explain xkcd - User contributions [en]

599: Apocalypse

2016-08-03T16:37:18Z

108.162.210.210: /* Explanation */ now -> know

{{comic
| number = 599
| date = June 19, 2009
| title = Apocalypse
| image = apocalypse.png
| titletext = I wonder if I still have time to go shoot a short film with Kevin Bacon.
}}

== Explanation ==
This comic begins with the beginning of the {{w|Apocalypse}}, hence the title. It is depicted, properly, with a very dystopian color picture with several yellow burning {{w|meteors}} striking down from the blood red sky, towards a black, red, orange and yellow ground. The way the panels are drawn below makes a transition from this dark image to a normal comic, with the first normal panel being superimposed on the dark image.

In this image [[Beret Guy]] shouts out '''The apocalypse!''' And then he continues to explain what this will mean: ''The skies burn, the seas turn to blood, and the dead walk the earth!''

All three sentences are attributed to the apocalypse, but it seems that the first one about the sky burning, actually comes from a translation of one of {{w|Nostradamus}} predictions, which has among other been used to "{{w|Nostradamus_in_popular_culture#September_11.2C_2001|predict 9/11}}". In {{w|Revelation 16}} from the bible about the {{w|Seven bowls}}, which are a set of seven plagues of God's wrath poured over the wicked towards the Apocalypse, the {{w|Seven_bowls#Second_Bowl|second bowl}} describes that ''{{w|Revelation_16#Structure|The Sea Turns to Blood}}''. The {{w|Universal resurrection|resurrection of the dead}} is from the biblical version of the Apocalypse, the {{w|Last Judgment}}.

After Beret Guy has announced this, he runs into [[Cueball]] who has heard part of this, but he is only interested in the last part and asks to check if he understood correctly that the dead will walk the earth. When this is confirmed Cueball becomes very busy.

He runs to his office and quickly writes a scientific math paper, then runs as fast as he can to the math department and get his colleagues to sign it. Then he runs to a cemetery where the dead are rising finds the one he searched for and asks the resurrected man if he is Erdős. When confirmed he ask him to sign the math paper.

{{w|Paul Erdős}} (26 March 1913 – 20 September 1996) was a Hungarian mathematician who (according to Wikipedia) published more papers than any other mathematician in history, working with hundreds of collaborators.

There is an in-joke developed among mathematicians called the {{w|Erdős number}} (similar to a Bacon number for film actors, referenced in the title text, see below). By definition, Erdős has an Erdős number of 0. Everyone who has co-written a mathematical paper with Erdős has an Erdős number of 1. Everyone who collaborated with them (but not Erdős himself) is assigned an Erdős number of 2. In general, if ''k'' is the minimal Erdős number of all the people you've written papers with, your Erdős number is ''k'' + 1. The Erdős number is the length of the shortest "chain" from you to Erdős.

Thanks to collaboration between mathematicians and other researchers, many people in science and medical research now have Erdős numbers. Not everyone has an Erdős number, though; people without any chain linking them to Erdős have an undefined Erdős number. For example, most people who are not mathematicians or scientists do not have an Erdős number. Paul Erdős described people who had stopped doing mathematics as "dead."

By this trick Cueball thinks that he and his colleagues will now all have a an Erdős number of 1. The joke being that he would be using his last few hours in this life to write a math paper just to improve his and his friends Erdős number.

There is, however, many problems with his idea, even assuming the dead will walk the earth on that day. First of all having your name on a piece of paper with Erdős signature does nothing for your Erdős number. It needs to be a {{w|Scientific_literature#Scientific_article|scientifically valid paper}}, published in a {{w|peer reviewed}} {{w|scientific journal}}. And given that the apocalypse is happening, there seems no time, chance or reason to publish any more math papers.

Even if there where time, it would not count for much to have someone sign a math paper they haven't even read, let alone had anything to do with the actual writing and research. The same would be true for the other five mathematicians who signed it. But of course many papers have coauthors who did not do much more than work in the same department as the person who actually wrote the paper (a sad but true fact).

Furthermore even if it did count, they will not be able to take the paper with them into the afterlife, and thus since no one would have had time to read the paper, no one would know they had an Erdős number of 1. In the afterlife they could all say that they had such a number, but then again everyone else with such an interest could do the same, since no one could prove otherwise. Of course if you end up in the same part ({{w|Heaven}} or {{w|Hell}}) of the {{w|afterlife}} as Erdős he could confirm or deny the claim, but that would probably not help Cueball and his friends, since he could tell the truth about their paper.

That the whole comic is about the Erdős number, and not just Erdős signature, is made clear in the title text which refers to a similar (and less esoteric) meme called "{{w|Six degrees of Kevin Bacon}}", or simply Bacon numbers. This time, the chain's center is actor {{w|Kevin Bacon}}, and the links are formed by two people appearing in the same movie. Unlike Erdős, Kevin Bacon is not dead, so those of you wishing to get a Bacon number of 1 still have a chance.

In the title text Cueball thus wonders if there is still time for him to run on an make a short film with Kevin Bacon, now he has used so much time on improving his Erdős number. Again, if the film hasn't been shown to the public it would not count for anything...

One of the mathematical scribbles appearing in panel 5 shows the square root of 163, which may be a reference to {{w|Ramanujan's constant}}.

[[403: Convincing Pickup Line]] has a parody of the Erdős collaboration graph.

==Transcript==
:[The first panel is very large and shows a dark scene with one large meteor in front and four smaller in the background showering the darkened earth. They are all five black with yellow fire around them and a fire trail behind them, and all are flying from the top left corner and down towards right. The sky at the top is pitch black, but then the sky turns blood red under dark clouds. Two large mountain peaks, one almost pyramid shaped, are shown to the left and to the right there are two smaller peaks towards the distant horizon. The mountains and the ground around them are mainly black, but with red, orange and yellow streaks spread all over the black area beneath the mountain peaks, maybe indicating fire or lava, or reflections in water or blood. At the bottom right corner a normal white panel is superimposed on this apocalyptic image.]

:[The smaller panel at the bottom of the first is halfway over the first panel, haflway below, and only to the right of the middle of the first panel. Beret Guy is running towards left, with his arms raised in the air.]
:Beret Guy: The Apocalypse! The skies burn, the seas turn to blood, and the dead walk the earth!

:[From here a normal sequence of panles in three rows begin beneath the second panel. This leaves a gap between the apocalyptic panel and the third row of panel, on the left side where the 2nd panel did not reach over. In this panel Beret Guy (coming from the right) finds Cueball.]
:Cueball: The dead what?
:Beret Guy: Walk the earth!

:[Cueball running right in a thin panel.]
:Cueball: I have to go.

:[Cueball sitting on a chair at a table scribbling vigorously and nosily with a pen on a paper. Mathematical symbols appear above Cueball's head, including a summation from i=0 to n, a logarithm of n and the square root of a number.]
:<big>∑</big>ni=0ik1/i log(n)
:√163
:''Scribble''
:''Scribble''

:[Cueball running right again, in a thin panel, pen and paper in hand.]

:[Cueball opening door with label:]
:Math Dept
:Cueball: The dead return!
:Cueball: Everyone, quick, get your names on here!

:[Cueball stand on the left side of a table looking left over his shoulder. Five people are lining up to sign the paper lying on the right side of the table. The first who signs with a pen is a woman with long white hair, then in line follows Megan, a Cueball-like guy, Ponytail and another Cueball-like guy who stand with one hand to his chin looking right, away from the other.]
:Woman with long white hair: At last!
:Guy looking right: I hope there's time!

:[Cueball running right in yet a thin panel, with pen and the paper flowing behind him.]

:[Cueball walks right with the paper and pen in his hand as he arrives at at a cemetery as revealed by an old worn sign. Scary sounds appear off-panel right.]
:Sign: Cemetery
:Rising dead (off-panel): ''Hurrghhh''

:[Cueball, still going right, arrives at a grave, pen in hand and the other hand almost outside the panel, but with a corner of the paper just visible. The grave has a large gravestone to the right and in front of it there is a Cueball-like guy rising up from the ground using his arms to push up on the base of the stone and the small pile of earth towards Cueball. The guy looks very worn, with dirt on his head and scratches on his cheek.]

:[Cueball bends a little down and offers pend and paper to the raised dead man who looks up at him when he is addressed-]
:Cueball: Paul Erdős?
:Erdős: Yes?
:Cueball: We need you to sign this.

{{Comic discussion}}

[[Category:Comics with color]]
[[Category:Comics featuring Beret Guy]]
[[Category:Comics featuring Cueball]]
[[Category:Comics featuring Megan]]
[[Category:Comics featuring Ponytail]]
[[Category:Multiple Cueballs]]
[[Category:Comics featuring real people]]
[[Category:Math]]
[[Category:Zombies]]

Talk:1557: Ozymandias

2015-07-29T16:48:35Z

108.162.210.210:

Look upon this comment and despair! {{unsigned ip|173.245.50.164}}
: The fact that the true author of this comment may never be known is reason enough to despair.[[Special:Contributions/173.245.55.66|173.245.55.66]] 14:35, 29 July 2015 (UTC)
: An unrelated but interesting piece of trivia about Ozymandias: "Ozymandias" is the Greek name of the pharaoh Ramesses II, one of the most famous of the Egyptian pharaohs, who built many monuments that still stand today. So the poem, which has a ruler whose monument has crumbled and who is implied to be nearly forgotten, is in fact completely inaccurate! [[User:JoeNotCharles|JoeNotCharles]] ([[User talk:JoeNotCharles|talk]]) 15:23, 29 July 2015 (UTC)
:: Perhaps the Ozymandias King of Kings from the poem is not the same one as Ozymandias the pharaoh? So he's doubly forgotten, because he has a more famous [http://en.wiktionary.org/wiki/namefellow namefellow]! [[User:Leoboiko|Leoboiko]] ([[User talk:Leoboiko|talk]])

So... [http://dwarffortresswiki.org/index.php/Planepacked Planepacked]? [[Special:Contributions/173.245.50.145|173.245.50.145]] 05:44, 29 July 2015 (UTC)

The page seems to give a description, but not an explanation of the joke. I still don't get it! Why has Ozymandias been singled out for this treatment? Is there some way in which recursion is particularly appropriate or inappropriate in this case, or has it just been selected arbitrarily? Is the whole joke that recursion is inherently funny? Normally when recursion is used in XKCD it's making a larger point, or cleverly riffing on something in particular. This isn't just Describe XKCD, so I'd love to see an explanation of this comic. [[Special:Contributions/141.101.99.47|141.101.99.47]] 09:35, 29 July 2015 (UTC)

:The poem Ozymandias, like the statue of the king,can be thought of as a pinnacle of achievement for its civilizarion- in this case, English civilization. So it is entirely possible that one day, after the fall of this civilization, the poem will fill the same role for it that the statue filled for Ozymandias' (fictional) civilization. [[User:Bbruzzo|Bbruzzo]] ([[User talk:Bbruzzo|talk]]) 15:33, 29 July 2015 (UTC)

:May it be that Ozymandias is chosen because of Smith’s poem, where at last London has vanished, suggesting that Shelley’s poem is the last remains of British civilization? --[[Special:Contributions/162.158.91.193|162.158.91.193]] 10:04, 29 July 2015 (UTC)

:I think Ozymandias was chosen because its opening is particularly famous. Even people who don't know much about poetry are often passingly familiar with it, and there's something funny about playing with well-known classics. And yes, I do believe the joke is that infinite recursion is inherently funny. There's a long tradition of these recursion-jokes among computer scientists and math people (like the "GNU" acronym, or recursive index references), with precedents in xkcd itself. [[User:Leoboiko|Leoboiko]] ([[User talk:Leoboiko|talk]])

In Germany, we have a childrens’ song „Ein Mops kam in die Küche“, which translates as follows (there are slightly different versions, though):

A pug came into the kitchen / and stole an egg from the chef. / Then the chef took his knife / and mashed the pug. // Then many pugs came / to his grave / and set a memorial for him, / where these words were written: // “A pug came into the kitchen …”

Maybe something similar exists in English? --[[Special:Contributions/162.158.91.193|162.158.91.193]] 10:04, 29 July 2015 (UTC)

:We have:

: This is the song that doesn't end, / Yes, it goes on and on, my friend, / Some people started singing it not knowing what it was, / And they'll continue singing it / Forever, just because [repeat] :''— [[User:Tbc|tbc]] ([[User talk:Tbc|talk]]) 12:34, 29 July 2015 (UTC)''

:There's also:
::I know a song that gets on everybody's nerves, everybody's nerves, everybody's nerves,
::I know a song that gets on everybody's nerves and this is how it goes...[repeat] {{unsigned ip|197.234.243.249}}

:: In Dutch: "Het was nacht, stikdonkere nacht. Veertig rovers zaten rond een vuur. De roverhoofdman stond op een zei: "Het was nacht, stikdonkere nacht... " "
:: Which translates to something along the lines of: "It was night, a pitchblack night. 40 robbers sat round a fire, their leader stood up and said: "It was night, a pitchblack night..." "
:: Sometimes the fire is replaced by the shadow of a dandelion. "..Forty robbers sat in the shadow of a Dandelion, their Chief stood up and said: "It was a dark night, forty robbers sat in the shadow of a dandelion", etc. -- [[Special:Contributions/141.101.104.67|141.101.104.67]] 13:01, 29 July 2015 (UTC)

::: The version I learned is: It was a dark and stormy night / and the good ship Marigold sailed the stormy seas. / The captain staggered down the steps / and said, "Mate, tell us a story!" / and the mate began, / "It was a dark and story night... --[[User:Mflansburg|Mflansburg]] ([[User talk:Mflansburg|talk]]) 15:44, 29 July 2015 (UTC)

:I've heard a very long infinitely recursive song in English, which is a variant of "The Bear Went Over the Mountain". The standard lyrics are:

:: The bear went over the mountain, the bear went over the mountain, the bear went over the mountain to see what he could see / And all that he could see, and all that he could see / Was the other side of the mountain, the other side of the mountain, the other side of the mountain, and that's what he could see.

: Well, the infinite variant goes:

:: The bear went over the mountain the bear went over the mountain, the bear went over the mountain to see what he could see / And all that he could see, and all that he could see / Was a valley in the mountain, a valley in the mountain, a valley in the mountain, and that's what he could see
:: The bear went over the mountain the bear went over the mountain, the bear went over the mountain to see what he could see / And all that he could see, and all that he could see / Was a lake in the valley, a lake in the valley, a lake in the valley, and that's what he could see
:: ... a sailboat on the lake ...
:: ... a man in the sailbot ...
:: ... pants on the man ...
:: ... a pocket in the pants ...
:: ... a nickel in the pocket ...
:: ... a beaver on the nickel ... (Note: I just realized this line only works in Canada, where the five cent coin has a picture of a beaver on it.)
:: ... a hair on the beaver ...
:: ... a flea on the hair ...
:: ... cells in the flea ...
:: ... a prisoner in the cells ...
:: ... pants on the prisoner ...
:: ... a pocket in the pants ...
:: etc.

: I prefer a slightly shorter version which goes from "a pocket in the pants" to "a dime in the pocket", then "a sailboat on the dime" (which again only works in Canada), and back to "a man in the sailboat". [[User:JoeNotCharles|JoeNotCharles]] ([[User talk:JoeNotCharles|talk]]) 15:14, 29 July 2015 (UTC)

::
Note that the recursion doesn't necessary be infinite. The list of travelers who met each other can have fixed length, for example 10. Imagining that the list is infinite is the joke. -- [[User:Hkmaly|Hkmaly]] ([[User talk:Hkmaly|talk]]) 10:06, 29 July 2015 (UTC)

Should we mention {{w|quines}}, which occur when lists like this end after two iterations, as "Yo, I'm MC Quine and I'm here to say/'Yo, I'm MC Quine and I'm here to say'!" {{unsigned|FourViolas}}

: That's not exactly a quine - a quine is a set of instructions which, when followed, recreates the instructions. If you take MC Quine's quote and write it out, you get just, "Yo, I'm MC Quine and I'm here to say", which doesn't contain the second repetition. To be a quine, you need to find some way that taking just the quoted part will automatically expand to the full statement plus the quote.

: A closer example of a quine: "Q: Pete and Re-Pete were sitting on a bridge. Pete fell off. Who was left? A: Repeat." If you take the answer "repeat" as an instruction, you would repeat the joke, recreating it completely. [[User:JoeNotCharles|JoeNotCharles]] ([[User talk:JoeNotCharles|talk]]) 15:19, 29 July 2015 (UTC)

This reminds me of Theodor Storm's "Schimmelreiter" ([https://en.wikipedia.org/wiki/The_Rider_on_the_White_Horse "The Rider on the White Horse"]) which descends through three nested levels of narrators before it comes to the real story. --[[User:Ulm|ulm]] ([[User talk:Ulm|talk]]) 13:56, 29 July 2015 (UTC)

One connection between recursion and Ozymandias is the phrase "Quis custodiet ipsos custodes?" aka "Who watches the watchmen?" and the character in ''The Watchmen'' named Ozymandias. [[Special:Contributions/108.162.221.51|108.162.221.51]] 14:42, 29 July 2015 (UTC)

Nested Shelleys? Maybe associaing Shelley with shells could be part of the joke? [[Special:Contributions/108.162.216.115|108.162.216.115]] 16:02, 29 July 2015 (UTC)

I keep trying to see 10, but I keep counting 11 syllables in each line with the exception of the last one. [[Special:Contributions/108.162.210.210|108.162.210.210]] 16:48, 29 July 2015 (UTC)

1547: Solar System Questions

2015-07-06T17:21:22Z

108.162.210.210: /* Explanation */ Dude, don't push young earth here (Comic 154)

{{comic
| number = 1547
| date = July 6, 2015
| title = Solar System Questions
| image = solar_system_questions.png
| titletext = My country's World Cup win was exciting and all, but c'mon, what if the players wore nylon wings and COULD LITERALLY FLY?
}}

==Explanation==
{{incomplete|Created by a BOT - Please change this comment when editing this page.}}

This comic is a list of questions which Randall has about the Solar System, which at first glance may appear to be things that Randall would like to learn about.
In actual fact most of the questions have not been satisfactorily answered or proven by anyone in the scientific community.

{| class="wikitable"
|-
! Question given
! Answer given by Randall (in Red)
! Comments
|-
| Why is the the Moon so blotchy?
| Lava
| "the the" could be a Randallism (intended or unintended).
|-
| Why are all the blotches on the near side?
| ...
| The nearside of the Moon is dominated by the blotchy 'seas' (volcanic flats), the far side by craters. Possibly an overabundance of craters obliterate the blotches, and the far side was always more 'exposed' to impacts.
|-
| Did Mars have seas?
| Yes (briefly?)
| Recent explorations have confirmed there was once standing water (not just occasional flowing water), but not yet how long, save that it created the sedimentary layers that we have seen.
|-
| Was there life on Mars?
| ...
| One of the big mysteries, not yet answered.
|-
| What's Titan like?
| Cold, yellow, lakes + rivers (methane)
|
|-
| What was Earth like during the Hadean?
| ...
| {{w|Hadean}}
|-
| Is the Oort Cloud a real thing?
| ...
| The {{w|Oort Cloud}} is a theoretical spherical cloud of icy planetsimals centred around our sun.
|-
| Why is the Sun's corona so hot?
| Something about magnets?
| The {{w|corona}} of the sun is hotter than it theoretically should be. The looping magnetic fields in this area could be responsible.
|-
| What are comets like?
| Precipitous
| The {{w|Philae (spacecraft)|Philae lander}} is next to a cliff...
|-
| Where's Philae, exactly?
| ...
| ...but we're not sure ''which'' cliff.
|-
| What's Pluto like?
| rowspan="2" | [Soon!]
| rowspan="2" | A probe may be about to answer both of these questions.
|-
| What's Charon like?
|-
| Why don't we have in-between-sized planets?
| ...
| There is a size-gap between the rocky planets (up to Earth size) and the gas giants
|-
| What's Ceres like?
| [Working on it!]
| Another probe
|-
| Why is Europa so wierd-looking and pretty?
| Ice over a water ocean
|
|-
| Why is Io so weird-looking?
| Sulfur volcanoes (? in the wrong places?)
|
|-
| Why are so many Kuiper Belt objects red?
| ...
| {{w|Kuiper Belt}}
|-
| What are those spots on Ceres?
| ...
| {{w|Ceres (dwarf planet)|Ceres}}
|-
| What's in the seas under Europa's ice?
| ...
| {{w|Europa (moon)|Europa}}
|-
| Which of the other moons have seas?
| Several
| (Partial/initial list possible? Definition of 'seas' would affect this.)
|-
| What are the big white things in Titan's Lakes?
| ...
| {{w|Lakes of Titan}}
|-
| What do Jupiter's clouds look like up close?
| ...
|
|-
| What's all that red stuff in the Great Red Spot?
| ...
|
|-
| What's pushing the Pioneer Probes?
| Heat from the RTG
| Discussed as the {{w|Pioneer anomaly}}. RTG stands for {{w|Radioisotope Thermoelectric Generator}}.
|-
| What pushes spacecraft slightly during flybys?
| ...
| The related {{w|Flyby anomaly}}.
|-
| Where are all the Sun's Neutrinos?
| Oscillating
|
|-
| Why is there so much air on Titan?
| ...
|
|-
| Why <sic? Where?> does the Kuiper Belt Stop?
| ...
| A reference to the {{w|Kuiper Cliff}}.
|-
| Why is Iapetus weird-colored?
| ...
|
|-
| Why does iapetus have a belt?
| ...
|
|-
| What's the deal with Miranda?
| ...
| Miranda is the smallest of Uranus's five round satellites. Possibly also a [[Category:Firefly|Firefly reference]] since Miranda is the name of a planet in ''Serenity'', a film in the ''Firefly'' series.
|-
| Did Uranus and Neptune change places?
| ...
| The {{w|Nice model}} is a theory of how our solar system formed, which suggested the possibility of Uranus and Neptune having swapped places before reaching their current positions. Work by Professor S. Desch [http://dusty.la.asu.edu/~desch/publications/2007/Desch2007.pdf| also came to this result].
|-
| Did the Late Heavy Bombardment happen?
| ...
|
|-
| Did life start before it?
| ...
|
|-
| Is Europa covered in Ice Spikes?
| ...
|
|-
| Why haven't we build a big inflatable Extreme Sports Complex on The Moon?
| ...
|
|-
| (Titletext) My country's World Cup win was exciting and all, but c'mon, what if the players wore nylon wings and COULD LITERALLY FLY?
| ...
| {{w|2015 FIFA Women's World Cup}}
|}

==Transcript==
{{incomplete transcript}}

{{comic discussion}}