explain xkcd - User contributions [en]

Talk:3103: Exoplanet System

2025-12-02T17:45:28Z

82.132.237.203:

"Faint dust cloud that will cause several papers to be retracted" could refer to either Fomalhaut b (former proposed exoplanet that turned out to be a dust cloud) or Tabby's Star (star with odd irregular dimming pattern likely due to a dust cloud, but was briefly thought by some to be an alien megastructure the speculation of which caused the media to lose their shit). [[User:Erika lovelace|Erika lovelace]] ([[User talk:Erika lovelace|talk]]) 19:53, 16 June 2025 (UTC)

Somebody should word it better but the idea of a black hole accretion disk having a habitable zone is pretty typical for Randall brand humor. [[Special:Contributions/130.76.187.35|130.76.187.35]] 20:12, 16 June 2025 (UTC)
:I think it's actually a reference to [[wikipedia:Interstellar (film)|''Interstellar'']]. In that movie three planets are sort of in the habitable zone of a giant black hole's accretion disk. Whether that means they have to be in the accretion disk, or whether they can be outside it but still in the habitable zone of the disk's radiation, I'm not sure. -- [[User:Ken g6|Ken g6]] ([[User talk:Ken g6|talk]]) 00:17, 17 June 2025 (UTC)
:An alternative reading of #18 is that the planet may or may not be too hot for rocks to solidify at the surface. (Even if this turns out to be implausible, Randall does stretch the bounds of plausibility on occasion.) [[Special:Contributions/87.75.45.216|87.75.45.216]] 08:36, 17 June 2025 (UTC)
:An accretion disk is also found around a star. So the exoplanet may be in the zone where planets may actually form. (talking about the title text) [[Special:Contributions/129.27.217.99|129.27.217.99]] 08:59, 17 June 2025 (UTC)
:: An accretion disk forms around my desk. Whether or not it counts as habitable is debatable, though. [[Special:Contributions/82.13.184.33|82.13.184.33]] 09:15, 17 June 2025 (UTC)
:Yeah, the Earth is thought to have formed from the accretion disk of the Sun 4.5b years ago. It probably has nothing to do with black holes. [[User:Robisodd|Robisodd]] ([[User talk:Robisodd|talk]]) 12:12, 17 June 2025 (UTC)
::This is my reading of it too: the planet being within the habitable zone of the accretion disk is (IMO) referencing a very young solar system, discovered at some time before the planets have swept their orbits clear. Therefore although "habitable", it'll be a few hundred million years before even what we hypothesize as the "Late Heavy Bombardment", concomitant with the very earliest traces of life on Earth. In other words, great news for future colonization as long as your hopes for the future are not contingent on there being anyone remotely human still around... [[Special:Contributions/2A01:CB08:E6:7000:910F:2296:2C6D:46C4|2A01:CB08:E6:7000:910F:2296:2C6D:46C4]] 10:27, 18 June 2025 (UTC)
:My read of this is that the planet is habitable but perhaps it "doesn't like" life. [[User:Galeindfal|Galeindfal]] ([[User talk:Galeindfal|talk]]) 13:36, 17 June 2025 (UTC)
:Weird side note: isn't Anne McCaffrey's PERN technically a Habitable planet that passes trough an accretion disk? There's a whole subplot about doing some weird magic-science to stabilize the orbit and stop the inspiraling in the later books. [[Special:Contributions/104.129.192.49|104.129.192.49]] 22:33, 17 June 2025 (UTC)

I'm a little unsure of this so could someone help me confirm my theory? There is a shape in xkcd: Escape Speed that looks quite similar to the "faint dust cloud that will cause several papers to be retracted" shape (in xkcd: Exoplanet System). I'm wondering if xkcd: Exoplanet System might be a map of the xkcd: Escape Speed world? [[User:RedDragon|RedDragon]] ([[User talk:RedDragon|talk]]) 14:53, 17 June 2025 (UTC)RedDragon

I assumed the "fist-sized rock" was something relatively close to the observatory, which is not calibrated properly so it seems to be at the star's distance. [[User:Barmar|Barmar]] ([[User talk:Barmar|talk]]) 16:09, 17 June 2025 (UTC)
:https://www.youtube.com/watch?v=MMiKyfd6hA0 [[Special:Contributions/92.23.2.228|92.23.2.228]] 20:17, 17 June 2025 (UTC)

Could the ‘fist-sized rock’ be a reference to Welcome To Night Vale, in which a character, named Sarah Sultan is a ‘fist-sized river rock’? [[User:Broseph|Broseph]] ([[User talk:Broseph|talk]]) 06:18, 18 June 2025 (UTC)

The intro seems to major a little too heavily on the habitability aspect. Only four of the items in the comic mention habitability - five if you count the 'Earth-like data artifact' - plus the title text. That's not even a third of the total items. Astronomers aren't only interested by worlds that might be habitable - they're excited by the vast array of interesting things out there. [[Special:Contributions/82.13.184.33|82.13.184.33]] 08:31, 18 June 2025 (UTC)

"Wet Saturn" and "Hot Mars" may also be a reference to Pliny the Elder's Historia Naturalis, Book 2 Chapter 18. https://www.perseus.tufts.edu/hopper/text?doc=Perseus%3Atext%3A1999.02.0137%3Abook%3D2%3Achapter%3D18

im sorry is this website using biased odds for random comics?? because i’ve got a comic in the last 200 published at least 20 times out of the last 25 i’ve rolled. and 2 of the others were the same non comic [[Special:Contributions/92.40.197.124|92.40.197.124]] 17:11, 2 December 2025 (UTC)
:Unfortunately, [[explain xkcd:Community portal/Miscellaneous#Random Explanation Button bias towards newer articles|yes]], and people have discovered that it's a wiki thing, not specifically anything to do how this site uses its Random button. Though it has been changed to include the set of non-comic page-explanations, as well as numbered/non-numbered comics, which is a fairly new (and deliberate) development. [[Special:Contributions/82.132.237.203|82.132.237.203]] 17:45, 2 December 2025 (UTC)

Talk:893: 65 Years

2025-12-02T17:29:38Z

82.132.237.203:

I wonder if it would be possible to identify ''individual people'' who are behind those vertical jumps in the graph (in the not projected part)... --[[User:JakubNarebski|JakubNarebski]] ([[User talk:JakubNarebski|talk]]) 19:18, 14 December 2012 (UTC)
*Glad you asked! </Information Hen> Neil Armstrong and Buzz Aldrin landed in July 1969; that's two. Pete Conrad and Alan Bean joined the group that November; that's four. Alan Shepard and Edgar Mitchell in February '71; that's six. David Scott and James Irwin in July '71; that's eight. John W. Young and Charles Duke in April '72; that's ten. Eugene Cernan and Harrison Schmitt in December '72; that's twelve. Irwin died in '91, dropping it to 11. Shepard and Conrad died in '98 and '99 respectively, making it 9 as of the date this comic was published. Armstrong died in '12, so our current number is 8. The oldest living person to have landed on the moon is Aldrin, 83. There are two 82-year-olds, two 80s, one 78 and two 77s. [[User:Ekedolphin|Ekedolphin]] ([[User talk:Ekedolphin|talk]]) 13:28, 27 January 2013 (UTC)

Almost prophetic and very, very sad. RIP Neil Armstrong ------ {{unsigned ip|188.29.119.251|08:59, 31 December 2012 (UTC)}}

Can we add the 5% and 95% columns to the table? [[User:Spongebog|Spongebog]] ([[User talk:Spongebog|talk]])
::i dont feel like this would add to the explanation of the comic and would require us to know a great deal about the author's calculations. rather than attempt to redo the actuarial calculations performed to make the chart and assign this to the individuals in the table we should rather explain the concepts behind the 5% and 95% and preserve the intention of actuarial information as applying to demographic groups. 5% of people in the demographic the author selected live to _ age 95% of those people live to _ age and how this affects our subject population. [[User:Mrarch|Mrarch]] ([[User talk:Mrarch|talk]]) 21:43, 6 December 2013 (UTC)

Why is this explanation incomplete? The second paragraph does a good job explaining what the 5th percentile and 95th percentile are referring to. [[User:String userName = new String();|String userName = new String();]] ([[User talk:String userName = new String();|talk]]) 23:35, 19 June 2015 (UTC)

I prefer to think of the inhabitable planets as extensions to earth reserved for when we have learned not to kill all the inhabitants of the only inhabited planet in the universe. [[User:Weatherlawyer| I used Google News BEFORE it was clickbait]] ([[User talk:Weatherlawyer|talk]]) 22:39, 23 January 2015 (UTC)

I see no reason this is marked as incomplete; I've tidied up the percentile explanations, but haven't really added much more. I think it's fine, and will remove the incomplete tag in a few days if nobody objects. [[User:Cosmogoblin|Cosmogoblin]] ([[User talk:Cosmogoblin|talk]]) 13:53, 24 June 2015 (UTC)

'''UPDATED GRAPH:''' I've updated the image with a red line showing actual moon walker deaths. View here: [https://i.imgur.com/G7DbbBi.png]. Sadly, it's right on track. [[Special:Contributions/172.68.58.59|172.68.58.59]] 22:19, 9 August 2018 (UTC)

As of mid April, 2020, this prediction is still accurate, but I'm really scared of what it'll be by the end of 2020 or 2021. Stay healthy everyone, astronaut or not! [[User:PotatoGod|PotatoGod]] ([[User talk:PotatoGod|talk]]) 07:04, 22 April 2020 (UTC)

Interesting that 6/12 of all the people who walked on the moon were born in 1930, and all bar Alan Shepard was born 1930-1935. Reminds me of some of the ideas in Malcolm Gladwell's *Outliers* about there being especially good birth years to succeed at high levels in given fields. It seems you want to have been mid-30s to early-40s (Shephard the outlier at 47) in the late 60s/early 70s. This also makes the comic more dramatic - if there had been a wider spread of ages, then the "death curve" would be a lot more gradual. -[[User:Honeypuppy|Honeypuppy]] ([[User talk:Honeypuppy|talk]]) 01:15, 30 September 2020 (UTC)
What? No. That's a false correlation. The moon program took place over a very short span of time, and was looking for very specific qualification. Including age.

Honorary mention: Michael Collins (1930-2021), RIP this date. [[Special:Contributions/162.158.158.104|162.158.158.104]] 17:44, 28 April 2021 (UTC)
:Also Thomas Stafford (1930-2024). [[Special:Contributions/172.71.242.5|172.71.242.5]] 17:10, 19 March 2024 (UTC)
IMO the saddest part isn't astronauts dying - it's lack of any new people getting to walk on another planet. [[Special:Contributions/162.158.90.157|162.158.90.157]] 14:04, 5 October 2021 (UTC)
:Well, if the {{w|Artemis program|Artemis missions}} go as planned, the count might soon be increasing again for the first time in fifty-three years. Hopefully, not all of the remaining veteran astronauts will have died by then. --[[Special:Contributions/162.158.22.16|162.158.22.16]] 22:57, 4 August 2023 (UTC)
::But with increasing delays (now until 2026) the window of time is closing. [[Special:Contributions/172.71.242.43|172.71.242.43]] 17:03, 19 March 2024 (UTC)

Shouldn't we count also the people that traveled around the Moon? {{unsigned ip|140.141.134.242|15:50, 2 December 2025 (UTC)}}
:We might, but the graph specifically is people who have ''walked'' on the Moon (or indeed any ''other'' 'other world'), so that's a different count. [[Special:Contributions/82.132.237.203|82.132.237.203]] 17:29, 2 December 2025 (UTC)

3173: Satellite Imagery

2025-12-02T17:23:07Z

82.132.237.203: /* Explanation */ There's no reason to believe this is (supposed to be) the stitched-together Google Maps. For the kind of intelligence-gathering these seem to be involved in, you work around (or despite) any unavoidable cloud-cover in the view.

{{comic
| number = 3173
| date = November 26, 2025
| title = Satellite Imagery
| image = satellite_imagery_2x.png
| imagesize = 429x526px
| noexpand = true
| titletext = Every weekend I take an ATV out into the desert and spend a day tracing a faint "(C) GOOGLE 2009" watermark across the landscape.
}}

==Explanation==
{{incomplete|This page's explanation has been obscured, and we're currently trying to figure out what it says. Don't remove this notice too soon.}}
This comic is another entry in the "[[:Category:My_Hobby|My Hobby]]" series of comics, and the first entry into the series since mid-2023.

[[Cueball]] and [[Ponytail]] are intelligence analysts, scrutinizing a projected image of an apparent satellite (or aerial) photograph. It features a parched landscape, of indeterminate scale, though has some clear watercourses flowing through it that suggest a fairly wide river and tributary, plus thin tracks that must be dirt roads serving various small buildings or compounds (depending upon the true zoom level) rather than game-trails.

In the middle of the image, spanning the river banks around a small bend, the image ''appears'' to have been pixelated, at least to the two characters viewing it.

They express concern that they're relying upon censored resources. Their commentary indicates that they are perhaps working for an intelligence agency working with classified imagery, who would expect to be using raw imagery, not something obscured. They're first considering whether they'd been provided the 'public'-level classification prepared by the satellite operator. Alternatively, they have stumbled upon a location that higher levels of their own agency (or partner domestic organisations) deem of greater security than they are entitled access to. The most frightening thought, though, is that a foreign counter-intelligence agency is protecting their own national secrets by hacking into their image-feeds and rendering them functionally useless.

To add to the confusion, the chosen location does not appear to have ''any'' relevant information recorded for it, such as whether it should contain a military base (of their own or their allies'; or of a potential/actual adversary). The lack of any other information, in the light of clearly hidden details, leads to a non-justifiable level of paranoia and concern over what might be being obscured.

As the caption reveals, the ''only'' pertinent things in that physical location are some very large squares, given various flat hues closely matching the original average ground appearance, entirely intended to be misinterpreted as post-process image pixelization. Since the combined structures stretch across several implied features (the width of the river and significant quantity of its bank, with possible buildings served by one of the dirt-tracks). Since this is another one of [[Randall]]'s hobbies, he most have done this a number of times, on the off-chance that someone will make the indicated assumptions.

Randall's deception could be exposed by sufficiently detailed clouds floating above the colored panels. If the tactical image was really pixelated, the clouds would appear pixelated too. Not to mention if the photography was not perfectly aligned with his own squares, even after rotation to more conventionally align with the usual modern {{w|Map#Orientation|'grid north'}} orientation.

In the title text, he continues to further confuse the remote-sensing people by drawing a {{w|watermark}} in the sand, leading people to believe the picture was taken in 2009 and is part of Google's publicly released material. Which, though it is indeed a possible source for the general public, could be unexpected in more serious and separately sourced ground imagery directly taken for more commercial, governmental or intelligence-agency purposes. Also if this is supposed to be either live images or those just taken today, and then if they have an old watermark from 2009 it seems like someone is feeding them old images, rather than the expected newer ones. This would be very concerning. And also make them wonder how those that could hack their system would be so remiss as to use watermarked and clearly dated images.

==Transcript==
:[Cueball and Ponytail are standing on either side of a board on a wall, which is displaying a satellite image of an area without cities. A large river is going through the left part of the image, going from north to south. Another river joins it from the left in the lower part of the image. A lake is in the right upper part of the image. There are a few white lines running through the image, probably roads. However, in the left part of the image over the middle of the north/south going river there is a square area which looks pixelated into 36 equal sized smaller squares. The color of the image is brownish with white and black and gray scales as well. The 36 smaller squares are held in these colors, though not white or black, but each small square is held in a uniform color, where the rest of the landscape has a smooth transition in colors from one place to the next.]

:Cueball: Wait, when was this imagery taken? Is this censorship the work of the contractor? One of our people? '''''Foreign actors!?'''''
:Ponytail: Do we know who's operating a facility at that location?
:Cueball: We can't find '''''anything'''''.

:[Caption below the panel:]
:My hobby: Setting up big colored panels in the middle of nowhere as a prank on remote sensing people.

{{comic discussion}}<noinclude>

[[Category:My Hobby]]
[[Category:Comics with color]]
[[Category:Comics featuring Cueball]]
[[Category:Comics featuring Ponytail]]
[[Category:Conspiracy theory]]
</noinclude>

Talk:3175: Website Task Flowchart

2025-12-02T16:25:54Z

82.132.237.203:

> who are available to produce words at you 24/7!

Is "produce words at you" an AI reference? -- [[User:Dtgriscom|Dtgriscom]] ([[User talk:Dtgriscom|talk]]) 19:40, 1 December 2025 (UTC)
:I think it is likely an AI reference. —[[User:Theusaf|theusaf]] ([[User talk:Theusaf|talk]]) 19:46, 1 December 2025 (UTC)
:I tend to agree, but it does say "live agents" earlier so it could also be a reference to live but non-native language speakers in a foreign call center. [[Special:Contributions/47.248.235.170|47.248.235.170]] 20:24, 1 December 2025 (UTC)Pat
::Real-time bots are live but not ''alive''. [[Special:Contributions/64.114.211.79|64.114.211.79]] 21:26, 1 December 2025 (UTC)
:::I feel like for some certain definition of 'alive' bots could be considered alive. They are (kind of?)sentient, which just means they can think. 'sapient', on the other hand, means that he/she/they is self-aware. While it is generally considered that bots are not live, this may not always be true. Depending on how advanced AI ever get, (most probable answer: not very) they may one day be able to evolve and reproduce. They already perform metabolism and homeostasis (power and fans). They have structure, they are made of computer chips (im not a computer nerd, so this probably isn't accurate). They react to stimuli. Honestly, all that needs to let them be considered 'alive' is for them to be able to make other AI and for those AI to be slightly different, which they kind of already can. Besides being made of metal, there is no real reason to claim that an AI isn't 'alive', that's just what mainstream media claims. --[[User:Kirinhatchi|Kirinhatchi]] ([[User talk:Kirinhatchi|talk]]) 01:05, 2 December 2025 (UTC)
:::They're certainly live as in "live TV" and/or a "live electricity socket", as in active/functional/doing-what-they-are-designed-to-do. [[Special:Contributions/78.144.255.82|78.144.255.82]] 01:44, 2 December 2025 (UTC)

wow second commenter --[[User:LazyTiger0203|LazyTiger0203]] ([[User talk:LazyTiger0203|talk]]) 19:45, 1 December 2025 (UTC)

Is Randall just now finding out about this?!? What sequestered Internet space has he been hiding in? I want. Of course it's probably gone now. [[Special:Contributions/205.175.118.2|205.175.118.2]] 20:20, 1 December 2025 (UTC)

I have fixed several spelling errors. [[User:RadiantRainwing|RadiantRainwing]] ([[User talk:RadiantRainwing|talk]]) 02:49, 2 December 2025 (UTC)

I would replace the "Throw electronics into sea" step with "As soon as the call is no longer on hold, say the website the hold message suggests ''is not working''". Throwing devices into sea causes e-waste. [[Special:Contributions/2001:4C4E:1C14:9800:F167:89F7:6CCE:353B|2001:4C4E:1C14:9800:F167:89F7:6CCE:353B]] 08:30, 2 December 2025 (UTC)
:Who cares about that, when the big problem is still [[1751: Movie Folder|all those Titanics]] to watch out for? [[Special:Contributions/82.132.237.203|82.132.237.203]] 16:25, 2 December 2025 (UTC) ;)

872: Fairy Tales

2025-12-02T16:08:26Z

82.132.237.203: /* Explanation */ Self-corrections/rewrites, plus some other bits.

{{comic
| number = 872
| date = March 14, 2011
| title = Fairy Tales
| image = fairy tales.png
| titletext = Goldilocks' discovery of Newton's method for approximation required surprisingly few changes.
}}

==Explanation==
{{w|Eigenvalues and eigenvectors|Eigenvectors}} are a mathematical concepts that can be applied to a {{w|Matrix (mathematics)|matrix}}. A matrix is mostly displayed as an rectangular array of elements used to describe the state of objects in physics. In pure mathematics they can be much more complex. The most important issue to the understanding of the comic is that a matrix can be transformed through various processes. These transformations can include rotation, movement and scaling of the object described by the matrix. An eigenvector refers to elements of the vector space of the matrix which remain unchanged (except possibly being scaled to be longer or shorter) after the transformation is applied. The prefix 'eigen-' applied to the term is adopted from the German word ''eigen'' for "self-" or "unique to", "peculiar to", or "belonging to." As the eigenvector remains unchanged through the transformation of the matrix it can be used to describe something unique about that matrix.

The story of Cinderella includes Cinderella going to a ball in disguise, dancing with a prince and then leaving early and quickly, so that she accidentally leaves a very particular shoe behind. The versions of primarily French origin, that ultimately became widespread in English, tend to describe a glass slipper (with the possible origin of the '{{wiktionary|verre#Noun 2|glass}}' originally being '{{w|Vair|fur}}'), while the Germanic tradition (often via {{w|Grimms' Fairy Tales}}) make use of golden footware, as do many non-European equivalent tales if they don't use other materials. The prince then uses the shoe's apparently unique fit to identify Cinderella from amongst all the possible candidates. [[Megan]] says that, the way she learned it, the prince used an eigenvector and corresponding eigenvalue to match the shoe to its owner. Eigenvectors are a basis of statistical {{w|principal component analysis}}, a procedure in which a set of points in N-dimensional space (each of which represents an observation) are rotated in such a way that the cloud of points has its largest extent along the X-axis, then along the Y-axis, and so on. The prince could probably use this procedure on the inner dimensions first of {{w|Cinderella}}'s shoe and then also all candidate feet to determine their respective degree of fit, although it would be an extremely complicated way to do this compared to just directly comparing like-for-like measurements with a ruler or tailor's tape.

Megan explains that her mother, a math professor (drawn as [[Hairbun]] with glasses) would continue to talk when she fell asleep in the midst of reading bed time stories, and then would ramble on mixing the adventures with the math from her work. The middle panel refers to the story of {{w|The Ant and the Grasshopper}} with the addition of what is likely a reference to the {{w|Poincaré conjecture}}, a (now-misnamed) theorem in mathematics.

Megan explains that even today she is not sure which versions are the real ones. Cueball cannot understand how she would not have noticed the drastic subject changes (which seems obvious to adults, but maybe not to small children).

Megan then mentions two other story changes, the first ''Inductive White and the (''n''−1) Dwarfs'' was better than the original. The story is a combination of {{w|Snow White and the Seven Dwarfs}} with the {{w|Mathematical induction|principle of induction}}. But ''The limx→∞(x) Little Pigs'' was a little weird toward the end. That story combines the {{w|Three Little Pigs}} with {{w|Limit (mathematics)|mathematical limits}}. The reason it got weird toward the end (probably even weirder than ''[[821: Five-Minute Comics: Part 3|The 119 Little Pigs]] did'') was likely because the number of pigs tends to infinity as the story progresses, and this also makes it difficult to see how there {{w|Zeno's paradoxes|could be}} an actual end.

Each of the stories has a varied degree of similarity to the mathematical concepts that were mixed in as though her mom began to talk about a mathematical principle that may have been brought to mind while reading the story or already on her mind.

In the title text Megan mentions another adventure: ''Goldilocks' discovery of Newton's method for approximation''. {{w|Newton's method}} for approximation is a method for finding successively better approximations to the zeroes (or roots) of a real-valued function. In {{w|The Story of the Three Bears|Goldilocks}}, the protagonist finds successively better porridge and comfier chairs in a house where three bears lived. In the same way, in the Mom's version of the fairy tale, she would find successively better approximations to zeroes instead of successively better bowls of porridge, and Megan notes that it was surprising how few changes that story needed compared to the original adventure.

==Transcript==
:[Megan sits in an armchair, reading a book looking over her shoulder at Cueball as he walks in.]
:Megan: Are there eigenvectors in ''Cinderella?''
:Cueball: ...No?
:Megan: The prince didn't use them to match the shoe to its owner?
:Cueball: What are you ''talking'' about?
:Megan: Dammit.

:[In this frame-less panel Megan is shown in a flashback as a little girl lying in bed, head on pillow and hands held on the edge of the blanket at her throat. Hairbun with glasses, as her mom, is sitting on the edge of the bed reading, while her head is hanging down. Above and below there are two frames with Megan's narration. Hairbun's reading text is smaller than the other text in this comic.]
:Megan (narrating): My mom is one of those people who falls asleep while reading, but keeps talking. She's a math professor, so she'd start rambling about her work.
:Mom: But while the ant gathered food ...
:Mom: ...zzzz...
:Mom: ...the grasshopper contracted to a point on a manifold that was ''not'' a 3-sphere...
:Megan (narrating): I'm still not sure which versions are real.

:[Cueball now stands in front of the arm chair. Megan has put the book away, and is leaning her head on her left arm which rests on the armrest of the chair.]
:Cueball: You didn't notice the drastic subject changes?
:Megan: Well, sometimes her versions were better. We loved ''Inductive White and the (n−1) Dwarfs''.
:Megan: I guess ''The limx→∞(x) Little Pigs'' did get a bit weird toward the end...

{{comic discussion}}

[[Category:Comics featuring Megan]]
[[Category:Comics featuring Cueball]]
[[Category:Comics featuring Hairbun]]
[[Category:Comics featuring real people]] 
[[Category:Fiction]]
[[Category:Math]]

872: Fairy Tales

2025-12-02T15:55:55Z

82.132.237.203: /* Explanation */ Rewrite the rewrite a bit. (And a bit more.) Didn't go into the old 'theory' that the "fur slipper" was Cinderella's pubic area, into which the *Prince* decided he himself could satisfactorally 'fit' his own. ;)

{{comic
| number = 872
| date = March 14, 2011
| title = Fairy Tales
| image = fairy tales.png
| titletext = Goldilocks' discovery of Newton's method for approximation required surprisingly few changes.
}}

==Explanation==
{{w|Eigenvalues and eigenvectors|Eigenvectors}} are a mathematical concepts that can be applied to a {{w|Matrix (mathematics)|matrix}}. A matrix is mostly displayed as an rectangular array of elements used to describe the state of objects in physics. In pure mathematics they can be much more complex. The most important issue to the understanding of the comic is that a matrix can be transformed through various processes. These transformations can include rotation, movement and scaling of the object described by the matrix. An eigenvector refers to elements of the vector space of the matrix which remain unchanged (except possibly being scaled to be longer or shorter) after the transformation is applied. The prefix 'eigen-' applied to the term is adopted from the German word ''eigen'' for "self-" or "unique to", "peculiar to", or "belonging to." As the eigenvector remains unchanged through the transformation of the matrix it can be used to describe something unique about that matrix.

The story of Cinderella includes Cinderella going to a ball in disguise, dancing with a prince and then leaving early and quickly, so that she accidentally leaves a very particular shoe behind. The versions of French, and ultimately widespread in English, origin tend to use a glass slipper (with the possible origin of the {{wiktionary|verre#Noun 2|glass}} originally being {{w|Vair|fur}}), while the Germanic tradition (often via {{w|Grimms' Fairy Tales}}) may use of golden footware, as do many non-European equivalent tales if they don't use other materials. The prince then uses the shoe's unique fit to identify Cinderella from amongst all the possible candidates. [[Megan]] says that, the way she learned it, the prince used an eigenvector and corresponding eigenvalue to match the shoe to its owner. Eigenvectors are a basis of statistical {{w|principal component analysis}}, a procedure in which a set of points in N-dimensional space (each of which represents an observation) are rotated in such a way that the cloud of points has its largest extent along the X-axis, then along the Y-axis, and so on. The prince could probably use this procedure on the inner dimensions first of {{w|Cinderella}}'s shoe and then also all candidate feet to determine their respective degree of fit, although it would be an extremely complicated way to do this compared to just directly comparing like-for-like measurements with a ruler or tailor's tape.

Megan explains that her mother, a math professor (drawn as [[Hairbun]] with glasses) would continue to talk when she fell asleep in the midst of reading bed time stories, and then would ramble on mixing the adventures with the math from her work. The middle panel refers to the story of {{w|The Ant and the Grasshopper}} with the addition of what is likely a reference to the {{w|Poincaré conjecture}}, a (now-misnamed) theorem in mathematics.

Megan explains that even today she is not sure which versions are the real ones. Cueball cannot understand how she would not have noticed the drastic subject changes (which seems obvious to adults, but maybe not to small children).

Megan then mentions two other story changes, the first ''Inductive White and the (''n''−1) Dwarfs'' was better than the original. The story is a combination of {{w|Snow White and the Seven Dwarfs}} with the {{w|Mathematical induction|principle of induction}}. But ''The limx→∞(x) Little Pigs'' was a little weird toward the end. That story combines the {{w|Three Little Pigs}} with {{w|Limit (mathematics)|mathematical limits}}. The reason it got weird toward the end was (likely) because the number of pigs tends to infinity as the story progresses.

Each of the stories has a varied degree of similarity to the mathematical concepts that were mixed in as though her mom began to talk about a mathematical principle that may have been brought to mind while reading the story or already on her mind.

In the title text Megan mentions another adventure: ''Goldilocks' discovery of Newton's method for approximation''. {{w|Newton's method}} for approximation is a method for finding successively better approximations to the zeroes (or roots) of a real-valued function. In {{w|The Story of the Three Bears|Goldilocks}}, the protagonist finds successively better porridge and comfier chairs in a house where three bears lived. In the same way, in the Mom's version of the fairy tale, she would find successively better approximations to zeroes instead of successively better bowls of porridge, and Megan notes that it was surprising how few changes that story needed compared to the original adventure.

==Transcript==
:[Megan sits in an armchair, reading a book looking over her shoulder at Cueball as he walks in.]
:Megan: Are there eigenvectors in ''Cinderella?''
:Cueball: ...No?
:Megan: The prince didn't use them to match the shoe to its owner?
:Cueball: What are you ''talking'' about?
:Megan: Dammit.

:[In this frame-less panel Megan is shown in a flashback as a little girl lying in bed, head on pillow and hands held on the edge of the blanket at her throat. Hairbun with glasses, as her mom, is sitting on the edge of the bed reading, while her head is hanging down. Above and below there are two frames with Megan's narration. Hairbun's reading text is smaller than the other text in this comic.]
:Megan (narrating): My mom is one of those people who falls asleep while reading, but keeps talking. She's a math professor, so she'd start rambling about her work.
:Mom: But while the ant gathered food ...
:Mom: ...zzzz...
:Mom: ...the grasshopper contracted to a point on a manifold that was ''not'' a 3-sphere...
:Megan (narrating): I'm still not sure which versions are real.

:[Cueball now stands in front of the arm chair. Megan has put the book away, and is leaning her head on her left arm which rests on the armrest of the chair.]
:Cueball: You didn't notice the drastic subject changes?
:Megan: Well, sometimes her versions were better. We loved ''Inductive White and the (n−1) Dwarfs''.
:Megan: I guess ''The limx→∞(x) Little Pigs'' did get a bit weird toward the end...

{{comic discussion}}

[[Category:Comics featuring Megan]]
[[Category:Comics featuring Cueball]]
[[Category:Comics featuring Hairbun]]
[[Category:Comics featuring real people]] 
[[Category:Fiction]]
[[Category:Math]]