https://www.explainxkcd.com/wiki/api.php?action=feedcontributions&user=198.41.238.82&feedformat=atomexplain xkcd - User contributions [en]2024-03-29T09:30:15ZUser contributionsMediaWiki 1.30.0https://www.explainxkcd.com/wiki/index.php?title=Talk:1930:_Calendar_Facts&diff=164156Talk:1930: Calendar Facts2018-10-13T03:13:02Z<p>198.41.238.82: added my missing comment</p>
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Shouldn't it be "libration" not "libation"? Pretty sure drinking has nothing to do with it. Also pretty sure this is a mistake and not a clever alteration. [[Special:Contributions/162.158.62.57|162.158.62.57]] 16:41, 18 December 2017 (UTC)<br />
:No, it's a clever alteration because "libration" is listed right above it. --[[User:Videblu|Videblu]] ([[User talk:Videblu|talk]]) 16:45, 18 December 2017 (UTC)<br />
::That's just a mistake - he meant to write 'vibration'[[Special:Contributions/141.101.76.16|141.101.76.16]] 16:48, 18 December 2017 (UTC)<br />
:::'Vibration' wouldn't make any sense, 'libation' is at least humorous, I vote it was no mistake. [[Special:Contributions/172.68.54.64|172.68.54.64]] 18:00, 18 December 2017 (UTC)<br />
::::You're right - I don't know what I could have been thinking...[[Special:Contributions/141.101.76.16|141.101.76.16]] 08:49, 19 December 2017 (UTC)<br />
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I formatted the transcript into a bullet tree since I thought it was the closest equivalent you can get in plain text to the branching flowchart deal in the comic. I'm open to alternative suggestions. The biggest problem I encountered, and one I'd like to see resolved, is what to do in the case where two branching sections butt up against each other, e.g. winter/summer and solstice/Olympics. I used an arrow symbol ("→") on an in-between line just to separate the set of bullets, but if someone wants to change that, I'm up for it. [[User:Kenbellows|Kenbellows]] ([[User talk:Kenbellows|talk]]) 18:04, 18 December 2017 (UTC)<br />
:I find the bullet tree legible for the last few long lines, but it's hard to follow a single path. I was thinking of using (option 1|option 2) syntax, but that would probably look messy too. [[Special:Contributions/162.158.91.29|162.158.91.29]] 18:10, 18 December 2017 (UTC)<br />
:I think indenting when lines diverge and un-indenting when they converge would make it look nice and be easy to follow. I'm willing to do the work if others agree. [[Special:Contributions/162.158.74.9|162.158.74.9]] 23:58, 18 December 2017 (UTC)<br />
::Could you do it? I don't see what it looks like. Is it similar to [http://www.explainxkcd.com/wiki/index.php?title=1930:_Calendar_Facts&oldid=14939 this]? [[Special:Contributions/162.158.88.68|162.158.88.68]] 06:16, 19 December 2017 (UTC)<br />
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Random error noticed - the line connecting "International Date" and "Mason-Dixon" to "Line" is drawn in the wrong color. [[Special:Contributions/162.158.75.136|162.158.75.136]] 18:57, 18 December 2017 (UTC)<br />
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Isn't the point with this comic that there is at least one valid path for every included element? I don't think Randall intended it to be a factorial combination because as the explanation suggests, most would be wrong/absurd/silly. But why not instead try to find some invalid element when it can be included in any possible path from end to end? Toyota Truck Month or Shark Week might not happen next year, who knows? Can anyone find any element that has no valid path at all? If not, then maybe the main explanation should be updated to fit the model recommended here.[[User:Lunar7|Lunar7]] ([[User talk:Lunar7|talk]]) 20:05, 18 December 2017 (UTC)<br />
:I'm not sure there's any 'fact' that could be constructed that 'scientists are really worried' about. Unless it's something to do with Shark Week. Although having said that, it doesn't actually say that they're worried 'about it', so I guess you could append this to any otherwise true fact and still have something true, albeit non sequitous. [[Special:Contributions/141.101.76.16|141.101.76.16]] 08:53, 19 December 2017 (UTC)<br />
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I'm pretty sure the whole point of this comic was to be a "screw you" to the Explain XKCD crew. Way to roll with the punches. {{unsigned ip|172.68.174.16}}<br />
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;Generators<br />
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[https://www.pibweb.com/xkcd_calendar.php PIBWEB online generator of Calendar 'facts'] using this formula.<br />
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http://calendarfact.com/ (https://github.com/mstratman/calendarfact)<br />
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https://staab.github.io/xkcd-1930/<br />
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: Not sure who's responsible for this, but there seem to be a few errors. "Might (not happen/happen twice) this year" is missing "this year", and "the (harvest/super/blood) moon" is similarly missing "moon". Also, I see a part "happens at the same time every year" that I don't see in the comic. Are there any other additions; and is there a way to find them other than keep refreshing? -- [[User:Angel|Angel]] 18:40, 18 December 2017 (UTC)<br />
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:: Checked the source; looks like "at the same time" replaces "at the wrong time". Also, some of the options are missing a "." between the main tree and the title text or at the end of the sentence. (And for some reason every time I go to edit this talk page, the wiki logs me out) -- [[Special:Contributions/162.158.91.167|162.158.91.167]] 18:48, 18 December 2017 (UTC)<br />
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: The source is on [https://github.com/staab/xkcd-1930 github] - you can add pull requests to fix errors (I'll take care of the aforementioned errors).<br />
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Here's mine.<br />
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http://www.hearn.to/calendar.html<br />
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[[Special:Contributions/172.68.142.65|172.68.142.65]]<br />
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Here's one I wrote on jsFiddle. Glad I'm not the only one who read this and immediately thought, "I must code this!" [[Special:Contributions/172.68.34.64|172.68.34.64]] 21:29, 18 December 2017 (UTC)<br />
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https://jsfiddle.net/qa290hss/3/<br />
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Here's a GraphML gist that I knocked up:<br />
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https://gist.github.com/GeoSpark/0c64cb85ca8927175892f43f23ba1bdb<br />
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The only change I made was to "precession", "libration", etc by adding the word "the" in front because it reads better. At least to my British English sensibilities. YLMV.<br />
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I tuned it into a twitter bot: http://twitter.com/xkcd_cal_facts. It’s built using Tracery and cheapbotsdonequick.com<br />
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https://codepen.io/DouglasMeyer/full/YYqKzX/<br />
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I made one too! https://jsfiddle.net/kr661rhy/<br />
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Here's my python implementation (it ain't pretty, but then I'm not very good at python yet, either): <br />
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https://github.com/aroaminggeek/xkcd-calendar-facts-python/<br />
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And my Crystal implementation: <br />
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https://github.com/aroaminggeek/xkcd-calendar-facts-crystal/<br />
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As there are many generators isn't better to remove links to generators from the comic explanation and add a link to this section?<br />
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Here is my implementation in '''Haskell''':<br />
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https://github.com/mwuttke97/xkcd1930<br />
[[Special:Contributions/162.158.90.222|162.158.90.222]] 19:57, 20 December 2017 (UTC)<br />
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I made a '''Python''' command and function;<br />
* Package: https://pypi.python.org/pypi/calendar-fact<br />
* Source: https://gitlab.com/uda/calendar-fact<br />
[[User:YehudaDe|YehudaDe]] ([[User talk:YehudaDe|talk]]) 08:43, 21 December 2017 (UTC)<br />
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I wrote a command line tool in '''node.js'''. My code's pretty concise because it doesn't hard code all possible options for each "piece" but uses the "(choice|choice|choice)" syntax. <br />
* Package: https://npmjs.com/package/xkcd-calendar-facts<br />
* Source: https://github.com/shreyasminocha/calendar-facts {{unsigned ip| 172.68.144.211}}<br />
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I created a human-readable file format to represent structures like the one in the comic, then wrote a '''C''' program to parse those files, so now you can write your own calendar facts.<br />
* Source: https://github.com/saucecode/adventure-sets [[Special:Contributions/198.41.238.82|198.41.238.82]] 03:13, 13 October 2018 (UTC)<br />
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;Equinox<br />
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I don't think this is the correct definition for equinox, the plane comprising the Earth orbit around the Sun is never perpendicular to the Earth's axis. During the equinox the sun rays arrive to the Earth perpendicular to the equator line, this would be better. [[Special:Contributions/172.68.62.238|172.68.62.238]] 22:10, 18 December 2017 (UTC)CBM<br />
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:I agree with the comment above; the Earth's axis is always tilted 23 degrees from the plane of the orbit. There are times the North pole is tilted toward the Sun and times it is tilted away from the Sun. Twice a year (at the equinoxes) the tilt is perpendicular to the Sun. [[Special:Contributions/108.162.221.239|108.162.221.239]] 22:47, 18 December 2017 (UTC)<br />
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:I've edited the descriptions - do they look better now? [[Special:Contributions/162.158.126.28|162.158.126.28]] 00:32, 19 December 2017 (UTC)<br />
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;Daylight Saving Time<br />
Twice the description references locations that don't follow the common DST plan as 'other than the natural latitude would suggest'. The ''longitude'' would suggest a time zone, not the latitude. [[Special:Contributions/108.162.221.239|108.162.221.239]] 22:47, 18 December 2017 (UTC)<br />
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;Arbitrary decision by Benjamin Franklin<br />
The electric charge on an electron is conventionally described as being negative. I was always taught that this was because of a more or less arbitrary decision made by Franklin. I suspect Mr Munroe is humorously conflating this with Franklin's connection to Daylight Saving Time. <br />
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;Favorite combinations<br />
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My personal favorite: “Did you know that Toyota Truck Month happens at the wrong time every year because of a decree by the pope in the 1500s? Apparently it’s getting worse and no one knows why. While it may seem like trivia, it is now recognized as a major cause of World War 1. [[User:PotatoGod|PotatoGod]] ([[User talk:PotatoGod|talk]]) 02:06, 19 December 2017 (UTC)<br />
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Got this from the link to the fact generator, and I like that too, maybe because it is close to the one above, which I first saw now:<br />
:Calendar Facts by xkcd<br />
:Did you know that Shark Week drifts out of sync with the sun because of a decree by the pope in the 1500s?<br />
:Apparently it's getting worse and no one knows why.<br />
:While it may seem like trivia, it triggered the 2003 Northeast Blackout.<br />
Damn sharks and pope decree. --[[User:Kynde|Kynde]] ([[User talk:Kynde|talk]]) 10:08, 19 December 2017 (UTC)<br />
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"Did you know that Shark Week might happen twice this year because of..." Sold. Don't care about the rest. [[Special:Contributions/172.68.34.64|172.68.34.64]] 23:28, 20 December 2017 (UTC)<br />
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Is no one going to mention that "Shark Week" sometimes is used as slang to refer to menstruation? That's what I thought of the moment I saw it, and since cycles are roughly every 28 days but can change length slowly to re-synchronize (with others or for various reasons) that might be another valid interpretation. [[Special:Contributions/172.69.22.86|172.69.22.86]] 20:14, 31 December 2017 (UTC)Rowan<br />
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What's incomplete in this explanation? Seems pretty exhaustive to me. Can't we remove the incomplete tag? Zetfr 15:09, 2 May 2018 (UTC)</div>198.41.238.82https://www.explainxkcd.com/wiki/index.php?title=2034:_Equations&diff=1613302034: Equations2018-08-17T08:32:11Z<p>198.41.238.82: /* Explanation */</p>
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<div>{{comic<br />
| number = 2034<br />
| date = August 17, 2018<br />
| title = Equations<br />
| image = equations.png<br />
| titletext = All electromagnetic equations: The same as all fluid dynamics equations, but with the 8 and 23 replaced with the permittivity and permeability of free , respectively.<br />
}}<br />
<br />
==Explanation==<br />
{{incomplete|Created by an EQUATION - Please change this comment when editing this page. Do NOT delete this tag too soon.}}<br />
{| class="wikitable"<br />
!style="width:20%"|Equation<br />
!style="width:20%"|Field<br />
!style="width:60%"|Explanation<br />
|-<br />
|<math>E = K_0t + \frac{1}{2}\rho vt^2</math><br />
|All kinematics equations<br />
|Energy equals a constant <math>K_0</math> multiplied by time plus half of density multiplied by speed multiplied by time squared<br />
|-<br />
|<math>K_n = \sum_{i=0}^{\infty}\sum_{\pi=0}^{\infty}(n-\pi)(i-e^{\pi-\infty})</math><br />
|All number theory equations<br />
|Taken literal the equation says: "The nth K-number is equal to for all i in 0 to infinity, for all pi in 0 to infinity; subtract pi from n and multiply it with i minus e (to the power of pi minus infinity)". A twofold misconception can be seen here. The first is the reassignment of pi as a variable instead of the constant (3.14). This might be a jab at how in number theory letters and numbers are used interchangeably, but where some letters are all of a sudden fixed constants. The second misconception is the use of infinity in the latter part of the formula. Naively this would signify that (with the reassigned pi values) the part in the power would range from minus infinity to zero. However infinity is not a number and cannot be used as one without using a limit construct.<br />
|-<br />
|<math>\frac{\partial}{\partial t}\nabla\cdot p = \frac{8}{23}<br />
<br />
\int\!\!\!\!\!\!\!\!\!\;\;\bigcirc\!\!\!\!\!\!\!\!\!\;\;\int<br />
\rho\,ds\,dt\cdot \rho\frac{\partial}{\partial\nabla}<br />
</math><br />
|All fluid dynamic equations<br />
|-<br />
|<math>|\psi_{x,y}\rangle = A(\psi) A(|x\rangle \otimes |y\rangle)</math><br />
|All quantum mechanic equations<br />
|<br />
|-<br />
|<math>\mathrm{CH}_4 + \mathrm{OH} + \mathrm{HEAT} \rightarrow \mathrm{H}_2\mathrm{O} + \mathrm{CH}_2 + \mathrm{H}_2 \mathrm{EAT}</math><br />
|All chemistry equations<br />
| A modification of the combustion of methane. The correct form is often taught and a good example problem but obviously there are more chemistry problems.<math>HEAT</math> is normally shorthand for {{w|activation energy}}, but in Randall's version it's jokingly used as a chemical ingredient and becomes <math>H_2EAT</math>, taking the hydrogen atom freed by the combustion equation shown. To deliver the punchline while maintaining proper stoichiometry, <math>\mathrm{OH}</math> (which should be <math>\mathrm{OH}^-</math>, since the oxygen keeps a free electron when it combines with a single hydrogen) is shown instead of <math>\mathrm{O}_2</math>. The proper methane combustion equation would be: <math>\mathrm{CH}_4 + 2 \mathrm{O}_2 \rightarrow 2 \mathrm{H}_2\mathrm{O} + \mathrm{CO}_2</math><br />
|-<br />
|<math>SU(2)U(1) \times SU\left(U(2)\right)</math><br />
|All quantum gravity equations<br />
|<br />
|-<br />
|<math>S_g = \frac{-1}{2\bar{\epsilon}}i\eth \hat{\big(} \zeta_0 \dotplus p_\epsilon \rho_v^{abc}\cdot \eta_0 \hat{\big)} f_a^0 a\lambda(\xi) \psi(0_a)</math><br><br />
|All gauge theory equations<br />
|<br />
|-<br />
|<math>H(t) + \Omega + G \cdot \Lambda \, \dots \begin{cases} \dots > 0 & \text{(HUBBLE MODEL)} \\ \dots = 0 & \text{(FLAT SPHERE MODEL)} \\ \dots < 0 & \text{(BRIGHT DARK MATTER MODEL)} \end{cases}<br />
</math><br />
|All cosmology equations<br />
|<br />
|-<br />
|<math>\hat H - u_{0} = 0</math><br />
|All truly deep physics equations<br />
|<br />
|<math>\hat H</math> it the hamiltonian operator which is the operator which wen applied to a system returns the total energy. In this context U would usually be the potential energy. However there is also a subscript 0 and a diacritic making indicating some other variable. Much of physics is based on Lagrangian and Hamiltonian mechanics the Lagrangian is defined as <math>\hat L = \hat K - \hat U </math> with K being the kinetic energy and U the potential. Hamiltonian mechanics uses the equation <math>\hat H = \hat K + \hat U </math>. the Hamiltonian mus be conserved so taking the time derivative and setting it equal to zero is a powerful tool. The principle of least action says allows most modern physics to be derived by setting the time derivative of the lagrangian to zero.<br />
|<math>\frac{\partial}{\partial t}\nabla\cdot p = \frac{\epsilon_0}{\mu_0}<br />
\int\!\!\!\!\!\!\!\!\!\;\;\bigcirc\!\!\!\!\!\!\!\!\!\;\;\int<br />
\rho\,ds\,dt\cdot \rho\frac{\partial}{\partial\nabla}<br />
</math><br />
|All electromagnetic equations<br />
|This equation has superficial resemblance to portions of [//en.wikipedia.org/wiki/Maxwell%27s_equations Maxwell's Equations], but just miscellaneous bits, some from the integral forms and some from the differential forms.<br />
|}<br />
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==Transcript==<br />
{{incomplete transcript|Do NOT delete this tag too soon.}}<br />
[TODO: Avoid using math markup here because the images of these equations isn't helpful in a transcript. Sigh.]<br />
[Nine equations are listed and labeled as followed:]<br />
<br><br><br />
E = K<sub>0</sub>t + 1/2 pvt<sup>2</sup><br><br />
ALL KINEMATICS EQUATIONS<br><br />
<br><br />
<math>K_n = \sum_{i=0}^{\infty}\sum_{\pi=0}^{\infty}(n-\pi)(i-e^{\pi-\infty})</math><br><br />
ALL NUMBER THEORY EQUATIONS<br><br />
<br><br />
&#x2202;/&#x2202;t &nabla; &sdot; p = 8/23 (&#x222F; &rho; ds dt &sdot; &rho; &#x2202;/&#x2202;&nabla;)<br><br />
ALL FLUID DYNAMIC EQUATIONS<br><br />
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<math>|\psi_{x,y}\rangle = A(\psi) A(|x\rangle \otimes |y\rangle)</math><br><br />
ALL QUANTUM MECHANIC EQUATIONS<br><br />
<br><br />
CH<sub>4</sub> + OH + HEAT &rarr; H<sub>2</sub>O + CH<sub>2</sub> + H<sub>2</sub>EAT <br><br />
ALL CHEMISTRY EQUATIONS<br><br />
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SU(2)U(1) &times; SU(U(2)) <br><br />
ALL QUANTUM GRAVITY EQUATIONS<br><br />
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<math>S_g = \frac{-1}{2\epsilon}i\eth \hat{\big(} \zeta_0 \dotplus p_\epsilon \rho_v^{abc}\cdot \eta_0 \hat{\big)} f_a^0 a\lambda(\zeta) \psi(0_a)</math><br><br />
ALL GAUGE THEORY EQUATIONS<br><br />
<br><br />
<math>H(t) + \Omega + G \cdot \land \, ... \begin{cases} ... > 0 & \text{(HUBBLE MODEL)} \\ ... = 0 & \text{(FLAT SPHERE MODEL)} \\ ... < 0 & \text{(BRIGHT DARK MATTER MODEL)} \end{cases}<br />
</math><br><br />
ALL COSMOLOGY EQUATIONS<br><br />
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&#x0124; - u̧<sub>0</sub> = 0<br><br />
ALL TRULY DEEP PHYSICS EQUATIONS<br />
<br><br />
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{{comic discussion}}<br />
[[Category:Math]]</div>198.41.238.82