explain xkcd - User contributions [en]

978: Citogenesis

2022-06-26T17:58:40Z

108.162.221.239:

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Talk:2275: Coronavirus Name

2020-03-03T03:55:42Z

108.162.221.239:

Covid-19 is more dangerous than the flu and has already killed more people. And any death rate that starts with 0.00 and then has a number other than zero can only be called "basically zero" if you value human life very little. [[Special:Contributions/162.158.94.132|162.158.94.132]] 21:49, 2 March 2020 (UTC)
:addendum: this seems to depend on what source you use for the chinese yearly flu death rate. number of deaths is either much higher or somewhat lower.[[Special:Contributions/162.158.91.123|162.158.91.123]] 21:53, 2 March 2020 (UTC)
:It's Trump taking point that the coronavirus is a hoax and no worse than the flu. [[Special:Contributions/162.158.74.213|162.158.74.213]] 22:14, 2 March 2020 (UTC)
:At the very least, the fact the virus has over 90,000 confirmed cases makes it a significant disease. [[Special:Contributions/172.69.34.246|172.69.34.246]] 22:28, 2 March 2020 (UTC)
:It doesn't seem like the point of the comic is to comment on the severity of the virus. Seems more on-topic to say things that are objectively true, like "Many people are concerned about the virus" rather than discussing disputed stats.[[Special:Contributions/162.158.106.132|162.158.106.132]] 22:58, 2 March 2020 (UTC) Patb

If the Godzilla movies have taught me anything, it's that giant insects aren't a problem biologists can solve anyways. That's more of a "nuclear paleontology" sort of job. [[User:GreatWyrmGold|GreatWyrmGold]] ([[User talk:GreatWyrmGold|talk]]) 01:43, 3 March 2020 (UTC)

It is legitimately difficult to tell if Ponytail's use of the word 'catchy' as a descriptor for 'coronavirus' is an intentional or unintentional pun. Either way, it's very opportune. [[Special:Contributions/108.162.221.239|108.162.221.239]] 03:55, 3 March 2020 (UTC)

2242: Ground vs Air

2019-12-17T16:22:47Z

108.162.221.239: Geologically accurate note on "fire"

{{comic
| number = 2242
| date = December 16, 2019
| title = Ground vs Air
| image = ground vs air.png
| titletext = Water is thinner than both, and fire is *definitely* thicker.
}}

==Explanation==
{{incomplete|Created by a THICK FIRE. More on the general thickness of the "ground", especially on the oceans and at the thickest parts. Needs more about the actual data portrayed.}}
This comic depicts a map of the world, using the {{w|Winkel tripel projection}}, comparing the thickness of the ground, which refers to the {{w|lithosphere}}, to the thickness of the air above it, which refers to the {{w|atmosphere}}.

In an inserted figure, Randall defines the thickness using three boundaries. At the top is {{w|space}}, defined by the {{w|Kármán line}} at an altitude of 100 km (≈ 62 mi). Below that is the atmosphere which goes down to the ground, where [[Cueball]] is standing, including the ocean down to the seafloor as indicated on the left side. Beneath the surface is the lithosphere, comprised of the Earth's crust along with the rigid upper part of the mantle, and beneath this is the {{w|Asthenosphere}}, the partially melted, highly viscous region of the {{w|upper mantle}} just below the lithosphere. The lithosphere is variable in thickness, averaging about 100 km, but the oceanic lithosphere is much thinner than the continental lithosphere (oceanic crust is thinner and denser than continental crust). The two measurements are between space and the surface, and the surface to the asthenosphere.

The map shades in the parts where the second measurement is thicker than the first. This almost only occurs over continents, and certainly only where the continental plates are located (which can stretch into the shallow parts of the oceans). But there are several sections, such as in the Caribbean and the Sea of Japan, where the ground is thicker even being below sea level.

Randall has mainly used a work by Conrad and Lithgow-Bertelloni from 2006 to estimate the thickness of the "ground", and he gives the reference to the paper [https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2005GL025621 DOI.1029/2005GL025621]. Basically, Randall has taken their map and shaded the blue areas. It is the second comic in a row with a citation, after the footnote in [[2241: Brussels Sprouts Mandela Effect]].

[[Randall]] always uses the Kármán line as the boundary between Earth's atmosphere and space. He has previously mocked the alternative definition of the atmosphere boundary (at 80 km ≈ 50 mi) used by US Air Force and NASA in the title text [[1375: Astronaut Vandalism]]. That definition would, of course, have resulted in a significantly different picture where the ''air'' is thicker than the ''ground'' only inside small areas around mid-ocean ridges.

The title text referrers to the ancient four {{w|classical element}}s earth, water, air, fire. The lithosphere, or ground, is earth, the oceans is water, the atmosphere is air, and fire would thus be the hot, plastic rock of the Earth's mantle. (Randall is likely referring to how the mantle is frequently represented in drawings as fiery red molten rock, even though the mantle is solid--none of it is magma or otherwise "on fire" except in small volumes at locations very close to the crust.) See [[913: Core]]. The water layer on Earth is never more than 11 km deep at the {{w|Mariana Trench}}, and thus cannot compare to the thickness of the atmosphere or the lithosphere. An expansive definition of "fire" to include the rest of the Earth below the lithosphere puts the fire layer at 6000 km thick, much thicker than the other layers.

In [[977: Map Projections]] the [[977:_Map_Projections#Winkel-Tripel|Winkel-Tripel projection]] is the fifth projection which is linked to the {{w|Hipster (contemporary subculture)|hipster}} subculture.

==Transcript==
:[Caption above the drawing]:
:Which is thicker—the ground or the air?

:[The drawing shows a Winkel tripel projection of the Earth. The features of the main map is unlabeled, with only the outlines of the landmasses present. Various parts of the map are labeled with "Air" (four times) or "Ground (5 times)." Areas marked as "Ground" are differentiated with gray shading. These are always over large landmasses or close to them. They cover most of North America (labeled), the northern part of South America (labeled), Northern Europe and most of Asia (labeled), Japan, Most of Australia and part of sea above, Western Africa, the part of Africa beneath Equator (labeled), and finally the central parts of Antarctica (labeled). Air is written on the East coast of America, in the Atlantic Ocean, over the central part of Africa and in the Pacific Ocean east of China.]
:[Over East coast of America]: Air
:[Over North America]: Ground
:[Over Atlantic Ocean]: Air
:[Over South America]: Ground
:[Over central part of Africa]: Air
:[Over south part of Africa]: Ground
:[Over Asia]: Ground
:[Over Pacific Ocean]: Air
:[Over Antarctica ]: Ground

:[A small diagram is present in the Pacific Ocean left of South America. The diagram depicts several labeled layers of Earth and its atmosphere, listed below. Cueball, a body of water, and several mountains are shown on the flat surface part of the diagram, with the ocean floor lower than where Cueball stand. Above is a line representing the border to space. The line beneath the surface is much more curved going both up and down. Two double arrows representing the thickness of the atmosphere and the Lithosphere are drawn between the surface and the layers above and below. Another curved double arrow is pointing to each of these distances and it is marked with a question mark in the middle of the line.]
:Space
:Atmosphere
:Lithosphere
:Asthenosphere
:?

:[In the bottom right corner of the comic with gray text is a reference:]
:Based mostly on Conrad and Lithgow-Bertelloni (2006) DOI.1029/2005GL025621

{{comic discussion}}


[[Category: Comics featuring Cueball]]
[[Category:Maps]]
[[Category:Geology]]
[[Category:Space]]

1159: Countdown

2019-12-06T17:55:09Z

108.162.221.239: fixed typo

{{comic
| number = 1159
| date = January 11, 2013
| title = Countdown
| image = countdown.png
| titletext = For all we know, the odds are in our favor.
}}

==Explanation==
The comic shows a {{w|seven segment display}} (aka [http://www.ece.mtu.edu/labs/EElabs/EE2304/pages/bcd_to_seven_segment_TAversion.html calculator-style numbers]) with a countdown. [[Black Hat]] explains that it is a countdown, maybe to a {{w|supervolcano}} eruption. However, an unfortunately placed picture blocks view of the full display. Due to the form of a seven-segment display, the first digit could be 0, 6, or 8, and five digits are completely blocked by the picture. [[Cueball]] is worried and asks him to move the picture, but Black Hat lazily or teasingly refuses to move it.

He has already teased that he doesn't know what the countdown is for. His reply can either be understood as if he does not know which one of the ({{w|Supervolcano#VEI_8|seven potential}}) supervolcanos it is counting down to, or to which other {{w|Global catastrophic risk|cataclysmic event}} it is a countdown for (such as a {{w|Impact event|meteor strike}} or global {{w|Nuclear warfare|nuclear war}} for instance - it could also just be a general {{w|Doomsday Clock}}). Since it seems to be Black Hat's countdown, it is safe to assume that he knows both what it counts down to and when it stops, but he just likes to mess with peoples' minds.

The fully visible part starts at 2409, and based on the pace of the scene, it seems to be in seconds. Thus, it is unclear when the eruption might occur. If the obscured digits are all 0s, it could be as soon as 40 minutes. On the other hand, if the obscured digits are '899 999', there's another 2.85 million years to go; if they are '000 001', we have a little more than 3 years.

The choice of the picture is probably also interesting. The image is distorted enough that you can imagine it as being two very different images.
#It could depict a setting sun either reflecting in an ocean or with a river (possible also a lake) running out of the picture. But if it is a sun it is not very circular, although there do appear lines to indicate it is shining. This could maybe be explained with atmospheric interference.
#Alternatively it depicts an exploding volcano, a mountain with lines away from it to indicate the explosion or the eruption. And then it is lava flowing away from it or collecting in lakes.
In either case it makes sense, so maybe this is on purpose. If it is a volcano, the supervolcano clock makes sense. On the other hand, we are talking about the possible end of the world as we know it, and for this kind of theme a sun setting upon humanity would be a great metaphor.

The title text: "For all we know, the odds are in our favor" could imply the assumption that since we can't see the digits behind the picture, we can treat them as random. If so, chances are only 1 in 300 000 they are all zeros. However, because of statistical principles such as {{w|Benford's law}}, the digits are not entirely random, and the {{w|odds}} are higher than 1/299 999 for all the digits to be zero, since the middle 4 digits are zero.

In an alternative view, the strip is not about pondering at distributions of digits on an oracle countdown. It's more of a grim view of our natural disasters prediction capabilities. As they say – the question is not if it will happen but when it will happen. "Move the picture" would mean investing into research and warning systems - that would correspond to shifting the picture to the left. If we disregard the 40 minutes, but instead think of it as arbitrary interval of interests, minuscule as we folks have them, say - one's lifetime; or grimmer yet - some {{w|term of office}}. Because, hey, year after year passes and no apocalypse has been observed - the empirical odds are low indeed. An interesting question is what we would use the knowledge of the timing of our impending doom, if it is an event we can do nothing about, such as stopping a supervolcanic eruption or a large asteroid with direct impact course on Earth. Would we not have lives more happily for our remaining years, how few that might be, while not knowing... On the other hand, if the event is something we might prevent given enough time to plan (and the funding resources such knowledge would ensure), then it may have saved us, if we moved the picture just in time!

Using a countdown theme for comic #1159 could be a subtle joke, as 11:59/23:59 is one minute to midnight (on the Doomsday clock!)

Supervolcanos were also referenced in the title text of [[1053: Ten Thousand]] and it is the subject of in [[1611: Baking Soda and Vinegar]].

==Transcript==
:[Black Hat is sitting with his laptop on a desk when Cueball, standing behind him, looks up on the wall and asks him about the large digital countdown timer with red numbers which is hanging high up on the wall. It has a white frame around the black display with the red numbers. Most of the left part of the counter is covered by a framed picture which hangs on a string attached to a nail above the counter. The picture depicts either a setting sun reflecting in an ocean, or an exploding volcano with lava flowing away from it. The picture does not block the left most part of the frame around the counter, and it is also possible to see the two left-most lines of the first digit on the countdown, so they are both turned on. This proves that the numbers goes all the way to the left end. The next five digits are covered by the picture. Then one digit is only partly covered, as only the two most left lines are not visible. From the visible lines it is though clear that this digit shows a 0. The next seven digits are fully visible, giving eight discernible digits.]
:
:'''00002409'''
:
:Cueball: What's that?
:Black Hat: Countdown.
:[Same picture, but Cueball is looking at Black Hat. The counter counts down.]
:
:'''00002400'''
:
:Cueball: To what?
:Black Hat: Supervolcano, I think. I forget which one.
:[Cueball looks up again for about 18s (between 2nd and fourth image) - beat panel.]
:
:'''00002396'''
:
:[Cueball looks at Black Hat again.]
:
:'''00002382'''
:
:Cueball: Maybe we should move that picture?
:Black Hat: Too hard to reach. It's probably fine.

{{comic discussion}}

[[Category:Comics with color]]
[[Category:Comics featuring Cueball]]
[[Category:Comics featuring Black Hat]]
[[Category:Math]]
[[Category:Statistics]]
[[Category:Time]]

2231: The Time Before and After Land

2019-11-21T14:31:11Z

108.162.221.239: /* Explanation of time ranges on the chart */ the first bees appeared about 130 million years ago, 50 million years before the first known fossil bee, and probably very shortly after the first flowers evolved in the Cretaceous.

{{comic
| number = 2231
| date = November 20, 2019
| title = the Time Before And After Land
| image = the_time_before_and_after_land.png
| titletext = According to Google, "the time for Beeland" is apparently whenever you're looking for delicious honey in Spillimacheen, British Columbia or a hexagonal chalet in the Savinja valley in Slovenia.
}}

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

This comic is wordplay on ''{{w|The Land Before Time (franchise)|The Land Before Time}}'', a film series centered on dinosaurs.

This comic shows a timeline of the history of the universe, from the {{w|Big Bang}} to the present day. Various permutations of "Land Before Time" are highlighted on the timeline - for example, the "time before land" is the period of time before any land existed in the universe. (If only land on Earth was counted, then the time before land would have extended until [https://curiosity.com/topics/the-first-continent-on-earth-curiosity/ 3 billion years BC]; Earth existed before then, but the oceans covered its entire surface.)

Some of the wordplay arises from exchanging the {{w|homophonous}} words "time" and “thyme", and the {{w|homonyms}} “land” meaning ground, and “land “ meaning to go from sky to ground, creating even more permutations. Additional words like "the", "on", etc. are sometimes added.

The timeline includes points of interest to help understand the highlighted periods.

===Explanation of time ranges on the chart===

{| class="wikitable"
! Range !! From !! To !! Explanation
|-
|width=15%|'''The time before land'''
|width=10%|Big Bang
|width=10%|Rocky planets form
|width=65%|The {{w|Big Bang}} is a scientific theory that attempts to describe the very earliest conditions in our universe, but is also used informally as a synonym for the beginning of the universe. The early universe contained only simple elements such as hydrogen, but over time, star formation led to the creation of new, heavier elements, which eventually gave rise to planets with a rocky surface, which we call "land". It would have taken billions of years for the first such land-bearing planet to appear in the universe, so this time period could be considered "the time before land".
|-
|'''The time before bees'''
|Big Bang
|Ground-nesting bees evolve
|This time range also includes the formation of the Earth, a necessary precondition for bees to evolve. Any time before the evolution of bees could be considered "The time before bees".
|-
|'''The land before thyme'''
|Rocky planets form
|''Thymus'' genus diverges
|
|-
|'''Time for land bees!'''
|Ground-nesting bees evolve
|Now
|
|-
|'''Bees land on thyme'''
|''Thymus'' genus diverges
|Now
|}

The title text lists 2 places with the name "Beeland": [https://www.tripadvisor.com/Attraction_Review-g2108670-d2094291-Reviews-Beeland-Spillimacheen_Kootenay_Rockies_British_Columbia.html Spillimacheen, British Columbia] or [http://www.apartmajimozirje.si/en/beeland/ a chalet in Slovenia].

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

{{comic discussion}}

[[Category:Timelines]]
[[Category:Fiction]]
[[Category:Animals]]
[[Category:Puns]]

1932: The True Meaning of Christmas

2017-12-31T03:43:48Z

108.162.221.239:

{{comic
| number = 1932
| date = December 22, 2017
| title = The True Meaning of Christmas
| image = the_true_meaning_of_christmas.png
| titletext = They all made fun of Autometalogolex, but someday there will be a problem with Christmas that can only be solved if Santa somehow gets a serious headache, and then they'll see.
}}

==Explanation==

This is the first of two [[:Category:Christmas|Christmas comics]] in a row. It is making fun of the common trope in popular media that the {{tvtropes|TrueMeaningOfChristmas|true meaning of Christmas}} is about family, friends, and sharing the Christmas Spirit. It subverts the trope by suggesting that once the stories of the "True Meaning of Christmas" become sufficiently common, the real true meaning becomes to spread those stories. Thus the search for the "True Meaning of Christmas" is itself the meaning of Christmas, in a sort of "the journey is the reward" discovery.

In the last panel and title text, "Autometalogolex" can be broken down to its various prefixes and the root:
:"Auto-" - Greek meaning "self."
:"Meta-" - Greek meaning "after," "beyond," or "in reference to."
:"Logo-" - Greek meaning "word" or "speech."
:"Lex" - "lexis" is another Greek word meaning "word"; but in this case it is more likely to be a shortening of "lexicon" (another word for dictionary), or perhaps a reference to the process of "lexing" (lexical analysis), part of the process of computer analysis of text.
Thus, "Autometalogolex" literally means "A word that refers to itself in the dictionary." Or more precise it is "the act of looking up the definition of autometalogolex" which leads to a recursion as all ''meaning of Christmas'' stories do. Recursion and self-reference is a [[:Category:Self-reference|recurring theme]] in xkcd.

The term Autometalogolex might also refer to autological words, words that refer to a property of the word itself. ("noun" is a noun, "pentasyllabic" is pentasyllabic [has 5 syllables]). "Autometalogolex" is a a 'meta' version of the looking up (lex) of an autological word.

[[Cueball]] finally states that Autometalogolex is his least favorite {{w|Santa Claus's reindeer}} in addition to the common eight names ''Dasher'', ''Dancer'', ''Prancer'', ''Vixen'', ''Comet'', ''Cupid'', ''Donner'', and ''Blitzen''.

As the title text reveals this ninth reindeer could be a reference to {{w|Rudolph the Red-Nosed Reindeer}} which was not accepted by the others until Santa had problems and asked it to lead the other reindeer pulling the sleigh.

The title text may also imply the only effective outcome of Autometalogolex (or the newly defined Christmas) is giving headaches as with many self-referential concepts. As headaches generally are bad, Autometalogolex is not accepted, but - as in a typical Christmas story, here driven into the absurd realm - Santa needed a headache, and Autometalogolex was there to save the day.

==Transcript==
:[Cueball is talking to a guy wearing a Santa hat.]
:Cueball: You’re looking festive.
:Santa Hat: I love Christmas!
:Cueball: Really? Doesn’t seem like your kind of thing.
:Santa Hat: It’s our most meta holiday!

:[Same setting.]
:Cueball: How so?
:Santa Hat: All our Christmas stories now are about discovering the “true meaning of Christmas.”

:[The same setting in a frame-less panel where Santa Hat shrugs.]
:Cueball: Huh, yeah. And then sharing it with others.
:Santa Hat: At some point, that quest itself ''became'' the true meaning.

:[Same setting with Santa Hat holding a hand to his chin.]
:Cueball: Like a word whose definition is “the act of looking up the definition of this word.”
:Santa Hat: “Autometalogolex”?
:Cueball: My least favorite of Santa’s reindeer.

==Trivia==
*At the time this comic was released the expression ''Autometalogolex'' did not exist. But only a few hours later at {{w|Urban Dictionary}} this phrase got its first entries: [https://www.urbandictionary.com/define.php?term=Autometalogolex Urbandictionary Autometalogolex].
*Some believe that the Santa Hat character is actually [[Black Hat]], owing to the Santa hat in question being black (the character's behavior, and [[Cueball]]'s comment that Santa Hat doesn't seem to be the type to enjoy Christmas match Black Hat's personality perfectly). However, the Santa hat may actually be meant to be red but rendered as black because the comic is in black-and-white (although it's worth nothing that in [[361: Christmas Back Home]] and [[838: Incident]], Christmas clothing was shown as red, not black). Santa Hat's identity is therefore unclear. But that was of course [[:Category:Comics with color|Comics with color]] which is not the norm in xkcd, which is why there is a category for those. In black and white comics it makes no sense to discuss that a black Santa hat must be black.
**But already in the next comic where the "real" Santa is described his red Santa Hat is drawn black, thus proving that it is not a black hat because it is black in the comic.
**Since there are many comics with [[:Category:Multiple Cueballs|Multiple Cueballs]], it could just as well be Cueball with a Santa Hat and another guy asking him about it.
**As there is no way to decide, then the best description of this comic is that Cueball is talking to a guy with a Santa Hat.

{{comic discussion}}

[[Category:Christmas]]
[[Category:Comics featuring Cueball]]
[[Category:Characters with Hats]]
[[Category:Animals]]
[[Category:Self-reference]]
[[Category:Language]]

721: Flatland

2017-12-31T03:40:20Z

108.162.221.239: /* Explanation */

{{comic
| number = 721
| date = March 31, 2010
| title = Flatland
| image = flatland.png
| titletext = Also, I apologize for the time I climbed down into your world and everyone freaked out about the lesbian orgy overseen by a priest.
}}

==Explanation==

This comic is a reference to the satirical novel {{w|Flatland|''Flatland: A Romance of Many Dimensions''}}, in which a society of flat shapes live in a {{w|Two-dimensional space|2D}} world. Half the book is a direct satire of {{w|Victorian era|Victorian}} society, and the other half explores the experience of discovering a new dimension, where a sphere introduces a square (named A. Square) to {{w|Three-dimensional space|3D}}. [[Cueball]] appears to have taken the place of this sphere, and the comic takes place after the square knows the third dimension exists.

Humans will never fully be able to grasp the concept of a four spatial dimensions (at least not in the foreseeable future), but there are ways of squashing or slicing four dimensions to create partial visualizations of 4D space. {{w|Miegakure}} is a 4D game that uses cross-sections of 4D space. Cueball attempted to play it, but after having his mind blown, he gained more sympathy for A. Square, who'd had similar trouble understanding 3D. A. Square accepts his apology.

The joke here is that Cueball was being silly and drew lines on A. Square to make him look like {{w|SpongeBob SquarePants (character)|SpongeBob}}, which did not make the square happy. Cueball apologizes again.

The title text is a third apology for when Cueball crawled down into the second dimension. Being a stick figure, he is comprised of a circle and straight lines. In Flatland, circles are priests (Flatland's highest social level), and all women are lines; thus, to a watcher in Flatland, Cueball would look very much like a priest above many connected women, which may look like a lesbian orgy.

==UniXkcd==
This comic was released on March 31, 2010 and was still up on April 1st, 2010. On {{w|April_Fools%27_Day|April Fools' Day}} [[Randall]] altered the website to mimic a {{w|Unix}} command line interface. This interface is still available on [https://uni.xkcd.com uni.xkcd.com] and the source code is available on [https://github.com/chromakode/xkcdfools GitHub].
The terminal lists a few available commands:
* <code>next</code> shows the next comic. Shows the error "Time travel mode not enabled" on the last comic (see <code>enable time travel</code>).
* <code>prev</code> shows the previous comic.
* <code>first</code> shows the first comic.
* <code>last</code> shows the last comic.
* <code>display [number]</code> shows the comic with the specified number.
* <code>random</code> shows a random comic.
* <code>ls</code> shows the content of the current directory.
* <code>cat [filename]</code> shows the content of the file.
* <code>cd [directory]</code> changes to the specified directory.
But there are several undocumented commands as well:
* <code>a/s/l</code> [https://www.urbandictionary.com/define.php?term=a%2Fs%2Fl A/S/L] is not a unix command, but an acronym of Age/Sex/Location. The following replies are possible:
: <code>2/AMD64/Server Rack</code> answered as if the server replied.
: <code>328/M/Transylvania</code> answered by {{w|Dracula}}.
: <code>6/M/Battle School</code> answered by {{w|Ender Wiggin}} or another boy from battle school.
: <code>48/M/The White House</code> answered by {{w|Bacack Obama}} or another male of the same age in the White House.
: <code>7/F/Rapture</code>
: <code>Exactly your age/A gender you're attracted to/Far far away.</code> Requests for a/s/l are often not answered truthfully, but crafted to suit the one asking the question.
: <code>7,831/F/Lothlórien</code> answered by {{w|Galadriel}} or another elf.
: <code>42/M/FBI Field Office</code> answered by an FBI agent (referencing the old [http://tvtropes.org/pmwiki/pmwiki.php/Main/ThereAreNoGirlsOnTheInternet trope] that all girls on the internet are FBI agents impersonating them).
* <code>apt-get</code> replies "This APT has Super Cow Powers.". The <code>apt-get</code> command is part of the Debian package manager {{w|Advanced_Packaging_Tool|APT}}. This reply is one of the build in Easter eggs.
* <code>asl</code> same as <code>a/s/l</code>.
* <code>bash</code> replies "You bash your head against the wall. It's not very effective.". {{w|Bash}} is a shell for POSIX-based systems.
* <code>buy stuff</code> same as <code>cd store</code>.
* <code>cat [number]/alt.txt</code> displays the alt-text of the specified comic.
* <code>cat</code> (without a filename) will show "You're a kitty!" referencing [[231: Cat Proximity]].
* <code>cheat</code> promotes the [https://store.xkcd.com/ xkcd store].
* <code>clear</code> clears the screen.
* <code>date</code> replies "March 32nd".
* <code>dir</code> same as <code>ls</code>.
* <code>echo</code> replies "Echo ... echo ... echo ...". The {{w|Echo_(command)|echo}} command is used to print text to the terminal.
* <code>ed</code> replies "You are not a diety.". {{w|Ed_(text_editor)|ed}} is a very simple text editor. It is usually not considered very user friendly (see also <code>vi</code> and <code>emacs</code>).
* <code>emacs</code> replies "You should really use vim.". References [[378: Real Programmers]].
* <code>enable time travel</code> replies "TARDIS error: Time Lord missing.". A {{w|Doctor Who}} reference. See also the <code>next</code> command.
* <code>exit</code> will end the terminal session.
* <code>find kitten</code> showed the {{w|robotfindskitten}} game (the link to the Flash version no longer works, but an HTML version is available [http://robotfindskitten.org/play/robotfindskitten/ here]).
* <code>find</code> replies "What do you want to find? Kitten would be nice.".
* <code>finger</code> replies "Mmmmmm...".
* <code>fuck</code> replies "I have a headache.".
* <code>goto [any]</code> shows comic [[292: goto]] and asks if you meant <code>display</code> instead.
* <code>halp</code> same as <code>help</code>.
* <code>hello joshua</code> replies "How about a nice game of Global Thermonuclear War?". A reference to the {{w|WarGames}} movie.
* <code>hello</code> replies "Hello.". There is a second reply "Why hello there!" coded, but it is never used.
* <code>help</code> says "That would be cheating!".
* <code>hi</code> replies "Hi.".
* <code>hint</code> randomly replies "We offer some really nice polos.", "This terminal will remain available at xkcd.com/unixkcd/", "Use the source, Luke!" or "There are cheat codes.".
* <code>i read the source code</code> replies "<3".
* <code>irc [nick]</code> starts an {{w|IRC}} session on the xkcd channel on irc.foonetic.net.
* <code>kill</code> replies "Terminator deployed to 1984.". A reference to the {{w|The_Terminator|Terminator}} movie.
* <code>locate [filename]</code> is normally used to locate a file in a directory. It will give humorous results when searching for <code>ninja</code>, <code>keys</code>, <code>joke</code>, <code>problem</code> and <code>raptor</code>.
* <code>logout</code> same as <code>exit</code>.
* <code>lpr</code> replies "PC LOAD LETTER". {{w|Line_Printer_Daemon_protocol|lpr}} is a command to print documents. {{w|PC_LOAD_LETTER}} is a printer error.
* <code>make love</code> replies "I put on my robe and wizard hat.". <code>make love</code> is a standard unix joke, because the reply is "make: don't know how to make love.".
* <code>make me a sandwich</code> behaves like [[149: Sandwich]].
* <code>man [command]</code> show unhelpful information about the command (only <code>last</code>, <code>help</code>, <code>next</code>, <code>cat</code> or no command are support).
* <code>moo</code> replies "moo".
* <code>more</code> replies "Oh, yes! More! More!". The {{w|More_(command)|more}} command is used to paginate output.
* <code>nano</code> replies "Seriously? Why don't you just use Notepad.exe? Or MS Paint?". {{w|GNU_nano|Nano}} is another text editor for Unix systems (see <code>vi</code> and <code>emacs</code>).
* <code>ping</code> replies "There is another submarine three miles ahead, bearing 225, forty fathoms down.". The {{w|Ping_(networking_utility)|ping}} command used to measure round trip times to a destination. The name does indeed originate from {{w|sonar}} technology.
* <code>pwd</code> replies "You are in a maze of twisty passages, all alike.". The {{w|pwd}} command prints the current working directory (see <code>look</code>).
* <code>quit</code> same as <code>exit</code>.
* <code>reddit [number]</code> shows the [https://www.reddit.com/ Reddit] voting bar for the specified comic (or xkcd when no number is specified).
* <code>rm [filename]</code> will make it seem like you deleted the file.
* <code>serenity</code> replies "You can't take the sky from me.". This is a line from the Balad of Serenity from the {{w|Firefly_(TV_series)|Firefly}} TV series.
* <code>ssh</code> replies "ssh, this is a library.". {{w|Secure_Shell|ssh}} is the command to start a secure shell, but it also resembles the "{{w|Shh}}" sound.
* <code>su</code> replies "God mode activated. Remember, with great power comes great ... aw, screw it, go have fun.". The {{w|Su_(Unix)|su}} command is used to log in as super user, which gives you full and potentionally dangerous access to the system.
* <code>sudo [command]</code> executes the command with {{w|Superuser|root}} privileges.
* <code>sudo apt-get dist-upgrade</code> Returns "You are already running [OS].".
* <code>sudo apt-get moo</code> replies "Have you mooed today?" (apt-get Easter egg).
* <code>sudo apt-get update</code> Refreshes the package list so the system knows which updates are available.
* <code>sudo apt-get upgrade</code> shows a link to [http://abetterbrowser.org/ A Better Browser] on Internet Explorer and Firefox (< v3). On all other browsers it doesn't complain.
* <code>sudo make me a sandwich</code> behave like [[149: Sandwich]].
* <code>sudo poweroff</code> will shutdown the system.
* <code>sudo reboot</code> will restart the system.
* <code>sudo restart</code> same as <code>sudo reboot</code>.
* <code>sudo shutdown</code> same as <code>sudo poweroff</code>.
* <code>time travel</code> displays [[630: Time Travel]].
* <code>top</code> replies "It's up there --^". The {{w|Top_(software)|top}} command shows a table of processes. Here it is taken literally.
* <code>uname</code> replies "Illudium Q-36 Explosive Space Modulator". The Illudium Q-36 Explosive Space Modulator is an explosive device created by Marvin the Martian in the {{w|Looney Tunes}} series.
* <code>unixkcd</code> opens a new terminal window.
* <code>use the force luke</code> replies "I believe you mean source.". A reference to the {{w|The_Force_(Star_Wars)|Force}} in the {{w|Star Wars}} franchise.
* <code>use the source luke</code> replies "I'm not luke, you're luke!". An old programmes joke.
* <code>vi</code> reply "You should really use emacs.". References [[378: Real Programmers]].
* <code>vim</code> same as <code>vi</code>.
* <code>wget [url]</code> shows the content of the specified url. The {{w|wget}} command on unix will download the content and not show it.
* <code>who</code> replies "Doctor Who?". Another {{w|Doctor Who}} reference.
* <code>whoami</code> replies "You are Richard Stallman.". The {{w|whoami}} command lists the name of the current user.
* <code>write [nick]</code> same as <code>irc</code>.
* <code>xkcd</code> replies "Yes?".
* <code>xyzzy</code> replies "Nothing happens.". {{w|Xyzzy_(computing)|xyzzy}} is a magic word, originally used in the {{w|Colossal Cave Adventure}}.
* <code>your gay</code> replies "Keep your hands off it!".
There are also some other commands borrowed from a {{w|Zork}} like {{w|Text-based_game|text based adventure game}}.
* <code>look</code> describes your current surroundings.
* <code>go [direction]</code> moves you in the specified direction (<code>down</code> is also supported; however, it replies a different message).
* <code>light lamp</code> lights your lamp.
* <code>sleep [seconds]</code> sleeps for the specified time. Without specifying, the nap is 5 seconds.
You will be killed by a {{w|Grue_(monster)|grue}} if you didn't light your lamp when going south.
Going west repeatedly will list the refrain from the song {{w|Go_West_(song)|Go west}}.

The terminal also responds to the {{w|Konami code}} Up, Up, Down, Down, Left, Right, Left, Right, B, A. Entering this code repeatedly will transform all characters to upper case, add a gray text shadow, add an orange text shadow, shake the screen and add a background image of Richard Stallman from [[345: 1337: Part 5]].

==Trivia==
There is actually a SpongeBob episode featuring a flat creature that resembles a crude drawing of SpongeBob.

==Transcript==
:[Cueball encounters a square on the ground.]
:Cueball: Hey, A. Square. How's Flatland?
:Square: Still flat. What's up?
:Cueball: I just spent an hour playing a demo of this 4D game called Miegakure.

:[A character in Miegakure jumps around the 4D landscape.]
:Trying to jump from block to block in four dimensions hurt my brain.

:Cueball: So I apologize for giving you a hard time when you were slow to understand 3D space. I sympathize now.
:Square: It's okay.

:Cueball: Also, I apologize for drawing arms, legs, and eyes on you to make you look like SpongeBob. That was out of line.
:Square: Yes, it was.

{{comic discussion}}
[[Category:Comics featuring Cueball]]
[[Category:Comics with color]]
[[Category:Math]]
[[Category:Video games]]
[[Category:Homosexuality]]
[[Category:Sex]]
[[Category:April fools' comics]]

1935: 2018

2017-12-31T03:36:37Z

108.162.221.239: /* Explanation */

{{comic
| number = 1935
| date = December 29, 2017
| title = 2018
| image = 2018.png
| titletext = We should really start calculating it earlier, but until the end of December we're always too busy trying to figure out which day Christmas will fall on.
}}

==Explanation==

In this [[:Category:New Year|New Year comic]], [[Megan]] wonders if 2018 will be a {{w|Leap year|leap year}}. [[Cueball]] thinks 2018 will not be a leap year, and Megan responds that she "doubts anyone knows at this point." This appears to be a jab at the complexity of the leap year system. As Cueball says, leap years occur every four years (though there are a few exceptions), adding an extra day to account for the fact that Earth takes a bit longer than 365 days to orbit the Sun. Therefore, most years that are a multiple of four are leap years. As Megan says, this is easy for odd-numbered years, since no odd numbers are divisible by four. However, for even-numbered years, it isn't always obvious.

The last panel expresses a misunderstanding of modern {{w|Cryptography|cryptography}}, which relies on the fact that it is difficult to factorize large numbers. Megan is applying this concept to the year, claiming that it is hard to determine whether or not 2018 is a multiple of four and hence is a leap year. In reality, factorization is not needed here, since we already know the factor, which is four. Megan states that if it were possible to factor large numbers with a calculator, modern cryptography would collapse. While true, it is only true for truly large numbers (hundreds of digits), and no factorization is needed in this case.

At the end of the strip, Megan hopes the answer can be {{w|Brute-force attack|brute-forced}} by February. Brute force is a method of breaking cryptography by trying every possible option until one works. This is a misdirection upon misdirection, in that even if we needed to factorize 2018 (which we don't), the simplest brute forcing algorithm would only need to try 43 numbers - from 2 to square root of 2018 (44). In cryptography, the algorithms use numbers much, much bigger than 2018 -- on the order of hundreds (or even thousands) of digits.

The title text refers to calculating which day of the week {{w|Christmas}} (in western countries) will fall on. Given that any calendar will easily tell you, this is not a difficult thing to calculate. Also it always falls on December 25th, and not like, for instance, Easter which date jumps from year to year. But nevertheless December 25th is either the 359th or the 360th (leap years) day of the year and so the day of the week could be different.

==Transcript==

:[Megan is walking.]
:Megan: I wonder if 2018 will be a leap year.

:[Now it turns out that Cueball walks behind Megan.]
:Cueball: ...it won't be, right?
:Megan: I doubt anyone knows at this point.

:[Same scene in a frame-less panel.]
:Cueball: No, it's definitely not. Leap years are divisible by 4.
:Megan: Right, and for odd numbers, that's easy.
:Megan: But 2018 is even.
:Megan: 50/50 chance.

:[Zoomed-out view with both walking in silhouette on a dark slightly curved ground.]
:Cueball: I can settle this with a calculator.
:Megan: No way. If it were easy to factor large numbers like that, modern cryptography would collapse.
:Cueball: I see.
:Megan: I just hope we manage to brute-force it by February.

==Trivia==
*Released on Friday, December 29, this is the last comic of 2017. The next scheduled comic will be on New Year's Day of 2018.

*Every year that is exactly divisible by four is a leap year, except for years that are exactly divisible by 100, but these centurial years are leap years if they are exactly divisible by 400. For example, the years 1700, 1800, and 1900 were not leap years, but the years 1600 and 2000 were.

*2018 is not divisible by 4, so the year is not a leap year. 2016 and 2020 are leap years. Assuming your calendar is Gregorian! A year is roughly 365.2422 days long. (Actually, also the case if it is 2018 on the old Julian calendar. The century year rules for leap years are different on the Gregorian calendar from the Julian, but the non-century year rules are the same).

*{{w|Eastern Christian Churches}} celebrate Christmas also on December 25 but of the older Julian calendar, which currently corresponds to January 7 in the Gregorian calendar.

*This is the third year in a row with New Year's comics with only the year used as the title, before that there were two more comics with such titles, but those two (and thus the first three) were only released in the even years: [[998: 2012]] in 2012, [[1311: 2014]] in 2014, [[1624: 2016]] in 2016 and [[1779: 2017]] in 2017.

{{comic discussion}}

[[Category:New Year]]
[[Category:Comics featuring Megan]]
[[Category:Comics featuring Cueball]]
[[Category:Comics sharing name|2017]]
[[Category:Math]]
[[Category:Time]]
[[Category:Cryptography]]

Talk:1930: Calendar Facts

2017-12-18T22:47:17Z

108.162.221.239:

Shouldn't it be "libration" not "libation"? Pretty sure drinking has nothing to do with it. Also pretty sure this is a mistake and not a clever alteration. [[Special:Contributions/162.158.62.57|162.158.62.57]] 16:41, 18 December 2017 (UTC)
:No, it's a clever alteration because "libration" is listed right above it. --[[User:Videblu|Videblu]] ([[User talk:Videblu|talk]]) 16:45, 18 December 2017 (UTC)
::That's just a mistake - he meant to write 'vibration'[[Special:Contributions/141.101.76.16|141.101.76.16]] 16:48, 18 December 2017 (UTC)
:::'Vibration' wouldn't make any sense, 'libation' is at least humorous, I vote it was no mistake. [[Special:Contributions/172.68.54.64|172.68.54.64]] 18:00, 18 December 2017 (UTC)

I formatted the transcript into a bullet tree since I thought it was the closest equivalent you can get in plain text to the branching flowchart deal in the comic. I'm open to alternative suggestions. The biggest problem I encountered, and one I'd like to see resolved, is what to do in the case where two branching sections butt up against each other, e.g. winter/summer and solstice/Olympics. I used an arrow symbol ("→") on an in-between line just to separate the set of bullets, but if someone wants to change that, I'm up for it. [[User:Kenbellows|Kenbellows]] ([[User talk:Kenbellows|talk]]) 18:04, 18 December 2017 (UTC)
:I find the bullet tree legible for the last few long lines, but it's hard to follow a single path. I was thinking of using (option 1|option 2) syntax, but that would probably look messy too. [[Special:Contributions/162.158.91.29|162.158.91.29]] 18:10, 18 December 2017 (UTC)

Random error noticed - the line connecting "International Date" and "Mason-Dixon" to "Line" is drawn in the wrong color. [[Special:Contributions/162.158.75.136|162.158.75.136]] 18:57, 18 December 2017 (UTC)

Isn't the point with this comic that there is at least one valid path for every included element? I don't think Randall intended it to be a factorial combination because as the explanation suggests, most would be wrong/absurd/silly. But why not instead try to find some invalid element when it can be included in any possible path from end to end? Toyota Truck Month or Shark Week might not happen next year, who knows? Can anyone find any element that has no valid path at all? If not, then maybe the main explanation should be updated to fit the model recommended here.[[User:Lunar7|Lunar7]] ([[User talk:Lunar7|talk]]) 20:05, 18 December 2017 (UTC)

== Generators ==

https://staab.github.io/xkcd-1930/

: Not sure who's responsible for this, but there seem to be a few errors. "Might (not happen/happen twice) this year" is missing "this year", and "the (harvest/super/blood) moon" is similarly missing "moon". Also, I see a part "happens at the same time every year" that I don't see in the comic. Are there any other additions; and is there a way to find them other than keep refreshing? -- [[User:Angel|Angel]] 18:40, 18 December 2017 (UTC)

:: Checked the source; looks like "at the same time" replaces "at the wrong time". Also, some of the options are missing a "." between the main tree and the title text or at the end of the sentence. (And for some reason every time I go to edit this talk page, the wiki logs me out) -- [[Special:Contributions/162.158.91.167|162.158.91.167]] 18:48, 18 December 2017 (UTC)

: The source is on [https://github.com/staab/xkcd-1930 github] - you can add pull requests to fix errors (I'll take care of the aforementioned errors).

Here's mine.

http://www.hearn.to/calendar.html

[[Special:Contributions/172.68.142.65|172.68.142.65]]

Here's one I wrote on jsFiddle. Glad I'm not the only one who read this and immediately thought, "I must code this!" [[Special:Contributions/172.68.34.64|172.68.34.64]] 21:29, 18 December 2017 (UTC)

https://jsfiddle.net/qa290hss/

== Equinox ==

I don't think this is the correct definition for equinox, the plane comprising the Earth orbit around the Sun is never perpendicular to the Earth's axis. During the equinox the sun rays arrive to the Earth perpendicular to the equator line, this would be better. [[Special:Contributions/172.68.62.238|172.68.62.238]] 22:10, 18 December 2017 (UTC)CBM

I agree with the comment above; the Earth's axis is always tilted 23 degrees from the plane of the orbit. There are times the North pole is tilted toward the Sun and times it is tilted away from the Sun. Twice a year (at the equinoxes) the tilt is perpendicular to the Sun. [[Special:Contributions/108.162.221.239|108.162.221.239]] 22:47, 18 December 2017 (UTC)

== Daylight Saving Time ==
Twice the description references locations that don't follow the common DST plan as 'other than the natural latitude would suggest'. The ''longitude'' would suggest a time zone, not the latitude. [[Special:Contributions/108.162.221.239|108.162.221.239]] 22:47, 18 December 2017 (UTC)