues the trend of building connections between disciplines in STEM, social science, and the humanities.

This comic appeared a few days after renewed suggestions that life may exist [https://www.space.com/saturn-moon-enceladus-ocean-phosphorus within one of Saturn's moons].

The title text may be facetious, having to do with unwelcoming or inconsiderate {{w|fandom}}s (or scientists who are annoyed at being called "fans of the universe"), or it could be sincere.

==Transcript==
:[Ponytail, Cueball, White Hat, and Megan standing in a line. Cueball has his hand raised, and Megan has hands balled into fists, exasperated.]
:Cueball: But according to leading fan theories, Jupiter's moons may harbor subsurface oceans.
:Megan: Will you ''please'' stop calling them that?

:[Caption below the panel:]
:How to annoy scientists: refer to all hypotheses as "fan theories"

{{comic discussion}}
[[Category:Science]]
[[Category:Astronomy]]
[[Category:Comics featuring Ponytail]]
[[Category:Comics featuring Cueball]]
[[Category:Comics featuring White Hat]]
[[Category:Comics featuring Megan]]

2677: Two Key System

2022-10-25T02:03:42Z

172.69.34.30: /* Transcript */ done

{{comic
| number = 2677
| date = September 26, 2022
| title = Two Key System
| image = two_key_system_2x.png
| imagesize = 645x316px
| noexpand = true
| titletext = Our company can be your one-stop shop for decentralization.
}}

==Explanation==
As an allegory, the comic relates the results of software development to the reputed safeguards of nuclear missile launch systems.

Such precautions include the {{w|Two-man rule|need for two independent operators for authorization}}, to prevent honest mistakes or the rogue actions of lone-actors. This may include the use of a {{w|nuclear briefcase}}, where a verification process involves secondary authority figures other than the primary one. However, this illustration more clearly refers to the kind of procedure used at a launch site where two duty officers each need to turn their respective keys simultaneously. The physical distance between the keys ensures that an individual cannot turn both keys similtaneously, or initiate the sequence without the second person.

In relation to software development, the inconvenience prevented by such precautions (like account passwords and {{w|two-factor authentication}}) has prompted the development of methods to make the process easier (like {{w|autofill|autofilling}} passwords or website cookies keeping a user logged in for multiple visits). Similarly, the system in the comic is made more convenient by using a dual key-turner that circumvents the need for two users to turn the keys.

And thus we find out that the thing used to make the safeguards less of a nuisance actually defeats the purpose of the safeguards. As with website passwords, where the use of a computer or device by someone else could allow ''them'' to use the autologin capabilities, or even to view all passwords used locally and take away for their own use, the whole point of the deliberately included security factor has been negated. It was only the perceived need for two independent operators that created the initial situation of requiring two separated keys, or indeed any keys at all!

Hence, after a further cycle of development, in order to restore the security of the two-key system, the two-key turning device (rather than being removed or made unworkable) is provided for use but ''only'' if it can be removed from a secure cabinet (labelled as giving access to the 'key turner', much as the original unit was labelled as giving access to a missile) with the requirements to open it being… …two seperate keys to be used at the same time! This could be seen as the same as {{w|password manager}}s being introduced, either as a part of a browser or third-party add-ons, which automatically provide the user's passwords for any given access attempt but only when they are given a password (or other security factor) themselves.

And so, rather than removing a 'problem', a new safeguard is added which does the exact same thing as the original, the possible nuisance (but hopefully also the necessary element of security) included.

Password management, as a process, is substantially similar to key management: Common failure-modes for both passwords and keys, include forgetting your own long-term passwords (especially if you changed computers after asking your computer to remember your passwords for you) which is functionally similar to misplacing your keys, or tending to use just a single password or key for every lock (which, if ever compromised in one situation, may lead to being compromised across many others). A Password Manager can reduce such issues, as it can be capable of 'spitting out' or transfering login details at will and letting you use many different passwords (even generating and using the kinds of passwords nobody should be able to guess, [[936: Password Strength|or remember!]]) across your many different websites, etc. But this passkey storage must itself be secure, and so should be functionally accessible perhaps only through use of a 'master passkey' or some other kind of authentication process, which may be subject to the same issues of forgetting, copying, or theft. Similarly, a central lockbox full of keys (such as those used at some car dealerships), can make handling multiple keys much easier, while introducing a single point of failure in the event that lockbox is illicitly accessed. Various forms of {{w|multi-factor authentication}}, plus auxiallary authentication methods for password recovery/reset, go some way to alleviate these challenges, at the expense of further intermediary steps and hardware requirements; but the balance between ease of use and security is never quite so simple and universal.



The title text mentions a one-stop-shop for decentralization. The drive to make use of one-stop-shops (such as a website aggregating searches for the best insurance) and ''also'' to decentralize (in this case not relying upon any one vendor, even that single aggregator who might actually not be the best aggregator) is another self-contradiction — because a one-stop-shop is by definition centralized.

The comic being posted on September 26th may be a reference to Stanislav Petrov correctly rejecting the false detection of an incoming nuclear missile strike from the US on September 26th, 1983. [[2052: Stanislav Petrov Day]]

For a related xkcd on software cycles, see [[2044: Sandboxing Cycle]].

==Transcript==
{{incomplete transcript|Do NOT delete this tag too soon.}}
:[Caption above the panel:]
:All software development, eventually

:[Cueball is talking, while pointing to a drawing. It represents two keys, pointing to Cueball and Ponytail turning keys at either end of a missile launch system - a large anonymous cabinet except for a picture of a missile upon it]
:Cueball: We've installed a two-key system to prevent accidental missile launches.

:[An arrow is pointing to the next panel:] Soon

:[The drawing now represents a device with two inward-facing keys connected by a long bar with a further handle, and below that is shown how it is used with a cabinet such as above to let Cueball to activate the unit by himself]
:Cueball: We've developed a dual-turner device to allow a user to efficiently turn multiple keys.

:[An arrow is pointing to the next panel:] Soon

:[The drawing now represents two keys, pointing to Cueball and Ponytail turning keys at either end of a large similarly anonymous cabinet, except for the picture upon it being of the device of panel 2]
:Cueball: We've installed a two-key lock on the dual-turner device to prevent accidental use.

{{comic discussion}}

[[Category:Comics featuring Cueball]]
[[Category:Comics featuring Ponytail]]
[[Category:Programming]]
[[Category:Nuclear weapons]]
[[Category:Computer security]]

2674: Everyday Carry

2022-10-25T02:02:03Z

172.69.34.30: /* Transcript */ done

{{comic
| number = 2674
| date = September 19, 2022
| title = Everyday Carry
| image = everyday_carry_2x.png
| imagesize = 370x310px
| noexpand = true
| titletext = Someday I just know I'm going to encounter a problem that requires 500 flashlights and 700 knives with weird holes in them, and on that day I won't be caught unprepared.
}}

==Explanation==
"EDC" stands for {{w|everyday carry}}, which is a term for tools and other objects intended to be carried around during the course of everyday life. The notion is that a relatively small number of versatile items, designed to be easily portable, can prepare you for a wide variety of possible situations. Typical items include such things as wallets, cell phones, small flashlights, pocketknives and multi-tools. Items specific to a person's occupation, lifestyle, or other needs might also be included.

While the concept of regularly carrying items that you might need is a very old one, the abbreviation "EDC" has come to signify a subculture, [https://www.vox.com/the-goods/2019/7/24/20696487/everyday-carry-reddit-knife-wallet-gun well-represented on the internet] which promotes self-reliance and preparedness for almost any situation. As with so many subcultures, this movement has spawned a thriving market in selling products explicitly intended for "being carried every day". Any internet search will reveal thousands of products, of various levels of quality and utility, marketed to people interested in EDC. Stylized pocketknives, 'tactical' flashlights, and tools purporting to fulfill multiple functions are common examples.

Rather than carefully consider the relative advantages of each of these pieces of gear, Cueball seems to have taken the advertising of such items at face value: he's purchased them all, and attempts to carry them all with him every day. The result is that he has so many items that he not only needs to wear a heavily augmented backpack, he also needs to drag around a cart carrying boxes and a massive bag, presumably filled with the thousands of pieces of gear he's purchased. Such a strategy obviously defeats the original purpose of EDC, which is to select a set of items that's both portable and useful, but such is the result of taking internet marketing literally.

In the title text, he expresses confidence that he'll be vindicated by encountering a situation in which his massive collection of items will be useful. He also makes clear that, having bought ''all'' the items available, his collection is wildly redundant, having hundreds of flashlights and pocketknives. While it's quite common to encounter a situation in which a knife or flashlight is needed (sometimes even two might be useful), a situation where hundreds would be useful is difficult to imagine. One use might be a very dangerous {{w|Live action role-playing game|LARP}} cloud of daggers.

==Transcript==
:[Cueball is standing and straining backwards, dragging a large sack nearly the size as him, with noticeable bulges. It is placed on top of two long, flat boxes on top of a flat, four-wheeled trolley. Motion lines indicate the trolley is rolling towards Cueball and his hands are shaking. Cueball is also wearing a large backpack with multiple compartments. The backpack, boxes and sack are all labelled "EDC"]

:[Caption under the panel:]
:It was hard work collecting all the everyday carry products on the Internet, but now I'm finally ready for anything.

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

2660: Gen Z

2022-10-25T02:01:27Z

172.69.34.30: /* Transcript */ ce

{{comic
| number = 2660
| date = August 17, 2022
| title = Gen Z
| image = gen_z.png
| titletext = Curdled milk, of a peculiar kind, made after a Bulgarian recipe and called "yaghurt," is now a Parisian fad and is believed to be a remedy against growing old. A correspondent who has tried it, says he would prefer to die young. (1905, The Elk Falls Journal)
}}

==Explanation==

Older generations are often confused by the trends and norms of younger people, and this comic aims to contextualize this common situation by placing it in a historical perspective — featuring the usual cast of xkcd in historical garb. White Hat (wearing a white boater) has seemingly just finished introducing a topic of discussion to the rest of the group; he knows the rest of his group will find the topic weird, but is willing to defend Gen Z with the excuse "that's just how they do things." Black Hat is expressing a notion that sounds a lot like [https://www.youtube.com/watch?v=LD0x7ho_IYc juvenoia], and is quick to make sweeping generalizations about the younger group. The other reactions depicted are representative of the broader spectrum of possible responses: either surprised interest or cautious acceptance. There is no evidence that White Boater is correct about how Gen-Z does things.

Neither knee-jerk rejection nor forward-looking sympathy are specifically praised by the main text of the comic, but the example highlighted in the title text seems to imply that Randall would like to emphasize openness to new things.

The title text [https://mobile.twitter.com/xkcd/status/1560020008545165319 quotes] a newspaper from Elk Falls, Kansas, which on May 18, 1905, told of a "Parisian fad". The item was a shortened version of an account which also ran in many other newspapers. In this case, the "fad" is the introduction of {{w|yogurt}} (spelled "yaghurt" in this publication, probably because English spelling of the word was not standardized yet and may have been influenced by the French spelling ("yaourt") and phonology). In the modern day, yogurt is enjoyed as a common food in most [[559: No Pun Intended|cultures]], but in 1905 the concept was bizarre and repulsive to many readers. This shows that things which are dismissed as "strange" because of preconceived notions of a particular group (that curdled milk is necessarily bad) may, in fact, be perfectly acceptable once more context is obtained. It is also worth noting that yogurt was not invented in 1905, but had existed for centuries prior; despite this, the recent introduction to French culture is what prompted its recognition as a nascent "fad". This may be analogized to various fads and trends which {{w|Gen Z}} is embracing which may appear unfounded to members of older generations, but which nevertheless represent acceptance of ideas which did not originate with members of that generation. Randall may have chosen this particular version of the item in part because it omits some of the statements in the longer item, such as that consumption of yogurt could “prolong human life to what is its normal span - a century or so.”

This is not the first comic to identify "modern" complaints or viewpoints as having been present throughout history in various forms (see comics [[1227: The Pace of Modern Life]] and [[1601: Isolation]]).

The humor in making generalizations about people born in specific time periods is also seen in [[973: MTV Generation]], [[1962: Generations]] and [[2249: I Love the 20s]].

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

:[Six individuals in clothing representing early 1900s' American fashion stand in a line. Four of them have speaking roles, from left to right, and two stand in silence, contributing to the feeling of a conversation amongst a crowd gathered around the first speaker]
:Speaker 1 (white brim hat): Now, it may sound strange, but it's how Gen Z is doing things!
:Speaker 2 (wavy hair, dress with belt): Gosh! Is that really true??
:Speaker 3 (dark hat with indent): Ridiculous. It just goes to show what I've been saying about them.
:Speaker 4 (hair in bun, dress with lace hem): Now now, maybe we just need to change with the times.

:[Caption below comic:]
:People ascribing qualities to "Gen Z" have the same energy as small-town salespeople in 1905 talking about what the ladies in Paris are up to.

{{comic discussion}}

[[Category:Food]]
[[Category:Social interactions]]
[[Category:Comics featuring White Hat]]
[[Category:Comics featuring Hairbun]]
[[Category:Comics featuring Megan]]

2667: First Internet Interaction

2022-10-25T01:59:38Z

172.69.34.30: /* Transcript */ done

{{comic
| number = 2667
| date = September 2, 2022
| title = First Internet Interaction
| image = first_internet_interaction.png
| titletext = To that stranger on the KOOL Tree House chat room, I gotta hand it to you: You were, ultimately, not wrong.
}}

==Explanation==

In this comic, [[Cueball]], very likely as an autobiographical representation of [[Randall]], describes to [[Megan]] the first time he interacted with a group of people unknown to him over the internet; in an {{w|AOL|AOL}} chat room for children called the "KOOL Tree House chat room" in 1993, when Randall was about nine years old. He read a discussion about {{w|Green Day}}, asked who they are, and was told that not knowing was a serious problem. As Megan says, judging people for lack of pop culture knowledge has remained typical online behavior.

Green Day is an American rock band formed in the East Bay of California in 1987. In 1993, they were still known merely as an independent punk band, and a year away from releasing their major-label debut album ''{{w|Dookie}}'', their first mainstream success. Anyone, especially a nine year-old, not recognizing the band in 1993 would be perfectly normal. After 1993, Green Day would go on to be a widely popular and influential rock band with many acclaimed albums.

This initial online social interaction was a significant formative experience for Cueball, molding his online behavior ever since, in that it still causes him to consider his correspondents' perspectives when communicating. The social dynamics at play are reminiscent of the mathematics of others' perspectives described in [[1053: Ten Thousand]]. Relating the personal experience of an oversized effect from a casual insult is humorous because the extent to which early experiences affect people can be both ironic and profound.

The title text indicates Cueball agrees with the reply to the question. This is humorous because it is effectively Cueball admitting that something is very wrong with him, possibly coincidental with and unrelated to knowing that specific piece of trivia. Alternatively, Cueball could have come to believe Green Day is culturally important. If this story is autobiographical, Randall could have hence become a Green Day fan, or at least acquired more than a passing knowledge of their {{w|œuvre}}, recently mentioning their song "{{w|American Idiot (song)|American Idiot}}" in [[2665: America Songs]].

==Transcript==
:[First panel, Megan and Cueball talking]
:Cueball: You know,
:Cueball: I remember the first thing anybody ever said to me on the internet.
:Megan: Yeah?

:[Second panel, part-height to accomodate Cueball's narration above and the memory of a scene below that features 'Young Cueball', with a mop-head of hair, knelt atop a chair to use a computer with CRT and keyboard on the desk, cabled down into a floor-standing minitower case below]
:Cueball (narrative): I was in an AOL Kids chat room in 1993.
:Cueball (narrative): People there kept using a name I didn't recognise.
:Cueball (narrative): After a while I asked what it was.
:Young Cueball (via the use of the keyboard): W... H... O...  I... S...  G... R...

:[Third panel, close-up of Cueball's adult head, continuing the framing conversation]
:Cueball: Someone replied.
:Cueball: "If you don't know who Green Day is, you have a serious problem."
:Cueball: And that was it. My first virtual interaction.

:[Fourth panel, continuing the conversation, Megan and Cueball now seen walking rightwards as they speak]
:Megan: In some ways, the Internet has changed surprisingly little in the last 30 years.
:Cueball: Every time I reply to someone, I think
:Cueball: What if this is their Green Day moment?

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


[[Category:Comics featuring Megan]]
[[Category:Comics featuring Randall Munroe]] 
[[Category:Music]]

2685: 2045

2022-10-25T01:59:07Z

172.69.34.30: /* Transcript */ done

{{distinguish|2045: Social Media Announcement}}
{{comic
| number = 2685
| date = October 14, 2022
| title = 2045
| image = 2045_2x.png
| imagesize = 350x457px
| noexpand = true
| titletext = "Sorry, doctor, I'm going to have to come in on a different day--I have another appointment that would be really hard to move, in terms of the kinetic energy requirements."
}}

==Explanation==
{{incomplete|Created by a GIGANTIC NUCLEAR FURNACE (THE SUN) - Please change this comment when editing this page. Do NOT delete this tag too soon.}}

The characters are talking about upcoming total {{w|solar eclipses}}. Partial solar eclipses are fairly frequent (2–5 per year), but total eclipses are less frequent (about every 18 months), and most of them will not be in convenient locations for a particular set of people. Cueball seems to be talking about total eclipses visible in much of North America: {{w|Solar eclipse of April 8, 2024|April 8, 2024}} and {{w|Solar eclipse of August 12, 2045|August 12, 2045}}. (There's also a {{w|annular eclipse}} on October 14, 2023.) Making plans for eclipses is awkward given the uncertainty present for anything else far in the future, such as whether the attendees will have children by then, and whether the technology they are using to keep track of their appointments (Google Calendar in this case) will even still exist over 22 years in the future.

Black Hat claims he can't make it, as he vaguely and obscurely claims he already knows he has "a thing" on August 12, 2045. People do not usually have events scheduled for precise dates that far in the future in their personal calendars and, combined with the fact that Black Hat remembers this date without checking (but also without specifying what he'll be doing then), implies that this could be another of his grand and sinister plans... or he just doesn't want to go. This might also be a reference to an [https://web.archive.org/web/20150524213007/http://www.nytimes.com/1987/08/21/us/washington-talk-reagan-and-the-russians-the-joke-s-on-them.html old Soviet joke].

The title text is someone asking to reschedule a medical appointment to see the eclipse. The eclipse is hard to move because that would require hastening or delaying it by moving the Earth, Moon or Sun, any of which would require vast amounts of energy.{{Citation needed}}

This was published a year before the next eclipse; so, if you're someone who plans things a year in advance, this serves as a reminder to put it on your calendar.

==Transcript==
:[Cueball, a friend also drawn as Cueball, Danish, and Black Hat are standing together. Danish is looking at her phone.]
:Cueball: ...And then after the one in 2024, there's another on August 12, 2045.
:Friend: We're in! We can invite our kids, assuming we have any.
:Danish: I'll create an event. Do you think we'll still be using Google Calendar in 2045?
:Black Hat: Sorry, I'd love to make it, but I have a thing that day.

:[Caption below the panel:]
:It's weird making plans for eclipses.

{{comic discussion}}

[[Category:Astronomy]]
[[Category:Comics featuring Cueball]]
[[Category:Multiple Cueballs]]
[[Category:Comics featuring Danish]]
[[Category:Comics featuring Black Hat]]

2683: Fan Theories

2022-10-25T01:56:41Z

172.69.34.30: done

{{comic
| number = 2683
| date = October 10, 2022
| title = Fan Theories
| image = fan_theories_2x.png
| imagesize = 267x318px
| noexpand = true
| titletext = The universe fandom is great. Such sweet and enthusiastic people.
}}

==Explanation==

A fan theory is an unofficial hypothesis about fictional work from enthusiasts instead of the official authors. Fan theories may include {{w|Canon (fiction)|non-canonical}} background information for, or continuations of, official narratives. Since humanity is not the "author" of the universe, all thoughts and writings on the nature of the universe are, almost by definition, non-canonical fan ideas.

In this comic, [[Cueball]] refers to scientific hypotheses as "fan theories." Scientists might consider this as undervaluing their work, because scientific hypotheses are usually the result of much more serious research than the authorship of fiction.{{Citation needed}} Charismatic cranks often obtain undeserved recognition for supposedly scientific hypotheses, so being lumped in with charlatans or pseudoscientists could be perceived as insensitive to rigorous scientists. Once again, [[Randall]] has attempted to devise a new way to annoy scientists. However, many if not most professional scientists are aware of similarities between hypotheses pertaining to fiction and non-fiction.

By referring to rigorous scientific studies as "fan theories" [[Randall]] is also elevating the experience of fandom. Though they are typically not supported by research institutions, tenured faculty positions, or grant funding, fandom communities often demonstrate a high degree of skill in literary criticism including evidence gathering, philosophical interpretation, and generative writing. This continues the trend of building connections between disciplines in STEM, social science, and the humanities.

This comic appeared a few days after renewed suggestions that life may exist [https://www.space.com/saturn-moon-enceladus-ocean-phosphorus within one of Saturn's moons].

The title text may be facetious, having to do with unwelcoming or inconsiderate {{w|fandom}}s (or scientists who are annoyed at being called "fans of the universe"), or it could be sincere.

==Transcript==
{{incomplete transcript|Do NOT delete this tag too soon.}}
:[Ponytail, Cueball, White Hat, and Megan standing in a line. Cueball has his hand raised, and Megan has hands balled into fists, exasperated.]
:Cueball: But according to leading fan theories, Jupiter's moons may harbor subsurface oceans.
:Megan: Will you ''please'' stop calling them that?

:[Caption below the panel:]
:How to annoy scientists: refer to all hypotheses as "fan theories"

{{comic discussion}}
[[Category:Science]]
[[Category:Astronomy]]
[[Category:Comics featuring Ponytail]]
[[Category:Comics featuring Cueball]]
[[Category:Comics featuring White Hat]]
[[Category:Comics featuring Megan]]

2687: Division Notation

2022-10-20T10:49:29Z

172.69.34.30: /* Explanation */ uncited

{{comic
| number = 2687
| date = October 19, 2022
| title = Division Notation
| image = division_notation_new_2x.png
| imagesize = 235x310px
| noexpand = true
| titletext = Science tip: Scientists hardly ever use the two-dot division sign, and when they do it often doesn't even mean division, but they still get REALLY mad when you repurpose it to write stuff like SALE! ALL SHOES 30÷ OFF!
}}

==Explanation==
{{incomplete|Created by a GROUP OF SCHOOLCHILDREN DIVIDED AMONGST THEMSELVES. Do NOT delete this tazg too soon.}}

This comic pokes fun at some of the ways to write the {{w|Division (mathematics)|division}} operation in math. In this comic, [[Randall]] has used A as the dividend (the number being divided) and B as the divisor (the number that A is divided by). Division is the fourth simplest arithmetic operation in mathematics, after addition, subtraction, and multiplication.[https://plato.stanford.edu/entries/principia-mathematica/#PartIVRelaArit]

The first two of the seven notations shown are the {{w|division sign}} (÷) and the {{w|radix}} used for {{w|short division}} and {{w|long division}} in beginning arithmetic. (Note: the short/long division radix is only used in some countries, and there are [https://en.wikipedia.org/wiki/Long_division#Notation_in_non-English-speaking_countries different notations in the non-English speaking world]). These methods of division are often used by school children because the ÷ sign is what most people use when first learning division, and the short division radix is usually the first algorithm learned for dividing arbitrary dividends, typically starting with the easier abbreviated short division form.

The expression on the third line, A/B, is the way division is usually written in software code. The four simple arithmetic operations in programming usually are +, -, *, /. This one was missing in the first version of the comic. This is most commonly seen in regular mathematics as it somewhat saves space, and is easy to type with the slash key. Additionally, it uses standard {{w|ASCII}} characters instead of sophisticated notation.

The expression on the forth line, a/b, is how division is usually written when typography costs are not in question, in fraction notation. The Unicode character sets provide some specific fractions such as ⅓ as well as some superscript and subscript characters, so someone familiar with it might use it to write fractions such as ²²⁄₇.

The fifth notation is the way division is written in science: the dividend on the top of the expression over the divisor on the bottom under a horizontal line. This is how a {{w|Fraction|fraction}} would be written. It has the advantage of clearly separating the numerator and denominator when they are longer expressions, such as polynomials, without needing to add parentheses. This format is mostly used in written and professionally typeset math, as it can't be typed without something like {{w|MathML}}, {{w|LaTeX}} or HTML tables.

The sixth notation uses a negative exponent. The exponent -1 is equivalent to {{w|Multiplicative inverse|reciprocation}}. It can be used to keep the entire expression on one line. Note that ab-1 is equal to a/b. This format is often used to express physical units.

The final form of notation declares a function. The writer defines a new function, F, that takes in the parameters A and B, before listing out the function's definition (trailing off in increasingly smaller text). Randall warns the reader they should escape while they still can, because both the function itself and the math environment as a whole are going to get relatively tedious. Integer division can be defined in terms of multiplicative inequalities and the remainder, or modulo ('%' in Python), operator. This situation is likely to occur in abstract algebra, where one might have to define what "division" means for two elements of a mathematical object such as a group, ring, or magma. One example would be an object G, such that, for two elements A and B of G, "A divided by B" is defined as an element C such that CB=A, or alternatively as an element C such that BC=A. These definitions will differ if multiplication in G is not commutative. Furthermore, if such a C is not unique, the function F(A,B) will need to include a method to select a unique value for "A divided by B" for each A and B. Thus, the F(A,B) in the comic might not even refer to a uniquely defined operation, but simply to the property of a function F(A,B) that is a valid division operation on G, given some definition of division.

The title text recommends distinguishing ÷ from %.

==Transcript==
{{incomplete transcript|Do NOT delete this tag too soon.}}
:Division notation
:A÷B
:B(Ā Schoolchild.
:A/B Software engineer.
:A⁄B Normal person or Unicode enthusiast.
:A over B Scientist.
:AB-1 Fancy scientist.
:F(A, B) such that F(G)= (text getting smaller) Oh no, run

{{comic discussion}}

[[Category:Math]]
[[Category:Science]]
[[Category:Programming]]
[[Category:Science tip]]

2687: Division Notation

2022-10-20T10:39:57Z

172.69.34.30: /* Explanation */ ce

{{comic
| number = 2687
| date = October 19, 2022
| title = Division Notation
| image = division_notation_new_2x.png
| imagesize = 235x310px
| noexpand = true
| titletext = Science tip: Scientists hardly ever use the two-dot division sign, and when they do it often doesn't even mean division, but they still get REALLY mad when you repurpose it to write stuff like SALE! ALL SHOES 30÷ OFF!
}}

==Explanation==
{{incomplete|Created by a GROUP OF SCHOOLCHILDREN DIVIDED AMONGST THEMSELVES. Do NOT delete this tazg too soon.}}

This comic pokes fun at some of the ways to write the {{w|Division (mathematics)|division}} operation in math. In this comic, [[Randall]] has used A as the dividend (the number being divided) and B as the divisor (the number that A is divided by). Division is the fourth simplest arithmetic operation in mathematics, after addition, subtraction, and multiplication.[https://plato.stanford.edu/entries/principia-mathematica/#PartIVRelaArit]

The first two of the seven notations shown are the {{w|division sign}} (÷) and the {{w|radix}} used for {{w|short division}} and {{w|long division}} in beginning arithmetic. (Note: the short/long division radix is only used in some countries, and there are [https://en.wikipedia.org/wiki/Long_division#Notation_in_non-English-speaking_countries different notations in the non-English speaking world]). These methods of division are often used by school children because the ÷ sign is what most people use when first learning division, and the short division radix is usually the first algorithm learned for dividing arbitrary dividends, typically starting with the easier abbreviated short division form.

The expression on the third line, A/B, is the way division is usually written in software code. The four simple arithmetic operations in programming usually are +, -, *, /. This one was missing in the first version of the comic. This is most commonly seen in regular mathematics as it somewhat saves space, and is easy to type with the slash key. Additionally, it uses standard {{w|ASCII}} characters instead of sophisticated notation.

The expression on the forth line, a/b, is how division is usually written when typography costs are not in question, in fraction notation. The Unicode character sets provide some specific fractions such as ⅓ as well as some superscript and subscript characters, so someone familiar with it might use it to write fractions such as ²²⁄₇. But this is tedious and can't be used on more complex expressions, so it is rarely used in everyday life (the fraction A/B cannot be written this way; there is a superscript A, but no subscript B).

The fifth notation is the way division is written in science: the dividend on the top of the expression over the divisor on the bottom under a horizontal line. This is how a {{w|Fraction|fraction}} would be written. It has the advantage of clearly separating the numerator and denominator when they are longer expressions, such as polynomials, without needing to add parentheses. This format is mostly used in written and professionally typeset math, as it can't be typed without something like {{w|MathML}}, {{w|LaTeX}} or HTML tables.

The sixth notation uses a negative exponent. The exponent -1 is equivalent to {{w|Multiplicative inverse|reciprocation}}. It can be used to keep the entire expression on one line. Note that ab-1 is equal to a/b. This format is often used to express physical units.

The final form of notation declares a function. The writer defines a new function, F, that takes in the parameters A and B, before listing out the function's definition (trailing off in increasingly smaller text). Randall warns the reader they should escape while they still can, because both the function itself and the math environment as a whole are going to get relatively tedious. Integer division can be defined in terms of multiplicative inequalities and the remainder, or modulo ('%' in Python), operator. This situation is likely to occur in abstract algebra, where one might have to define what "division" means for two elements of a mathematical object such as a group, ring, or magma. One example would be an object G, such that, for two elements A and B of G, "A divided by B" is defined as an element C such that CB=A, or alternatively as an element C such that BC=A. These definitions will differ if multiplication in G is not commutative. Furthermore, if such a C is not unique, the function F(A,B) will need to include a method to select a unique value for "A divided by B" for each A and B. Thus, the F(A,B) in the comic might not even refer to a uniquely defined operation, but simply to the property of a function F(A,B) that is a valid division operation on G, given some definition of division.

The title text recommends distinguishing ÷ from %.

==Transcript==
{{incomplete transcript|Do NOT delete this tag too soon.}}
:Division notation
:A÷B
:B⟌A Schoolchild.
:A/B Software engineer.
:A⁄B Normal person or Unicode enthusiast.
:A over B Scientist.
:AB-1 Fancy scientist.
:F(A, B) such that F(G)= (text getting smaller) Oh no, run

{{comic discussion}}

[[Category:Math]]
[[Category:Science]]
[[Category:Programming]]
[[Category:Science tip]]

2310: Great Attractor

2020-05-23T00:20:52Z

172.69.34.30: /* Explanation */ Beret guy's mom is probably not the cause of dark flow. It was just him misunderstanding a joke by cueball

{{comic
| number = 2310
| date = May 22, 2020
| title = Great Attractor
| image = great_attractor.png
| titletext = Living in the southern hemisphere was nice because I could jump extra high, but I like it here too. Besides, if I ever want to move back, I can just curl up in a ball and wait!
}}

==Explanation==
{{incomplete|Created by a Greatly Attractive SpaceBOT. Please mention here why this explanation isn't complete. Do NOT delete this tag too soon.}}

[[Cueball]] comments on the fact that as summer approaches, the sun rises earlier and sets later, a common topic of conversation, especially to complain that it is still light at times of day where you are used to it being dark out. [[Beret Guy]] comments that he fell off of the wall this morning, a seemingly unconnected topic. Cueball is understandably confused by this comment, so Beret Guy clarifies.

Beret Guy is strongly affected by the The {{w|Great Attractor}}, a large gravitational anomaly that influences the galaxies near it, but is difficult to observe directly. Beret Guy claims that the great attractor pulls on him unusually hard, which could be another one of his strange powers. This attraction, while not overpowering the gravity of the earth, (as he states that he can only "Jump extra high" in the Title Text) affects his life greatly, such as allowing him to sleep on walls. While 'normal' people can probably (if uncomfortably) lie down on the top of a boundary wall, for Beret Guy this may, at various times, mean that he can lie on the vertical surface of any wall (external or internal) that is currently orientated in a fortuitous direction.

He fell off of the Wall this morning due the Great Attractor being below him during daylight hours and on the horizon during night hours. Because the Day starts earlier in the summer, he fell unexpectedly.

He gives a short explanation of why The Great Attractor affects him, apparently caused by his bones existing in more dimensions than our normal 3 dimensions of space and 1 of time, and the motion of galaxies, which normally has no significant affect on a person.

Beret Guy then says that Day-Sliding Season is near, due to The Great Attractor being at the horizon in the Day, and offers to run errands for Cueball in the South, implying that he will be pulled towards the South During Day-Sliding Season.

Beret Guy is not standing straight up during this comic, he has one knee slightly bent; and walks with a strange gait and movement lines around him. This is presumably due to the extra downwards force that the Great Attractor is currently exerting on him, so he has to exert more effort to hold himself upright.

A prior example of an xkcd character with alternate gravitational susceptibility is [[417: The Man Who Fell Sideways]], where a consistent off-vertical pull somehow applies (rather than one linked to a spot on the skies) while other fictional examples of 'personalised' [https://wiki.lspace.org/mediawiki/Tethys gravitational] [https://wiki.lspace.org/mediawiki/Sally_Cambric susceptibilities] also exist, in various forms.
.

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

:[Cueball and Beret Guy stand next to each other, talking.]
:Cueball: I can't believe it's still light out. It's 8:00 PM!
:Beret Guy: Seriously! This morning I fell off the wall.

:[In a frameless panel, Cueball and Beret Guy are still standing and talking. Beret Guy is gesturing to the right.]
:Cueball: Wait, why were you sleeping on the wall?
:Beret Guy: The Great Attractor is near the horizon at night right now.

:[A regular panel, zoomed in on Beret Guy, who is gesturing to the left.]
:Cueball (off screen): The Great Attractor?
:Beret Guy: Yeah! The space one.
:Beret Guy: It pulls on me extra hard. Doctors said it's something to do with galactic motion and how many dimensions my bones have.

:[Zoomed back out to show Cueball, standing still, and Beret Guy, who is sliding away to the right.]
:Beret Guy: This time of year, it's below us all day, so I stand vertically. But day-sliding season is near!
:Beret Guy: Let me know if you have any errands to run to the south!
:Beret Guy: ''Goodniiighttt''

{{comic discussion}}
[[Category: Comics featuring Cueball]]
[[Category: Comics featuring Beret Guy]]

Category:COVID-19

2020-03-31T21:28:38Z

172.69.34.30: subcategory?

*These comics are inspired by the {{w|2019–20 coronavirus pandemic|2019-20 pandemic}} of the {{w|coronavirus}} {{w|SARS-CoV-2}} which results in the {{w|Coronavirus disease 2019}}, COVID-19 for short.
*[[Randall]] has made twelve comics in a row so far alluding to the outbreak.
**The fifth of these, [[2279: Symptoms]], came out on March 11, 2020, the day when the outbreak was declared a world wide {{w|pandemic}}.

[[Category:Comics by topic]]
[[Category:Biology]]

2287: Pathogen Resistance

2020-03-31T21:28:16Z

172.69.34.30: /* Trivia */ biology

{{comic
| number = 2287
| date = March 30, 2020
| title = Pathogen Resistance
| image = pathogen_resistance.png
| titletext = We're not trapped in here with the coronavirus. The coronavirus is trapped in here with us.
}}

==Explanation==
{{incomplete|Created by a WORRIED BACTERIOPHAGE. Please mention here why this explanation isn't complete. Do NOT delete this tag too soon.}}
This comic is the 13th comic in a row in a [[:Category:COVID-19|series of comics]] about the {{w|2019–20 coronavirus outbreak|2020 pandemic}} of the {{w|coronavirus}} - {{w|SARS-CoV-2}}.

Rather than expressing humanity's fears and pessimism about the pandemic, this strip anthropomorphizes some of the pathogens which afflict humanity and presents ''their'' fears and pessimism about possibly going extinct. This serves as a roundabout way of expressing hope and wonder at the ingenuity and tenacity of humans in the face of diseases past (with water sanitation, mosquito netting, and condoms) and present (with the power of social distancing and {{w|Gloria Gaynor}}'s hit song ''{{w|I Will Survive}}''). Gaynor recorded [https://www.cnn.com/2020/03/12/entertainment/coronavirus-gloria-gaynor-i-will-survive-trnd/index.html a video of herself washing her hands] for 20 seconds (the recommended length of time to wash hands for optimal cleanliness) to the background of her hit song.

The three pathogens presented are a {{w|bacteriophage}}, a small colony of a {{w|coccus}}-shaped bacterium (such as ''{{w|Streptococcus}}''), and a {{w|protozoon}} (a caricature of a {{w|ciliate}}). Bacteriophages do not infect human cells (as the name suggests, they only infect bacteria), and have been studied for use as "{{w|phage therapy}}" ''for'' humans, especially in dealing with antibiotic-resistant bacterial infections (which is usually what people mean when they talk about "resistance" in the context of pathogens), but they are iconic, instantly-recognizable viruses, and some have been found to [https://phys.org/news/2015-11-bacteria-bacteriophages-collude-formation-clinically.html collude with bacteria] in forming certain antibiotic-resistant {{w|biofilm}}s.

The comic humorously considers pasta as an essential part of humans' fight against coronavirus. Pasta is an example of a dried food that can last a long time, if the orders to stay indoors continue. However, not every culture consumes or likes pasta.

The colony of cocci protests that it shouldn't be possible for humans to evolve "pathogen resistance" in the short period of months since the breakout of COVID-19, when humans require over a decade to reach sexual maturity, and in modern times often wait at least two decades before having children. Bacteria and viruses, on the other hand, reproduce in a matter of minutes, so that there may be hundreds of generations per day (comparable to the number of generations that have passed for humanity since the beginnings of agriculture), each of which presents opportunities to evolve new antigens that are not recognized by any antibodies present in the body or to evolve resistance to whatever antibiotic drugs a human might be using. However, as the bacteriophage explains, humans generally do not become resistant against pathogens by genetic drift (although there are researchers who are seeking to identify genes that encode resistances to various diseases and then propagate them to other humans through gene editing, as in the {{w|He Jiankui affair}}). Instead, humans "evolve" pathogen resistance through behavioral changes. The behaviors presented in this comic strip include:

* Municipal water supplies, which are filtered and treated to prevent the spread of waterborne diseases, like cholera and dysentery.
* Mosquito netting over beds, and also anti-insect poisoning, to prevent the spread of vector-borne diseases, like malaria.
* Condoms, to prevent the spread of sexually-transmitted diseases, such as AIDS and syphilis.
* Social or physical distancing, hand-washing, storable food, and electronic communications, to prevent the spread of diseases through casual contact, like COVID-19.

These behaviors do not come from our genomes, passed along through reproduction, but from our brains, passed along by communication. Some of the language of epidemiology is also used in discussion of communication, most notably "going viral" -- in this case, information is going viral to prevent viruses from going viral.

The title text reverts to the point of view of humans and references a famous line from the graphic novel ''{{w|Watchmen}}'', where {{w|Rorschach (character)|Rorschach}}, whilst in prison and surrounded by enemies who want to kill him, proclaims: "I'm not locked up in here with YOU. You're locked up in here with ME." This presents an alternate perspective on quarantine and isolation that some may find more bearable: rather than passively hiding indoors in fear of the virus, we are taking action to fragment the virus population so that our immune systems (and medical intervention, in more serious cases) can {{w|defeat in detail|defeat it in detail}}.

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

:[A small colony of coccus bacteria, a bacteriophage, and a protozoon are floating together.]
:Bacteriophage: I'm worried about humans developing resistance to us.
:Bacteriophage: Using pasta.

:[Cutaway to macrophages and antibodies chasing three protozoa. One protozoon is already covered in antibodies.]
:Bacteriophage (narrating): The human immune system is a nightmare.
:Bacteriophage (narrating): It's the worst.
:Bacteriophage (narrating): It's the scariest thing in the universe.
:Macrophage: ''Who wants a [https://www.sciencedaily.com/releases/2017/03/170307142718.htm HUUGGG]''
:Antibody-covered protozoon: ''Nooo!''

:[Close-up on bacteriophage]
:Bacteriophage: We can only survive by staying ahead of it. Keep jumping from person to person, keep mutating and evolving.
:Bacteriophage: But now humans are adapting too fast.

:[Water pipes. A mosquito net with a bed under it. An unopened condom package.]
:Bacteriophage (narrating): We spread through their water. They built pipes.
:Bacteriophage (narrating): We used mosquitoes. They put out nets and poison everywhere.
:Bacteriophage (narrating): We spread through sex, and suddenly they all had these plastic things.

:[Depictions of coronavirus with spikes. Hairbun and Cueball shaking hands, with droplets spraying from both their mouths.]
:Bacteriophage (narrating): This time, we really thought we had them.
:Bacteriophage (narrating): One of us got good at transmission through everyday contact.

:[A row of 4 sets of human lungs, the first with several black dots, the second and third with increasing black parts, the fourth completely filled with black. A graph showing exponential growth.]
:Bacteriophage (narrating): It was great. We were tearing through lungs, spreading like wildfire.
:Voice offscreen: Hooray!
:Voice 2 offscreen: I ''hate'' lungs.

:[Close-up of bacteriophage "head".]
:Bacteriophage: Then, all of a sudden, humans everywhere just...''stopped''. They stopped working, stopped seeing friends.

:[Megan is sitting on a couch, watching a flat screen. Cueball is at a sink with a mirror, washing his hands. They are facing away from each other.]
:Voice offscreen: What are they ''doing''?
:Voice 2 offscreen: Nothing!
:Voice 2 offscreen: They're just sitting there in their houses washing their hands.

:[A single human in a empty room, surrounded by fallen droplets. Among the droplets is a coronavirus.]
:Bacteriophage (narrating): Suddenly humans became dead ends. We tried to jump from one to the next, but there's no one to jump to.
:Bacteriophage (narrating): We can't escape.
:Coronavirus: Help!

:[Coronaviruses, encroached on by macrophages and streams of antibodies.]
:Bacteriophage (narrating): We're trapped in there with those ghastly immune systems.
:Antibodies: ''IT'S HUUG TIIIIIME''
:Macrophage: Come here for a HUUUG
:Macrophage: HUUUUGS

:[Coronaviruses covered in antibodies and surrounded by macrophages. Some of the macrophages are devouring viruses. Others contain broken-down remnants.]
:Bacteriophage (narrating): Even if we win a fight, there's nowhere to go.
:Macrophage: HUUUUUUUGGSS
:Macrophage: HUUUUGS
:Bacteriophage (narrating): By staying inside, humans have become resistant.

:[Back to the discussion between the coccus, the bacteriophage and the protozoan.]
:Coccus bacteria: How could they evolve that fast? Humans take decades to reproduce!
:Bacteriophage: It's not evolution. It's something with their brains.
:Protozoon: I ''wondered'' what those were for!

:[Bacteriophage pointing to: Cueball and Megan looking at their phones; Megan and Cueball walking to the right; Megan and Cueball at separate sinks washing their hands.]
:Bacteriophage: Humans started looking at their phones, talking, writing words, and making signs. A human named "Gloria Gaynor" filmed herself singing at her bathroom sink.
:Bacteriophage: And then they bought lots of pasta.
:Bacteriophage: Then, around the world, they all went home and started washing their hands.

:[Bacteriophage and protozoan.]
:Bacteriophage: They saw what we were doing and changed their behavior to stop us.
:Protozoon: Brains are the ''worst''.

:[Coccus, bacteriophage and protozoan.]
:Coccus bacteria: It's not over, right? They can't sustain this. They must be bored and tired.
:Coccus bacteria: Will they give up?
:Bacteriophage: I don't know. They seem determined to protect each other.

:[Coccus, bacteriophage and protozoan.]
:Bacteriophage: And
:Bacteriophage: They have a ''lot'' of pasta.

==Trivia==
* The title text originally contained a typo in the form of a double negative "We're not not trapped..." This has since been corrected.

{{comic discussion}}

[[Category:COVID-19]]
[[Category:Biology]]
[[Category:Comics featuring Cueball]]
[[Category:Comics featuring Megan]]
[[Category:Comics featuring Hairbun]]
[[Category:Comics featuring real people]]

2287: Pathogen Resistance

2020-03-31T21:23:34Z

172.69.34.30: /* Explanation */ wiki direct links

{{comic
| number = 2287
| date = March 30, 2020
| title = Pathogen Resistance
| image = pathogen_resistance.png
| titletext = We're not trapped in here with the coronavirus. The coronavirus is trapped in here with us.
}}

==Explanation==
{{incomplete|Created by a WORRIED BACTERIOPHAGE. Please mention here why this explanation isn't complete. Do NOT delete this tag too soon.}}
This comic is the 13th comic in a row in a [[:Category:COVID-19|series of comics]] about the {{w|2019–20 coronavirus outbreak|2020 pandemic}} of the {{w|coronavirus}} - {{w|SARS-CoV-2}}.

Rather than expressing humanity's fears and pessimism about the pandemic, this strip anthropomorphizes some of the pathogens which afflict humanity and presents ''their'' fears and pessimism about possibly going extinct. This serves as a roundabout way of expressing hope and wonder at the ingenuity and tenacity of humans in the face of diseases past (with water sanitation, mosquito netting, and condoms) and present (with the power of social distancing and {{w|Gloria Gaynor}}'s hit song ''{{w|I Will Survive}}''). Gaynor recorded [https://www.cnn.com/2020/03/12/entertainment/coronavirus-gloria-gaynor-i-will-survive-trnd/index.html a video of herself washing her hands] for 20 seconds (the recommended length of time to wash hands for optimal cleanliness) to the background of her hit song.

The three pathogens presented are a {{w|bacteriophage}}, a small colony of a {{w|coccus}}-shaped bacterium (such as ''{{w|Streptococcus}}''), and a {{w|protozoon}} (a caricature of a {{w|ciliate}}). Bacteriophages do not infect human cells (as the name suggests, they only infect bacteria), and have been studied for use as "{{w|phage therapy}}" ''for'' humans, especially in dealing with antibiotic-resistant bacterial infections (which is usually what people mean when they talk about "resistance" in the context of pathogens), but they are iconic, instantly-recognizable viruses, and some have been found to [https://phys.org/news/2015-11-bacteria-bacteriophages-collude-formation-clinically.html collude with bacteria] in forming certain antibiotic-resistant {{w|biofilm}}s.

The comic humorously considers pasta as an essential part of humans' fight against coronavirus. Pasta is an example of a dried food that can last a long time, if the orders to stay indoors continue. However, not every culture consumes or likes pasta.

The colony of cocci protests that it shouldn't be possible for humans to evolve "pathogen resistance" in the short period of months since the breakout of COVID-19, when humans require over a decade to reach sexual maturity, and in modern times often wait at least two decades before having children. Bacteria and viruses, on the other hand, reproduce in a matter of minutes, so that there may be hundreds of generations per day (comparable to the number of generations that have passed for humanity since the beginnings of agriculture), each of which presents opportunities to evolve new antigens that are not recognized by any antibodies present in the body or to evolve resistance to whatever antibiotic drugs a human might be using. However, as the bacteriophage explains, humans generally do not become resistant against pathogens by genetic drift (although there are researchers who are seeking to identify genes that encode resistances to various diseases and then propagate them to other humans through gene editing, as in the {{w|He Jiankui affair}}). Instead, humans "evolve" pathogen resistance through behavioral changes. The behaviors presented in this comic strip include:

* Municipal water supplies, which are filtered and treated to prevent the spread of waterborne diseases, like cholera and dysentery.
* Mosquito netting over beds, and also anti-insect poisoning, to prevent the spread of vector-borne diseases, like malaria.
* Condoms, to prevent the spread of sexually-transmitted diseases, such as AIDS and syphilis.
* Social or physical distancing, hand-washing, storable food, and electronic communications, to prevent the spread of diseases through casual contact, like COVID-19.

These behaviors do not come from our genomes, passed along through reproduction, but from our brains, passed along by communication. Some of the language of epidemiology is also used in discussion of communication, most notably "going viral" -- in this case, information is going viral to prevent viruses from going viral.

The title text reverts to the point of view of humans and references a famous line from the graphic novel ''{{w|Watchmen}}'', where {{w|Rorschach (character)|Rorschach}}, whilst in prison and surrounded by enemies who want to kill him, proclaims: "I'm not locked up in here with YOU. You're locked up in here with ME." This presents an alternate perspective on quarantine and isolation that some may find more bearable: rather than passively hiding indoors in fear of the virus, we are taking action to fragment the virus population so that our immune systems (and medical intervention, in more serious cases) can {{w|defeat in detail|defeat it in detail}}.

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

:[A small colony of coccus bacteria, a bacteriophage, and a protozoon are floating together.]
:Bacteriophage: I'm worried about humans developing resistance to us.
:Bacteriophage: Using pasta.

:[Cutaway to macrophages and antibodies chasing three protozoa. One protozoon is already covered in antibodies.]
:Bacteriophage (narrating): The human immune system is a nightmare.
:Bacteriophage (narrating): It's the worst.
:Bacteriophage (narrating): It's the scariest thing in the universe.
:Macrophage: ''Who wants a [https://www.sciencedaily.com/releases/2017/03/170307142718.htm HUUGGG]''
:Antibody-covered protozoon: ''Nooo!''

:[Close-up on bacteriophage]
:Bacteriophage: We can only survive by staying ahead of it. Keep jumping from person to person, keep mutating and evolving.
:Bacteriophage: But now humans are adapting too fast.

:[Water pipes. A mosquito net with a bed under it. An unopened condom package.]
:Bacteriophage (narrating): We spread through their water. They built pipes.
:Bacteriophage (narrating): We used mosquitoes. They put out nets and poison everywhere.
:Bacteriophage (narrating): We spread through sex, and suddenly they all had these plastic things.

:[Depictions of coronavirus with spikes. Hairbun and Cueball shaking hands, with droplets spraying from both their mouths.]
:Bacteriophage (narrating): This time, we really thought we had them.
:Bacteriophage (narrating): One of us got good at transmission through everyday contact.

:[A row of 4 sets of human lungs, the first with several black dots, the second and third with increasing black parts, the fourth completely filled with black. A graph showing exponential growth.]
:Bacteriophage (narrating): It was great. We were tearing through lungs, spreading like wildfire.
:Voice offscreen: Hooray!
:Voice 2 offscreen: I ''hate'' lungs.

:[Close-up of bacteriophage "head".]
:Bacteriophage: Then, all of a sudden, humans everywhere just...''stopped''. They stopped working, stopped seeing friends.

:[Megan is sitting on a couch, watching a flat screen. Cueball is at a sink with a mirror, washing his hands. They are facing away from each other.]
:Voice offscreen: What are they ''doing''?
:Voice 2 offscreen: Nothing!
:Voice 2 offscreen: They're just sitting there in their houses washing their hands.

:[A single human in a empty room, surrounded by fallen droplets. Among the droplets is a coronavirus.]
:Bacteriophage (narrating): Suddenly humans became dead ends. We tried to jump from one to the next, but there's no one to jump to.
:Bacteriophage (narrating): We can't escape.
:Coronavirus: Help!

:[Coronaviruses, encroached on by macrophages and streams of antibodies.]
:Bacteriophage (narrating): We're trapped in there with those ghastly immune systems.
:Antibodies: ''IT'S HUUG TIIIIIME''
:Macrophage: Come here for a HUUUG
:Macrophage: HUUUUGS

:[Coronaviruses covered in antibodies and surrounded by macrophages. Some of the macrophages are devouring viruses. Others contain broken-down remnants.]
:Bacteriophage (narrating): Even if we win a fight, there's nowhere to go.
:Macrophage: HUUUUUUUGGSS
:Macrophage: HUUUUGS
:Bacteriophage (narrating): By staying inside, humans have become resistant.

:[Back to the discussion between the coccus, the bacteriophage and the protozoan.]
:Coccus bacteria: How could they evolve that fast? Humans take decades to reproduce!
:Bacteriophage: It's not evolution. It's something with their brains.
:Protozoon: I ''wondered'' what those were for!

:[Bacteriophage pointing to: Cueball and Megan looking at their phones; Megan and Cueball walking to the right; Megan and Cueball at separate sinks washing their hands.]
:Bacteriophage: Humans started looking at their phones, talking, writing words, and making signs. A human named "Gloria Gaynor" filmed herself singing at her bathroom sink.
:Bacteriophage: And then they bought lots of pasta.
:Bacteriophage: Then, around the world, they all went home and started washing their hands.

:[Bacteriophage and protozoan.]
:Bacteriophage: They saw what we were doing and changed their behavior to stop us.
:Protozoon: Brains are the ''worst''.

:[Coccus, bacteriophage and protozoan.]
:Coccus bacteria: It's not over, right? They can't sustain this. They must be bored and tired.
:Coccus bacteria: Will they give up?
:Bacteriophage: I don't know. They seem determined to protect each other.

:[Coccus, bacteriophage and protozoan.]
:Bacteriophage: And
:Bacteriophage: They have a ''lot'' of pasta.

==Trivia==
* The title text originally contained a typo in the form of a double negative "We're not not trapped..." This has since been corrected.

{{comic discussion}}

[[Category:COVID-19]]
[[Category:Comics featuring Cueball]]
[[Category:Comics featuring Megan]]
[[Category:Comics featuring Hairbun]]
[[Category:Comics featuring real people]]

2286: 6-Foot Zone

2020-03-30T21:29:11Z

172.69.34.30:

{{comic
| number = 2286
| date = March 27, 2020
| title = 6-Foot Zone
| image = 6_foot_zone.png
| titletext = Technically now it's a 34-foot zone.
}}

==Explanation==
{{incomplete|Created by the 8 social-distancing horses, who are not themselves socially distancing. Please mention here why this explanation isn't complete. Do NOT delete this tag too soon.}}
This comic is the 11th comic of the last 12 ([[2283: Exa-Exabyte]] was unrelated) in a [[:Category:COVID-19|series of comics]] related to the {{w|2019–20 coronavirus pandemic|2020 pandemic}} of the {{w|coronavirus}} - {{w|SARS-CoV-2}}.

This comic is about {{w|social distancing}}, a common practice to prevent the spread of the COVID-19 disease. It has been suggested to maintain 6 feet (i.e. 1.83 m - in e.g. France and Britain the suggested distance is 2 m) of distance between yourself and other people, to prevent the transmission of respiratory droplets from you to others (or vice versa).

[[Randall]] takes this 6 feet of distance, and does calculations of the "area" of distancing, "border", population density, and "real estate value". He finally culminates in determining the number of horses that could also fit in the space.

Randall's border length and approximate area calculations are based on a zone with an outside radius of approximately 6.8 feet or 82 inches (2.07 m), meaning that the person has a radius of approximately 0.8 feet (9.6 in, 0.24 m). That is, 2π(6.8ft) = 42.7 ft and π(6.8ft)2 = 145.3 ft2.

There are two different population densities that can be calculated. The one used by Randall in the comic is the population density of the exclusion zone itself, i.e. just the reciprocal of its area. This is π-1(6.8 ft)-2 = 190,000 mi-2. A different density is the density of a crowd in which everyone obeys the distancing rules. That would result in 0.9069(π-1)(3.8ft)-2 = 560,000 mi-2 population density. When people stand 6ft apart from each other, their exclusion zones are overlapping; instead we can use smaller circles with 3.8 ft radius that are not overlapping. 0.9069 is the packing density of circles in the plane.
For comparison, only 21 countries have a population density >1000 mi-2, but there are {{w|List_of_cities_proper_by_population_density|a few cities}} with a population density on the same order of magnitude (~100,000 mi-2).

The ''[https://www.fs.fed.us/t-d/pubs/htmlpubs/htm07232816/toc.htm USFS Equestrian Design Guidebook]'' is (of course) a real thing, and it discusses the [https://www.fs.fed.us/t-d/pubs/htmlpubs/htm07232816/page03.htm#phys dimensions of the design horse]

The title text is a pun using the alternate definition of foot by switching the naming from 6-foot zone, where foot is used as a unit of distance, to 34-foot zone, where the number represents the total number of feet inside the circle, including the horses’ feet.

==Transcript==
{{incomplete transcript|Do NOT delete this tag too soon.}}
:Guide to the 6' Social Distancing Zone
:[Profile image of Megan with 6 foot distance measurements on both sides.]
:[Overhead image of a person within a roughly circular shape extending 6 feet in all directions from the person. The dimensions of the person account for the non-circular shape.]
:Approx. area: 145 ft2
:Border length: 43 ft
:Population density: 190,000 people/mile2
:Value at NYC real estate price/ft2: $195,000
:Maximum number of horses that could fit inside it with you, estimated using the dimensions in the ''US Forest Service Equestrian Design Handbook'': 8
{{comic discussion}}

[[Category:COVID-19]]
[[Category:Comics featuring Megan]]
[[Category:Comics featuring Cueball]]
[[Category:Animals]]