explain xkcd - User contributions [en]

2467: Wikipedia Caltrops

2021-05-25T18:02:11Z

Aid1043: Reordered the explanation to get to the point more quickly

{{comic
| number = 2467
| date = May 24, 2021
| title = Wikipedia Caltrops
| image = wikipedia_caltrops.png
| titletext = Oh no, they set up a roadblock which is just a sign with the entire 'Czech hedgehog' article printed on it.
}}

==Explanation==
{{incomplete|Created by A WIKIPEDIA CRAWL INEVITABLY REACHING "PHILOSOPHY". Please mention here why this explanation isn't complete. Do NOT delete this tag too soon.}}
[[Cueball|Cueball's]] car has a collection of Wikipedia links spilling out of the trunk, meant to stop [[Hairy]] who's in the following car. The idea is that by dropping a series of interesting links, one could stop someone else's movement as they take the time to go through them all, provided that they are also easily distracted. This is analogous to the {{w|caltrops}} mentioned in the title; caltrops are small, spiked implements that are scattered on a road to slow down someone pursuing you. Hence the title of ''Wikipedia Caltrops''.

Wikipedia is also a website that is notorious for having many links to other pages, which may result in a "wiki walk", a dilemma for [[Randall]] that has been discussed previously in [[214: The Problem with Wikipedia]] (and separately with TV Tropes in [[609: Tab Explosion]]).

This strategy is similar to a weaponized version of [[356: Nerd Sniping]], using the high levels of focus that tend to come along with nerdy interests against someone. Munroe apparently reasons that, because these links would stop him in his tracks, they might do the same for a given target.

The Wikipedia links include:
* {{w|1808 mystery eruption}}: A conjectured volcanic eruption
* {{w|1916 Cumberland vs. Georgia Tech football game}}: The most uneven college football game in history
* {{w|1994 Caribbean Cup#Anomaly}}: A soccer game where group stage qualification rules had unintended consequences
* {{w|American death triangle}}: An unsafe type of rock climbing anchor
* {{w|AVE Mizar}}: A 1970s flying car
* {{w|Bald-hairy}}: A Russian political theory about state leaders' hairstyles
* {{w|Boeing YAL-1}}: A laser weapon mounted on a military aircraft
* {{w|Bubbly Creek}}: A stretch of river in Chicago featured in ''The Jungle''
* {{w|Burned house horizon}}: An area where Neolithic people burned their settlements
* {{w|Defence Scheme No. 1}}: A 1920s plan for Canada to attack the USA
* {{w|Elsagate}}: A YouTube controversy involving inappropriate videos being categorised as child-friendly
* {{w|Fastest animals#Invertebrates}}: Very fast insects, and some squid
* {{w|Flying ice cube}}: An effect in molecular dynamics simulations
* {{w|Future of Earth#Introversion}}: A theory that the continents will all drift back together
* {{w|Hairy Hands}}: A ghost story in Dartmoor, England
* {{w|January 0}}: December 31st in some software programs
* {{w|List of fictional colors}}: Impossible colours in fiction
* {{w|List of unexplained sounds}}: Mostly detected by NOAA, includes the Bloop
* {{w|Talk:List of U.S. states and territories by elevation#Delaware - Ebright Azimuth}}: A user argues the highest point in Delaware isn't Ebright Azimuth, but a trailer park
* {{w|Mosquito laser}}: A proposed device for killing mosquitoes
* {{w|Pheasant Island}}: An island shared equally between France and Spain
* {{w|Time in Australia#Anomalies}}: Places in Australia which do not use the expected time zone
* {{w|Timeline of the far future}}: Scientific speculation
* {{w|Walkalong glider}}: A type of unpowered model aircraft

Mentioned in the title text, a "{{w|Czech hedgehog}}" is an anti-tank obstacle made of metal, and would be an effective roadblock, however a sign describing it would not impede most traffic, {{Citation needed}} only for those distracted as easily as Randall.

==Transcript==
:[Cueball drives a car, followed by another car driven by Hairy. Cueball is leaning on the open window looking back as 24 large paper slips with Wikipedia links are flying out of the open trunk of the car. They extend to the front of Hairy's car, obscuring that all the way up to Hairy's position in the car. None of the links can be read in full, and only on a few can parts of the actual link be seen. Many has only part of the pages title visible, some parts are obstructed partly by other slips in front of them or they have not entirely left the trunk. In once case the link is so long that it has been split on two lines on a thicker slip. There is a large part of the link that cannot be seen after the first line, but the end of the second line can be seen as well. Here the (fairly) readable parts are give, roughly in normal reading order.]
:a.org/wiki/Elsagate
:wiki/Bubbly_Creek
:wiki/Pheasant_Island
:a.org/wiki/American_death_triangle
:List_of_fictional_colors
:/wiki/Future_of_Earth#Introversion
:pedia.org/wiki/Fastest_animals#Invertebrates
:ki/Defence_Scheme_No._1
:i/Boeing_YAL-1
:ki/Bald-hairy
:/Walkalong_glider
:Burned_house_horizon
:/wiki/AVE Mizar
:Flying_ice_cube
:Time in Australia#Anomalies:
:Unexplained_sounds
:Talk:List_of_U.S._states_and_
:::::Ebright_Azimuth
:Mosquito_laser
:January_0
:/1808_mystery_eruption
:/Hairy_Hands
:Cumberland_vs._Georgia_Tech_football_game
:Timeline_of_the_far_future
:/wiki/1994_Caribbean_Cup#Anomaly

:[Caption below the panel:]
:I have a collection of Wikipedia links to throw behind my car if I'm ever being chased by someone as easily distracted as me.

{{comic discussion}}

[[Category:Wikipedia]]
[[Category:Comics featuring Cueball]]
[[Category:Comics featuring Hairy]]

1699: Local News

2021-03-30T14:29:54Z

Aid1043: /* Minor punctuation/grammar edit on the last paragraph. */

{{comic
| number = 1699
| date = June 27, 2016
| title = Local News
| image = local_news.png
| titletext = Will there ever be a physics term greater than 'tachyonic antitelephone?' According to this message from the future, the answer is 'no.'
}}

==Explanation==
Typical news broadcasts are divided into local, national, and global news segments. The broadcast in this comic presented by [[Blondie]], the [[:Category:News anchor|news anchor]], has been broken into real local, (about city council election) and what the newscaster calls "nonlocal". Rather than focusing on national or global news, the nonlocal segment deals with news of a {{w|nonlocality}} nature; more likely dealing with causal nonlocality.

A "{{w|tachyon}}" is a theoretical or thought-experiment particle which travels {{w|Faster-than-light|faster}} than the {{w|speed of light}}. It has many strange properties, including being able to go back in time. This is how the newscaster is able to send a beam back in time to kill her past self. The comic does not explain {{w|Grandfather paradox|the paradox}} of how someone who died in the past could still be alive in the present/future, nor any of the many other paradoxes that arise when {{w|time travel}} is involved, a [[:Category:Time travel|recurring theme]] in xkcd.

The title text asks if there could ever be a greater physics term than ''{{w|tachyonic antitelephone}}'', a theoretical device which would allow messages to be sent to the past. The text then continues to answer the question via a message from the future (presumably sent by antitelephone). The answer is ''No'' - there will never be a greater physics term.

==Transcript==
:[Blondie as a news anchor is sitting behind a table with her arms resting on the tabletop.]
:Blondie: In local news, city council elections were held today.
:Blondie: In nonlocal news, I killed my past self with a tachyon beam.

==Trivia==
*Blondie was finally named as a new character based on this comic. See the discussion below and this [[explain_xkcd:Community_portal/Proposals#New_character_category_for_blonde_woman_news_reporter_.28from_1699.29|community portal discussion]].
*And seeing she was often used as a news anchor that [[:Category:News anchor|new category]] was also based on this comic.

{{comic discussion}}
[[Category:Comics featuring Blondie]]
[[Category:News anchor]]
[[Category:Politics]]
[[Category:Physics]]
[[Category:Time travel]]

1659: Tire Swing

2021-03-23T12:20:21Z

Aid1043: /* Adjusted grammar in the penultimate paragraph. */

{{comic
| number = 1659
| date = March 23, 2016
| title = Tire Swing
| image = tire_swing.png
| titletext = If we find one of those tire dumps, the next time he tries to get his truck back we can just retreat and let him have it.
}}

==Explanation==
In this comic, [[Science Girl]] and another girl have just completed a {{w|tire swing}}, a common makeshift {{w|swing (seat)|swing}} is created by hanging a car {{w|tire}} from a length of rope, typically tied to the branch of a tree as in the comic. The other girl might at first look like she has hair like [[Megan]] but not quite as she is revealed upon zoom in to have curly hair. That they are rather small kids can be seen from the size of the tire compared to them. (They could be the same as the girls in the last panel of [[1580: Travel Ghost]]).

In the second panel of this comic Science Girl muses that there are huge tire dumps filled with nothing but old tires that have no use. In the last panel, Science Girl continues that maybe they should use a tire from such a dump next time they make a tire swing. The presumption is that perhaps they used a brand new tire, or a tire from some other source. This is confirmed by the other girl's response (and also by the title text, see below) which makes it clear that the tire they used was in fact stolen from a guy's vehicle. The last reply from Science Girl suggests the victim put up a fight and they had to take the tire by force. So these two small girls actually fought an adult man over his truck and won the fight.

Vehicle tires have a limited lifespan. The natural end of their life is when the pattern of raised treads on the circumference of the tire, which promote traction on wet roads, are worn down to a point where they are no longer effective enough, or after 6-10 years (sunlight causes the rubber to degrade, so the tire becomes prone to cracking and unsafe, even if it appears to be in good condition). Tires can also become damaged in other ways, such as puncture.

{{w|Tire recycling|Used tires}} are a notable ecological problem for a number of reasons (e.g. their size, the quantity produced, their relatively short lifespan, and the fact that they are difficult and slow to break down and contain a number of components that are ecologically problematic). A tire swing represents a functional use for otherwise useless old tires. The amount of tires (it is estimated that 259 million tires are discarded annually) makes them attractive targets for recycling. More than half of used tires are ultimately simply burned for their fuel value (which prevents them from sitting in landfills indefinitely, but this may even be worse as it releases otherwise locked up carbon thus releasing this into the atmosphere and making {{w|global warming}} even worse). Some steel mills that use electric arc furnaces will mix shredded tires with their scrap when charging the furnace for both the carbon value and fuel value, in place of the coal that would otherwise be used.

The comic is thus clearly [[Randall|Randall's]] attempt to draw attention to this huge ecological problem, as he so often before has done with other climate change/global warming related comics. (Climate change, especially global warming, is a [[:Category:Climate change|recurring theme]] in xkcd). So while this is not the joke of the comic, it could be the point of it.

He also suggests another way to use old tires. It should be noted that used tires are not necessarily safe to use as a kids' toy as they could become sharp/frayed along the edges and stones and other hard/sharp objects may have become stuck in the tires (even going all the way through), during its life span, or worn thin enough to tear apart mid-swing (when the stresses on the swing material would be at their peak). So tires bought for use as a swing may even be made from a new tire, but not necessarily of the same solid type as those used for cars. Used tires reused for a swing should be inspected for the problems mentioned above.

The title text goes further, suggesting that they actually stole the victim's entire truck - possibly just to harvest the tire needed for the swing - and that he unsuccessfully attempted to recover the truck, so they probably did fight him. He put up enough of a fight that they do not wish to fight him again (so he at least survived). Further, since the girls expect him to try again (maybe recovering the truck with only three tires), they apparently still have the truck. One of the girls suggests that if they could find one of these tire dumps, then they could take a tire from there, make a new swing, and then just walk or run away from the truck when the guy comes back, letting him have it if he really wants it so bad.

The reason Science Girl made this swing could be that she wishes to become a {{w|cosmologist}} as a reference back her meeting a cosmologist on a tire swing in [[1352: Cosmologist on a Tire Swing]].

Note that {{w|Calvin and Hobbes}}, which has often been [[:Category:Calvin and Hobbes|referenced in xkcd]], has done the same to Calvin's father as the girls did to the guy (though without the violence) in a [http://assets.amuniversal.com/bcb737d0b98e013340c2005056a9545d similar comic].

This was the first of two Wednesday's in a row where Randall used two children to make a reference to an environmental issue, the second being [[1662: Jack and Jill]] about {{w|hydraulic fracturing|fracking}} also with Science Girl.

==Transcript==
:[Science Girl and a girl with long curly hair, are standing under a large leafless tree as Science Girl adjusts a tire swing hanging from the largest of the branches of the tree. The tire hangs so high that the small girls only reach up to just above the center of the tire which has a diameter of more than half the height of the girls.]
:Science Girl: OK, looks good.

:[Zoom in on the girls so only the tire swing can be seen, and nothing of the tree. They both look at the tire.]
:Science Girl: I read that there are these huge dumps everywhere full of millions of old tires that no one knows what to do with.

:[Same setting but Science Girl looks up at the tree (outside the frame).]
:Science Girl: We should use one of those next time.
:Curly haired girl: Yeah. That guy was real mad.
:Science Girl: I would ''not'' want to fight him again.

{{comic discussion}}



[[Category:Comics featuring Science Girl]]
[[Category:Climate change]]

1590: The Source

2021-03-10T14:30:12Z

Aid1043: /* Removed an extra ")" */

{{comic
| number = 1590
| date = October 14, 2015
| title = The Source
| image = the_source.png
| titletext = Why did we even have that thing?
}}

==Explanation==
This comic is about experiencing a high pitched hum in an empty room. An "empty-room hum" is a high pitched buzzing noise, often caused by {{w|tinnitus}}, which is a medical condition causing high-pitched noise when there is no other noise around. Tinnitus is normally a hearing condition, not a disease. It may result from the brain [http://wiki.answers.com/Q/What_is_the_high_pitched_humming_sound_often_heard_in_an_otherwise_empty_and_silent_room increasing its sensitivity to noises.]

Sometimes not everyone can hear "empty-room hum"; however, those who can hear it usually find it immensely annoying. If you do hear the noise, you would like to locate '''The Source''' – hence the title of the comic. Hopefully when you find the source, you can do something about it. Or if you don't find it, you can at least be at ease knowing that others experience the empty-room hum, it having been referenced in two xkcd comics now and [http://wiki.answers.com/Q/What_is_the_high_pitched_humming_sound_often_heard_in_an_otherwise_empty_and_silent_room elsewhere] on the internet.

This comic alludes to the perspective of an outside observer who doesn't hear the hum but is watching someone who can hear it: because the sound isn't written out in text, the comic reader at first is confused by Cueball's inexplicable searching.

In the first two frames of the comic we see [[Cueball]] trying to locate the direction of the sound, by standing in the middle of the room, turning his head from one to the other side. Finally he walks down a flight of stairs (probably to the basement) and here he locates the source: A machine whose only function is to generate a high pitched hum. The title text asks why on Earth they had such a machine in the first place, which is somewhat difficult to explain and likely the crux of the title text's joke.

Luckily it was thus easy for Cueball to get rid of this sound at the source. But in real life most electronics generate hums and cannot reasonably be turned off without losing functionality. For instance fluorescent lights, phone chargers and computer modems are common culprits, refrigerators and washing machines less commonly. It could also come from outside the house, in which case it will be much harder either to locate the source or to do anything about it. Power lines and transformers are common outside sources.

There do, however, exist devices that are meant to create a high pitched hum, that people might wish to install in their house. These will be humming in the {{w|ultrasound|ultrasonic}} regions, although cheap versions can often be heard by young people. They are typically used for {{w|Electronic_pest_control#Ultrasonic|electronic pest control}}, while slightly lower frequencies which can typically be heard only by young people are sometimes used to {{w|The Mosquito|repel children}}. It is possible that someone tried to get rid of Cueball.

There do exist {{w|white noise}} generators (which make equal volume noise on every frequency) and {{w|pink noise}} generators (which make noise that sounds equally loud to the human ear at every frequency) which are used to test recording studios to see if they have good sound quality. It seems unlikely that the device is one of these, as it seems to be designed to generate a high-pitched hum: pink/white noises are categorically and perceptually different from a hum.

The sound wave spectrum in [[273: Electromagnetic Spectrum]] also contains a line for "that high-pitched noise in empty rooms".

The empty white room also could be a reference to a scene from [https://en.wikipedia.org/wiki/The_Matrix_Reloaded The Matrix Reloaded] in which Neo searches for "The Source," though this is likely just a coincidence.

There is a story by A.E. Van Vogt in "The War Against the Rull" where an all-pervasive vibration leads to a coming of age for the youthful protagonist.

==Transcript==
:[Cueball is standing in an empty room looking in the direction of the next frame.]

:[Cueball turns his head and looks the other way.]

:[Three smaller panels with the same total height as the first two frames follows. In the first frame Cueball walks on a grey surface.]

:[In the next Cueball is standing between two doors, looking over his shoulder towards the one to the left, but choosing the one to the right behind which a stair is. He is waking towards this door with his hand out towards the knob.]

:[In the last of these smaller panels Cueball has just walked down to the bottom of the stairs.]

:[Cueball walks towards a machine that is standing near a wall connected to a socket in the wall. On the machine it says:]
:High pitched hum generator

:[Cueball kneels behind the machine and unplugs it from the socket in the wall.]
:High pitched hum generator

:[Cueball walks away from the machine, the plug now lying on the floor between the wall and the machine.]
:High pitched hum generator

==Trivia==

'Empty room hum' is also referred to in [[273:_Electromagnetic_Spectrum#The comic in detail|other waves]] in [[273: Electromagnetic Spectrum]] and the title text in comic [[597: Addiction]].

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

Talk:1557: Ozymandias

2021-03-08T19:18:56Z

Aid1043:

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)

:: I thought everyone (American) knew the song (needs music notation) "There's a Hole in the Bottom of the Sea?" One version finally ends with "There's a germ on the flea on the hair on the speck on the spot on the wart on the frog on the bump on the log in the hole in the bottom of the sea." But kids make up all sorts of variations. Or they used to. [[User:Taibhse|Taibhse]] ([[User talk:Taibhse|talk]]) 10:00, 30 July 2015 (UTC)

: There's also [[Special:Contributions/108.162.215.30|108.162.215.30]] 20:28, 29 July 2015 (UTC)

:: Yon Yonson - https://en.wikipedia.org/wiki/Yon_Yonson
:: Mighty mighty - https://answers.yahoo.com/question/index?qid=20070602235838AA6qSzz {{unsigned ip|108.162.215.30}}

::
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)
: I think that might be the point actually, the idea is that with each time someone tells the poem to someone else, it grows by one, for each traveler from an antique land has been told by by a different traveler from an antique land[[Special:Contributions/108.162.219.39|108.162.219.39]] 01:08, 30 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)
:You have to read traveler as trav'ler. [[User:Uptonc|Uptonc]] ([[User talk:Uptonc|talk]]) 16:57, 29 July 2015 (UTC)
:: Well, that's just wrong... [[Special:Contributions/108.162.216.81|108.162.216.81]] 17:14, 29 July 2015 (UTC)
::: Um... No it's not. There are [http://dictionary.reference.com/browse/traveler?s=t two ways to pronounce it] (trav-uh-ler and trav-ler), kind of like toe-may-toe, toe-mah-toe. [[Special:Contributions/108.162.219.196|108.162.219.196]] 18:11, 29 July 2015 (UTC)
::::And you can pronounce "dog" as "cat". Language is funny like that. [[Special:Contributions/108.162.210.187|108.162.210.187]] 15:24, 30 July 2015 (UTC)
:::::Ok it's going to bug me otherwise, but, how? I mean, I figure it's probably one of those ghoti-fish things, but still. -Pennpenn
::::::Sorry it took so long to see your response and to respond to it. I meant that the symbols that make up "dog" are arbitrary, and could just as easily be pronounced as anything. Language itself is arbitrary and new words are made all the time, and pronunciations of old words are changing as well. Rules of grammar change constantly, to the ire of English teachers everywhere. [[Special:Contributions/108.162.210.205|108.162.210.205]] 19:18, 26 September 2015 (UTC)
[[Special:Contributions/108.162.250.162|108.162.250.162]] 23:07, 30 July 2015 (UTC)
::::::There's certain British accents (and probably elsewhere, but let's start here as an example) where a person saying a word such as "film" can only seem to say it as if it is "fillum". A kind-of-1.5-syllable-at-most word for most people (close to the word "firm", but the tongue used differently), but distinctly two for others (who ''can'' say their "L"s, but 'disengage', rather than let the word flow). (Actually, there's also accents that would make "firm" sound like "firrum", because of their 'harder' "R"s, but that's superfluous to this explanation.) So if you have a problem getting "Traveller" down to the two-syllable "Travler", you may have a similar sort of acquired pronunciation. See also "vehicle" ("vee-hic-al", "vere-cal"), which I know is predominant in certain of the US states. [[Special:Contributions/141.101.98.188|141.101.98.188]] 06:14, 1 August 2015 (UTC)

I think everyone's looking far too hard for something obscure and clever. :) Ozymandias is in the poem described as the "king of kings", which makes him recursively kingly. Hence, the recursion joke. (I went ahead added that to the explanation, it's my first contribution here so hopefully I didn't bypass any explainxkcd wiki house rules) [[User:Orinthe|Orinthe]] ([[User talk:Orinthe|talk]]) 06:24, 30 July 2015 (UTC)

When my brother and I were very young, and stayed overnight at my grandparents, my grandfather would often tell us the following bedtime story, with great seriousness, and many dramatic pauses:

"We were all seated around the camp fire, when the Captain said, to his faithful servant: 'Antonio, Antonio, tell unto us a story.' And Antonio began: "We were all seated around the camp fire, when the Captain said, to his faithful servant: 'Antonio, Antonio, tell unto us a story.' And Antonio began: "We were all seated around the camp fire, when the Captain said, to his faithful servant: 'Antonio, Antonio, tell unto us a story...

By that time we were often asleep. {{unsigned|Matthew-e-hackman}}

There is a old Chinese story with recursion like this that goes like:
<pre>从前有座山 Once upon a time, there was a mountain.
山上有座庙 Upon that mountain, there was a temple.
庙里有个老和尚和小和尚 In the temple was an old monk and a young monk
老和尚讲了一个故事说 The old monk told a story, saying
从前有座山 Once upon a time, there was a mountain.
山上有座庙 Upon that mountain, there was a temple.
庙里有个老和尚和小和尚 In the temple was an old monk and a young monk
老和尚讲了一个故事说 The old monk told a story, saying
....</pre>

[[Special:Contributions/162.158.255.59|162.158.255.59]] 07:00, 31 July 2015 (UTC)

Not that you need another example of recursion, but this brings back very distinct personal memories. Whilst my father actually used to read books to me, at bedtimes, on occasion (for whatever unfathomable reason, lost on the mists of time) he would sometimes tell me a freestyle story that started "Once upon a time, there was a little boy who said to his daddy 'Daddy, tell me a story!', and his daddy said, alright then. 'Once upon a time, there was a little boy who said to his daddy "Daddy, tell me a story!", and his daddy said, alright then. "Once upon a time, there was a little boy who said to his daddy 'Daddy, tell me a story!', and his daddy said, alright then. ..."'" But by that point (if not earlier, depending on how grumpy I was) I'd usually interupt him, so I suppose I never actually ''did'' find out what where this was might have been going. (And he forever asserted it ''was'' going somewhere.) [[Special:Contributions/141.101.98.188|141.101.98.188]] 06:14, 1 August 2015 (UTC)

This comic's TOO META. [[Special:Contributions/108.162.210.135|108.162.210.135]] 21:23, 2 August 2015 (UTC)

In response to "You're/That's/This is crazy: "Crazy!? I was crazy once. They took me to a room and locked me up. There were rats in that room that gnawed at the walls. The rats drove me crazy! Crazy!? I was crazy once ... " and so on...[[Special:Contributions/108.162.221.91|108.162.221.91]] 20:40, 1 September 2015 (UTC) Kickasstimus

The B in "Benoit B Mandelbrot" stands for "Benoit B Mandelbrot."
Also I think Randall got the idea from this SMBC:
http://www.smbc-comics.com/?id=2470
Which is incidentally based off of the aforementioned joke.
[[User:International Space Station|International Space Station]] ([[User talk:International Space Station|talk]]) 04:58, 7 October 2015 (UTC)

Not quite sure what the proper protocol is, but it feels like the comment/suggestion at the end of the first paragraph should be in this discussion box rather than making the article itself more confusing to read.
--[[User:Aid1043|Aid1043]] ([[User talk:Aid1043|talk]]) 19:18, 8 March 2021 (UTC)

1551: Pluto

2021-03-08T19:12:22Z

Aid1043: /* In the final paragraph of the Explanation, the sentence that begins "There actually exist the terms Plutoid and Plutino..." was repeated twice. The first instance was removed. */

{{comic
| number = 1551
| date = July 14, 2015
| title = Pluto
| image = pluto.png
| titletext = After decades of increasingly confused arguing, Pluto is reclassified as a "dwarf Pluto."
}}
When the image is clicked the corresponding [http://www.nasa.gov/feature/new-horizons-spacecraft-displays-pluto-s-big-heart-0 NASA post] opens up.
==Explanation==

This comic was posted on Tuesday, July 14, 2015, in honor of the {{w|New Horizons}} deep space probe making its flyby at {{w|Pluto}}, thus breaking the typical Monday/Wednesday/Friday cycle for the [[xkcd]] comics. Also on this day he released the first [[what if?]] in over three months, and it was called [http://what-if.xkcd.com/137/ New Horizons]. Luckily it did not end up back on Earth, as depicted in [[1532: New Horizons]], released 1½ month before closest approach.

[[Randall]] has taken one of the probe's images of Pluto, and outlined humorous examples of {{w|Pareidolia|pareidolia}} on top of it.

It can be compared to preliminary descriptions by geologists, e.g. [http://www.planetary.org/blogs/emily-lakdawalla/2015/07140911-new-horizons-best-look-at.html?referrer=http://t.co/ExQJ6cKS1Q New Horizons' best look at Pluto before close approach|The Planetary Society].

The comic probably wink at {{w|Percival Lowell}} whose observatory photographed Pluto in 1915 "known" as Planet X. Unfortunately Percival Lowell is most famous for his drawings of the {{w|Martian canal|Canals on Mars}} which are widely misunderstood as channels based on wrong translations from Italian to other languages.

The title text refers to the debate as to whether Pluto should be classified as a full or dwarf planet. This debate was particularly brought into the public eye and came to be seen as a matter of controversy, following the 2006 {{w|IAU definition of planet}}. The text may imagine that this debate winds on, with definitions being created and revised until a ridiculous state is reached whereby Pluto has a special class of celestial body named after it called a 'Pluto' but fails to fulfill the arbitrary criteria set up for it, and hence is called a 'dwarf Pluto'. There actually exist the terms {{w|Plutoid}} and {{w|Plutino}}, that relate directly to groups that Pluto belongs to, but see those pages for details of their use and usage. There has been a real naming conflict whilst generating those two categories, where Plutons was the name chosen initially, whereas Pluton is the usual name of Pluto in some languages.

===Details on Randall's discoveries===

;Candy shell
Suggests Pluto is a confection, like [http://wiki.kerbalspaceprogram.com/wiki/Minmus Minmus]. May also be a reference to the [https://en.wikipedia.org/wiki/Mars_%28chocolate_bar%29 Mars] candy bar.

;JPEG plumes
The {{w|JPEG}} image format has the common issue of slightly distorting an image with {{w|Compression artifact}}s. The artifacts shown here do not appear in the official version of this image, but all data sent from New Horizons is compressed and artifacts are common — the full resolution images will be submitted to earth over the next 16 months. There have been tweets about people seeing plumes associated with active volcanoes and the like, which were explained as being artifacts.

;Frontal bone
Interpreting Pluto as a head, the {{w|frontal bone}} could be the light-colored region next to the darker top, just above the north pole facing to us.

;Grease stains
The area above Pluto's north pole is attributed to grease.

;Bugs
Could refer to possible extraterrestrial life on Pluto in the form of {{w|insects}}, or "bugs". In the animated TV series ''Roughnecks: Starship Troopers Chronicles'', an adaptation of Robert Heinlein's novel ''Starship Troopers'', the first battles with the alien "Bugs" took place on Pluto. Maybe it also refers to a software bug at the probe.

;Bullet holes
A string of small round features which Randall suggests was the result of Pluto getting shot repeatedly, probably by meteorites.

;New Netherlands
Reference to the what if?, [https://what-if.xkcd.com/54/ Drain the Oceans: Part II], about draining the Earth's oceans onto Mars. In the previous what if?, [https://what-if.xkcd.com/53/ Drain the Oceans], the Netherlands took over the Earth once their problem with the risk of flooding disappeared. And then they continued to issue forth from the portal that drained the oceans on Earth pouring them onto Mars, to claim Mars as New Netherlands. Presumably, something similar happened on Pluto. This was already again references in both an entry in the table and in the title text of [[1555: Exoplanet Names 2]].

;Disputed territory
Since the base photograph is identified as "today's ''New Horizons'' image," this indicates that a section of Pluto has immediately become the subject of some controversy, possibly a territorial claim or one of several references to the fact that Pluto was demoted from full planet status in 2006.

;Snake pit
A generic map hazard.

;{{w|Pareidolia|Full text of the Wikipedia article on pareidolia}}
Pareidolia is the human brain's tendency to see patterns where they don't exist. While probably a reference to Pluto's heart, the joke is also recursive: You'd be seeing the text of a Wikipedia article explaining to you that you couldn't actually be seeing the text of a Wikipedia article.

;Tadpole
One of a number of pareidolic features Randall has outlined.

;Kuiper Belt loops
The {{w|Kuiper belt}} is a region in our solar system that contains an unknown amount of icy bodies, one known is Pluto. Randall jokingly refers to Kuiper Belt as the same kind of belt that's used to fasten clothing and identifies features on Pluto's surface as loops for the belt.

;Serenity
An outline of the ''Firefly''-class spaceship ''Serenity'', which was the titular vessel from the 2002 TV series ''{{w|Firefly (TV series)|Firefly}}''. One of a number of pareidolic features Randall has outlined.

;Dinosaur
Nobody can see a dinosaur unless Randall did do this painting on Pluto's surface. And a complex comic needs at least one dinosaur.

;The good part
A section of Pluto that is objectively better than the rest.

;Moon bud
This could be interpreted as a moon growing/emerging out of Pluto, as a bud is "a compact knob-like growth". A round growth is seen at the location marked, resembling a small, emerging moon.

;Ghost
A reference to the classic video game ''{{w|Pacman}}'', wherein the primary antagonists are one of four Ghosts. The Ghost on Pluto appears to have a mouth, however, unlike most depictions of the ''Pacman'' Ghosts. One of a number of pareidolic features Randall has outlined.

;Pluto dinosaur extinction crater
Suggests Pluto had dinosaurs and lost them the same way Earth did.

;{{w|The Heart (Pluto)|Heart}}
One of a number of pareidolic features Randall has outlined, and the only one (currently) also informally named as such by NASA.

;Coronary artery disease
Also known as {{w|ischemic heart disease}}, which causes degradation of heart tissue. The region identified in the comic looks less 'healthy' (is darker and more ragged) compared to the rest of the 'Heart', which Randall suggests is caused by the disease.

;Mount Mons
Referring to the general practice of naming extraterrestrial mountains {{w|Mons (planetary nomenclature)|"X Mons"}} (e.g. {{w|Olympus Mons}}, a mountain on Mars and the largest mountain in the Solar System), as well as naming terrestrial mountains "Mount X". Since "mons" is Latin for "mountain", the feature's suggested name translates as "Mount Mountain".

;Charging socket
A terrain feature suitable for connecting an outside source of electricity for the benefit of implied internal batteries. Compare "dock connector," below.

;Cracks (beginning to hatch)
Implying that Pluto is some manner of a giant egg. Possibly a reference to the ''Doctor Who'' episode ''Kill the Moon'', in which the Moon is revealed to be an egg from which a monster is hatching. A 2014 article from ''The Onion'', [http://www.theonion.com/article/moon-finally-hatches-36414 "Moon Finally Hatches,"] makes the same joke. Also possibly a reference to ''The Light Fantastic'', a ''Discworld'' novel in which similar objects are revealed to be the eggs of the world turtle. A similar idea appeared in Jack Williamson's 1934 short story "Born of the Sun".

;Plug (inflating/deflating)
Inflatable balls often have a "plug" or opening to insert a needle to inflate or deflate them.

;Scars from predator attacks
Since it's all-caps, we can't tell if "PREDATOR" is a proper noun, but this is possibly a reference to the movie series ''{{w|Predator (franchise)|Predator}}'', about a race of aliens who hunt other beings for sport. Alternatively, a planetary predator (such as comic book villain {{w|Galactus}}) may have previously scarred Pluto.

;Reset button
The structure indicated is a small black dot (at least at this distance this picture was taken). Reset buttons on home electronics are often small buttons or holes used to reset the software of the electronic device.

;Megaman
One of a number of pareidolic features Randall has outlined, this one in the shape of a {{w|Mega_Man_(character)|popular video game protagonist.}}

;Debate Hole - Where we're putting all the people still arguing about Pluto's planet status
Pluto was reclassified as a {{w|dwarf planet}} rather than a {{w|planet}} following the latter term's controversial {{w|IAU definition of planet|redefinition in 2006 by the International Astronomical Union}}. Arguments about the classification continue to pop up. The same argument is referenced in the title text. The name implies a proposal to put all the people still arguing about it in this hole on Pluto. This proposal further implies that the continued debate is very annoying by 2015, except perhaps to the debaters themselves.

;Area missed during ironing
The area indicated is near the {{w|Terminator (solar)|terminator}} and shows some intriguing topographic relief.

;Probably Benign
A {{w|neoplasm}} or tumor is an abnormal growth of tissue. Randall is suggesting that the abnormal region near the heart has been evaluated by a doctor and determined to be {{w|Benign tumor|benign}}.

;Chocolate frosting
Suggests the discrepancy in color over Pluto's surface may be a function of what cake frosting was used where. This area is the "dark spot" at the head of the "whale" (http://www.nytimes.com/interactive/2015/07/14/science/space/pluto-flyby.html). The so-called "whale's tail" (http://www.nbcnews.com/science/space/find-heart-whale-new-horizons-picture-pluto-n388816), is on the other hemisphere and is not visible in this image, it lies east about 90 degrees from the chocolate frosting/dark spot here.

;Vanilla frosting
As above, suggests the discrepancy in color over Pluto's surface may be a function of what cake frosting was used where.

;Border of pride lands
A reference to the Disney animated feature ''The Lion King.'' In the movie, the Pridelands is the bright and prosperous region ruled by the Lion King while a dark territory beyond its border is controlled by hyenas.

;Hyena country
A continuation of the ''Lion King'' reference above.

;Dock connector
From the point of view of the photograph, this feature of Pluto is at the planet's "bottom," where iPod dock connectors are. Compare "charging socket," above.

==Transcript==
:'''PLUTO'''
:Some of the features already identified in today's ''New Horizons'' image

:[Many marks on the image of Pluto follow:]

:Candy shell
:Frontal bone
:Grease stains
:Bugs
:JPEG plumes
:Full text of the wikipedia article on pareidolia
:Bullet holes
:New Netherlands
:Disputed territory
:Snake pit
:Tadpole
:Pluto dinosaur extinction crater
:Kuiper beltloops
:Serenity
:Ghost
:Dinosaur
:The good part
:Moon bud
:Scars from predator attacks
:Reset button
:Megaman
:Charging socket
:Cracks (beginning to hatch)
:Plug (inflating/deflating)
:Heart
::Mount Mons
::Coronary artery disease
:Debate hole
::Where we're putting all the people still arguing about Pluto's planet status
:Chocolate frosting
:Probably benign
:Vanilla frosting
:Dock connector
:Border of pride lands
:Hyena country
:Area missed during ironing

:Image credit: NASA/JHUAPL/SwRI - click for original

{{comic discussion}}

[[Category:Comics with color]]
[[Category:Space probes]]
[[Category:Astronomy]]
[[Category:Firefly]]
[[Category:Food]]
[[Category:Dinosaurs]]
[[Category:Wikipedia ]]
[[Category:The Lion King]]