https://www.explainxkcd.com/wiki/api.php?action=feedcontributions&user=188.114.102.94&feedformat=atomexplain xkcd - User contributions [en]2024-03-29T15:13:47ZUser contributionsMediaWiki 1.30.0https://www.explainxkcd.com/wiki/index.php?title=2293:_RIP_John_Conway&diff=1907832293: RIP John Conway2020-04-17T14:35:01Z<p>188.114.102.94: Correction regarding the topology of the grid, here the actual grid clearly goes beyond the frame and its topology cannot be known</p>
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<div>{{comic<br />
| number = 2293<br />
| date = April 13, 2020<br />
| title = RIP John Conway<br />
| image = rip_john_conway.gif<br />
| titletext = 1937-2020<br />
}}<br />
<br />
==Explanation==<br />
{{incomplete|Created by a GLIDER. Needs more in-depth explanation of how the Game Evolves. Include remaining stills from the GIF in the table below. Should also expand more on why Conway is a person of note. Do NOT delete this tag too soon.}}<br />
{{w|John Horton Conway|John Conway}}, an English mathematician, passed away of [[:Category:COVID-19|COVID-19]] on April 11, 2020. Two days later, [[Randall]] created this [[:Category:Tribute|memorial comic]]. It is the 6th memorial comic, but it is the first released in almost 5 years, since [[1560: Bubblegum]].<br />
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One of Conway's most famous creations was the {{w|cellular automaton}} known as {{w|Conway's Game of Life}}. A cellular automaton is a machine composed of cells, each of which can be in a different state. Every generation, each cell in the automaton may transition to a new state depending on a set of rules. (Conway's work in mathematics was vast and various, but he is perhaps best known in the field for discovering the {{w|surreal numbers}}, which inspired Donald Knuth to write a novel which may have been referenced back in [[505: A Bunch of Rocks]].)<br />
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Conway's Game of Life was first popularized to the general public in the form of a game, Life Genesis, bundled into some distributions of Windows 3.1, an operating system from the early-90s that Randall most likely used in his preteen years.<br />
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Conway's Game of Life is a 2-state automaton (i.e., every cell can be "alive" or "dead") that is implemented on a two-dimensional grid of cells using the {{w|Moore neighborhood}} - this means that each cell can only be influenced by the eight cells directly surrounding it, both orthogonally and diagonally. The transition rules that Conway discovered are as follows:<br />
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* If an "alive" cell has no live neighbors, or only one live neighbor, it becomes "dead". (This simulates death by isolation).<br />
* If an "alive" cell has four or more live neighbors, it becomes "dead". (This simulates death by overcrowding).<br />
* If a "dead" cell has exactly three live neighbors, it becomes "alive". (This simulates birth).<br />
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Despite the simplicity of these three rules, Conway showed that patterns of amazing complexity can nonetheless develop out of simple cell arrangements. Some patterns do not evolve at all ("still lifes"), some enter a cyclic, repeating state ("oscillators"), and some reproduce their own pattern displaced by an offset, resulting in patterns that can move across the grid under their own power ("gliders" and "spaceships"). This last category is of particular interest, as it allows the Game of Life to transmit information from one location to another, allowing for rich, dynamic behavior and even for the creation of computational machines within the automaton itself.<br />
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This comic begins with the shape of a stick figure as the starting cell configuration of the Game of Life. The black cells are "alive" and the white cells are "dead". This configuration then evolves via Conway's rules, disintegrating into nothingness except for a five-cell pattern known as a "glider", which ascends up and to the right. This visually suggests a "soul" breaking away from the disintegrating corporeal body. The glider is perhaps the most iconic pattern of the Game of Life, and is often used symbolically to represent the phenomenon of emergence. <br />
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Here the topology of the grid on which the cells evolve is not known, the cellular automaton can be run on many topologies, for example you can choose to make cells reappear from the opposite side once they reach an edge (similarly to the behaviour of the well known Pacman). Here once the glider reaches the top right, we know for sure that the actual grid is bigger (since the glider leaves the frame while continuing its pattern), and we are only seeing part of the full grid.<br />
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The initial state presented in the comic does actually evolve in that manner, as can be verified by entering the pattern into a cellular automaton simulator such as [http://golly.sourceforge.net/ Golly] or web services such as [https://bitstorm.org/gameoflife/ this one]. It seems that no one else have created this pattern before. At least, despite discussion in the comments, no one has found anything to show that this is not Randall's own discovery of this pattern. <br />
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The title text simply states Conway's birth and death year: 1937-2020.<br />
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Conway's Game of Life was previously mentioned in [[696: Strip Games]]. Cellular automata was also referenced in [[505: A Bunch of Rocks]].<br />
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This comic is the 18th comic in a row (not counting the [[2288: Collector's Edition|April Fools' comic]]) in a [[:Category:COVID-19|series of comics]] related to the {{w|2019–20 coronavirus outbreak|2020 pandemic}} of the {{w|coronavirus}} {{w|SARS-CoV-2}}, which causes {{w|COVID-19}}. Although this comic is, of course, mainly a tribute to John Conway, the fact that he died of COVID-19 in the middle of this long series of corona related comics by Randall is relevant.<br />
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==Table of generations==<br />
{| class="wikitable"<br />
!Generation<br />
!Notes<br />
|-<br />
|[[File:Generation 0.jpg|thumb]]||Starting state (or "zeroth generation").<br />
|-<br />
|[[File:Generation 1.jpg|thumb]]||First generation. Note that this image is not aligned with the previous one: the position of all cells has shifted downward by one cell. All further generations are aligned the same as this one.<br />
|-<br />
|[[File:Generation 2.jpg|thumb]]||Second generation.<br />
|-<br />
|[[File:Generation 3.jpg|thumb]]||Third generation.<br />
|-<br />
|[[File:Generation 4.jpg|thumb]]||Fourth generation.<br />
|-<br />
|[[File:Generation 5.jpg|thumb]]||Fifth generation.<br />
|-<br />
|[[File:Generation 6.jpg|thumb]]||Sixth generation. The first appearance of the glider, a well-known formation in Conway's Game of Life.<br />
|-<br />
|[[File:Generation 7.jpg|thumb]]||Seventh generation. The glider takes on its other shape.<br />
|-<br />
|[[File:Generation 8.jpg|thumb]]||Eighth generation. The glider returns to its first shape, pointing right instead of up.<br />
|-<br />
|[[File:Generation 9.jpg|thumb]]||Ninth generation. The glider's second shape again, pointing right instead of up.<br />
|-<br />
|[[File:Generation 10.jpg|thumb]]||Tenth generation. The glider is now in its original form, but one cell higher and one cell to the right. It will continue to progress, cycling through these four states every four generations. The remains of the chaos down below will take two more generations to disappear completely.<br />
|}<br />
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==Transcript==<br />
:[A pixelated image of a stick figure using 21 pixels, could be a pixel Cueball, which waves with one hand up while holding the other hand down. The head consist of 7 pixels, the top row of three having two pixels beneath the two outer pixels, thus having two empty pixels beneath the central pixel. The neck and torso is a typical cross made from six pixels. The two legs are two pixels each shifted left and right of the cross. The arm to the left that waves is two pixels one down and the next back up to the level of the cross central beam. The arm to the right has the first pixel similarly but the second pixel continues one further step down. After less than one second it turns out that the image is animated, with the pixels changing according to the rules of Conway's Game of Life. The figure splits into three groups, two of which dissipates in a similar way at the bottom of the panel. The other becomes a 'glider' and moves off to the top-right corner of the image and out of the frame. The animation then repeats.]<br />
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{{comic discussion}}<br />
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[[Category:Tribute]]<br />
[[Category:COVID-19]]<br />
[[Category:Comics with animation]]<br />
[[Category:Comics featuring real people]]</div>188.114.102.94https://www.explainxkcd.com/wiki/index.php?title=Talk:2233:_Aurora_Meaning&diff=186478Talk:2233: Aurora Meaning2020-01-26T11:59:12Z<p>188.114.102.94: </p>
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<div><!--Please sign your posts with ~~~~ and don't delete this text. New comments should be added at the bottom.--><br />
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Hey guys. As you can tell by the edit logs, I'm removing a spam comment that was made in bad faith. I'm new here so please let me know what the actual procedure is for, ya know, spam deletion and logging. <br />
Have an outstanding day, --[[User:OtterlyAmazin|OtterlyAmazin]] ([[User talk:OtterlyAmazin|talk]]) 03:46, 26 November 2019 (UTC)<br />
:Great you removed [https://www.explainxkcd.com/wiki/index.php?title=Talk%3A2233%3A_Aurora_Meaning&type=revision&diff=183613&oldid=183612 this text]. I guess if this account keeps doing such things it should be banned. Sadly we seem to have lost all contact to any admin of the page...? So I'm not sure how we could do anything. --[[User:Kynde|Kynde]] ([[User talk:Kynde|talk]]) 08:01, 26 November 2019 (UTC)<br />
::Wow, yeah, that looks obnoxious, good job clearing it out, thanks! [[User:NiceGuy1|NiceGuy1]] ([[User talk:NiceGuy1|talk]]) 04:39, 5 January 2020 (UTC)<br />
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Nobody talks about the visible shadow of the two lower texts? You can clearly see a layer of grey letters, not identical to the topmost layer, benath. [[Special:Contributions/172.68.141.52|172.68.141.52]] 05:57, 26 November 2019 (UTC)<br />
:I have no idea what you are talking about. I see no shadows on neither xkcd or the image uploaded here? Maybe it is your device that is making the shadows... --[[User:Kynde|Kynde]] ([[User talk:Kynde|talk]]) 08:01, 26 November 2019 (UTC)<br />
::On the words Satelite and Exciting in the southern hemisphere it is most visible (but also on others) that there are greyish letters right next to the black ones, kinda like shadows. Maybe Randall copy pasted and changed it. Similar things of remains of erased parts have been visible before. (If someone thinks it is important, I can try to look it up, but I am not exactly sure where it was) --[[User:Lupo|Lupo]] ([[User talk:Lupo|talk]]) 08:38, 26 November 2019 (UTC)<br />
::: You're right. It's most visible on the right side of the loop in the 'S' at the end of 'Satellites' in the southern hemisphere, but you can also see it on the lower tip of 'C' and the upper tip of 'G' in 'Exciting'. However, I downloaded the image and used an image editor to up the contrast, and it turns out the grey letters are the exact same as the black ones, just in slightly different places and shapes. Presumably Randal didn't like his first attempt at lettering the comic and erased it and rewrote it. [[Special:Contributions/162.158.126.136|162.158.126.136]] 05:58, 27 November 2019 (UTC)<br />
::::I see it most in "exciting", on the C and G. My theory: He wrote it manually, but didn't like it, or didn't like that it didn’t match the Northern Hemisphere version, used an erase tool that actually blends to the background colour, and Copied / Pasted it. Can anybody use a paint tool to see if the current version is now an exact match? [[User:NiceGuy1|NiceGuy1]] ([[User talk:NiceGuy1|talk]]) 04:39, 5 January 2020 (UTC) <br />
:That is known as "mustard". This term originated in the OTT, of course[[Special:Contributions/172.69.63.191|172.69.63.191]] 16:34, 27 November 2019 (UTC)<br />
::What does this comment even mean? I have no idea what "OTT" means and what the term "mustard" refers to in either the comic or any previous comments! Can the OP or anyone else shed some light on it? [[User:Ianrbibtitlht|Ianrbibtitlht]] ([[User talk:Ianrbibtitlht|talk]]) 17:48, 27 November 2019 (UTC)<br />
:::The OTT (short for the One True Thread) is the unofficial nickname for the xkcd fora thread for Time (also known over there as the One True Comic (OTT for short). Mustard arose when some mistakes in colouration were made during Time's run that appeared as outlines is a faintly mustard-like colour. Hope that's of any help. [[Special:Contributions/162.158.150.118|162.158.150.118]] 15:41, 28 November 2019 (UTC)<br />
::::Since this seems like it was meant to be a reply to the "shadow" comment above, I increased the indentation to show that better and hopefully clarify better. Thanks Mr/Ms 162.158, I was at a loss too. :) [[User:NiceGuy1|NiceGuy1]] ([[User talk:NiceGuy1|talk]]) 04:45, 5 January 2020 (UTC)<br />
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Do we have any indication how much energy we're talking to see the aurora at the equator? or how that would physically work? [[Special:Contributions/162.158.159.38|162.158.159.38]] 08:17, 26 November 2019 (UTC)<br />
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There has been an equatorial aurora exactly once in human history. [https://en.wikipedia.org/wiki/Starfish_Prime Starfish Prime] was an orbital nuclear detonation that, among other things, disabled multiple satellites and created a temporary artificial aurora 16° north. That is also likely what the sub-tropical band is referring to. [[Special:Contributions/162.158.150.88|162.158.150.88]] 09:12, 26 November 2019 (UTC)<br />
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What should "Subpolar latitudes" include for the southern hemisphere? Southern Africa? Southern Australia? Since I'm in the northern hemisphere, I don't know what's appropriate for the other half of the world. [[User:Ianrbibtitlht|Ianrbibtitlht]] ([[User talk:Ianrbibtitlht|talk]]) 22:46, 26 November 2019 (UTC)<br />
:Most of the subpolar latitudes of the southern hemisphere are ocean. Southern Australia is still subtropical. The southernmost parts of Chile and Argentina (Terra del Fuego) would qualify.<br />
::umm, it is actually possible to see the aurora australis from the southern parts of Australia. https://www.abc.net.au/news/2019-06-14/aurora-australia-watching-and-photographing-the-southern-lights/11197868 and the southern parts of Australia, whilst capable of getting very warm in summer, are definitely not subtropical[[User:Boatster|Boatster]] ([[User talk:Boatster|talk]]) 10:32, 2 December 2019 (UTC)<br />
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In Principal Skinner's kitchen: You are about to enjoy delicious steamed hams. ―[[User:TobyBartels|TobyBartels]] ([[User talk:TobyBartels|talk]]) 13:00, 5 December 2019 (UTC)<br />
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== Saturn's out of place H3+ Aurorae and Ring Decay ==<br />
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Wondering if this might have been inspired by James O’Donoghue discovery of decay of Saturn's rings.<br />
“I thought it could be some new band of aurora which had never been seen before or something entirely new. Those were the two options now, and both were amazing.”<br />
Read more: https://www.smithsonianmag.com/science-nature/saturns-rings-are-slowly-disappearing-180972856/#dL7Me0SVImIcFSRq.99<br />
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The loss or reorientation of the magnetic field of the earth would probably result in frequent equatorial auroras.<br />
[[Special:Contributions/188.114.102.94|188.114.102.94]] 11:59, 26 January 2020 (UTC)</div>188.114.102.94https://www.explainxkcd.com/wiki/index.php?title=Talk:2073:_Kilogram&diff=166018Talk:2073: Kilogram2018-11-16T17:10:12Z<p>188.114.102.94: </p>
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<div><!--Please sign your posts with ~~~~ and don't delete this text. New comments should be added at the bottom.--><br />
I didn't know that weights and currencies could be converted 1:1, that's cool! [[User:Fabian42|Fabian42]] ([[User talk:Fabian42|talk]]) 16:37, 16 November 2018 (UTC)<br />
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I wish they ''had'' redefined the kilogram a little bit. It would have been neat if 1 kg was exactly the weight of 1 dm^3 (1 litre) of water under one atmosphere of pressure. Right now it's soooo close. It's a good enough estimate for simple maths, but whenever you tell people that a litre of water weighs one kilogram the pedants comes out of the woodworks... [[User:Kapten-N|Kapten-N]] ([[User talk:Kapten-N|talk]]) 16:50, 16 November 2018 (UTC)<br />
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Welp, looks like 1 kg, a.k.a. 1 lb, a.k.a 2.2 lb, is now officially defined to have zero mass.<br />
[[Special:Contributions/172.69.50.28|172.69.50.28]] 16:56, 16 November 2018 (UTC)<br />
:…or infinite. [[User:Fabian42|Fabian42]] ([[User talk:Fabian42|talk]]) 16:59, 16 November 2018 (UTC)<br />
::What I understand: the joke is not (only) about 1 (old) kg = 1 (old) lb, but (also) about 1 new kg = 1 old lb... or 1 new lb = 1 old kg :^) Or about a ring of positive characteristic --[[Special:Contributions/188.114.102.94|188.114.102.94]] 17:08, 16 November 2018 (UTC)</div>188.114.102.94https://www.explainxkcd.com/wiki/index.php?title=Talk:2073:_Kilogram&diff=166017Talk:2073: Kilogram2018-11-16T17:08:54Z<p>188.114.102.94: </p>
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<div><!--Please sign your posts with ~~~~ and don't delete this text. New comments should be added at the bottom.--><br />
I didn't know that weights and currencies could be converted 1:1, that's cool! [[User:Fabian42|Fabian42]] ([[User talk:Fabian42|talk]]) 16:37, 16 November 2018 (UTC)<br />
<br />
I wish they ''had'' redefined the kilogram a little bit. It would have been neat if 1 kg was exactly the weight of 1 dm^3 (1 litre) of water under one atmosphere of pressure. Right now it's soooo close. It's a good enough estimate for simple maths, but whenever you tell people that a litre of water weighs one kilogram the pedants comes out of the woodworks... [[User:Kapten-N|Kapten-N]] ([[User talk:Kapten-N|talk]]) 16:50, 16 November 2018 (UTC)<br />
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Welp, looks like 1 kg, a.k.a. 1 lb, a.k.a 2.2 lb, is now officially defined to have zero mass.<br />
[[Special:Contributions/172.69.50.28|172.69.50.28]] 16:56, 16 November 2018 (UTC)<br />
:…or infinite. [[User:Fabian42|Fabian42]] ([[User talk:Fabian42|talk]]) 16:59, 16 November 2018 (UTC)<br />
::What I understand: the joke is not (only) about 1 (old) kg = 1 (old) lb, but (also) about 1 new kg = 1 old lb... or 1 new lb = 1 old kg :^) --[[Special:Contributions/188.114.102.94|188.114.102.94]] 17:08, 16 November 2018 (UTC)</div>188.114.102.94https://www.explainxkcd.com/wiki/index.php?title=2063:_Carnot_Cycle&diff=1646432063: Carnot Cycle2018-10-24T16:08:16Z<p>188.114.102.94: /* Explanation */</p>
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<div>{{comic<br />
| number = 2063<br />
| date = October 24, 2018<br />
| title = Carnot Cycle<br />
| image = carnot_cycle.png<br />
| titletext = The Carnot cycle is more properly known by its full title, the "Carnot-Tolkien-Wagner Ring Cycle."<br />
}}<br />
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==Explanation==<br />
{{incomplete|Please edit the explanation below and only mention here why it isn't complete. Do NOT delete this tag too soon.}}<br />
The Carnot cycle is a theoretical thermodynamic cycle and is covered in most thermodynamics classes which looks very much like the figure drawn.<br />
However in this case, Randall has replaced the labels of the 4 stages of the real Carnot cycle with new ones.<br />
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Each step is explained below<br />
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{| class="wikitable sortable"<br />
!style="width:10%"|Step<br />
!style="width:10%"|Real Carnot Cycle Name<br />
!style="width:80%"|Explanation<br />
|-<br />
|1<br />
|Reversible isothermal expansion of the gas at the "hot" temperature, Th (isothermal heat addition or absorption).<br />
|<br />
|-<br />
|2<br />
|Isentropic (reversible adiabatic) expansion of the gas (isentropic work output).<br />
||-<br />
|-<br />
|3<br />
|Reversible isothermal compression of the gas at the "cold" temperature, Tc. (isothermal heat rejection)<br />
|-<br />
|4<br />
|Isentropic compression of the gas (isentropic work input).<br />
|<br />
|}<br />
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==Transcript==<br />
{{incomplete transcript|Do NOT delete this tag too soon.}}<br />
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{{comic discussion}}</div>188.114.102.94