https://www.explainxkcd.com/wiki/api.php?action=feedcontributions&user=173.245.52.27&feedformat=atomexplain xkcd - User contributions [en]2024-03-28T09:34:02ZUser contributionsMediaWiki 1.30.0https://www.explainxkcd.com/wiki/index.php?title=Talk:1644:_Stargazing&diff=112504Talk:1644: Stargazing2016-02-18T08:02:53Z<p>173.245.52.27: </p>
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<div>?.. is this Brian Cox??? [[Special:Contributions/162.158.152.155|162.158.152.155]] 06:07, 17 February 2016 (UTC)<br />
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My first thought was that it was a pisstake of Brian Cox, except I wasn't sure if they had Stargazing Live in America. [[Special:Contributions/162.158.152.143|162.158.152.143]] 08:33, 17 February 2016 (UTC)<br />
: Brian Cox seems like a nice guy and I applaud his enthusiasm, but if you want to see a truly awesome science broadcaster look for a set of broadcasts from the 70s/80s by James Burke titled "The Day the Universe Changed", Mr. Cox's programmes seem to be as much about how many airmiles the production team can accumulate as they are about the science. [[Special:Contributions/162.158.34.147|162.158.34.147]] 09:10, 17 February 2016 (UTC)<br />
:: The airmiles comment above applies to Cox's "Wonders Of The Universe" series, certainly, but my first thought was either that Randall knew of the BBC's semi-regular programme-cluster "{{w|Stargazing Live}}", here in the UK, that Cox co-presents - perhaps via BBC America? - or else there's an equivalent US version (precursor or postcursor) of the same name that perhaps has a celebrity-based core team.<br />
:: (Brian's primary co-host in the programme ''is'' an Irish comedian, but one with a accredited science background who knows what they're talking about. They also have 'guest celebrities' for internal and external segments (from just outside the studio, under the night sky, to a pieces filmed/livecast at some space-relevant location, usually featured across all episodes of that season as a theme so not so much 'gratuitous globe-trotting) but they are all ''interested'' in space-stuff, and many ''also'' have an actual background expertise in physics/astronomy even if that's not what they're publicly known for.)<br />
:: Quickly looking around, I can't see any ''obvious'' astronomy programmes(/programs!) in the US that aren't similarly expert-led, but that's possibly because any that are don't feature as 'proper' programmes on any of the lists I've checked. [[Special:Contributions/162.158.152.89|162.158.152.89]] 14:25, 17 February 2016 (UTC)<br />
:: The title text does imply it is in reference to Brian Cox. He is well known for his very philosophical comments referencing physics in that way. [[Special:Contributions/141.101.70.151|141.101.70.151]] 20:05, 17 February 2016 (UTC)<br />
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I also thought this might be poking fun at the "Celebrity" presenters of TV astronomy programs. [[Special:Contributions/141.101.106.173|141.101.106.173]] 13:16, 17 February 2016 (UTC)<br />
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I believe the title text may be referring to the fact that several people think that the sun is the brightest star simply because it's the closest to us, completely disregarding absolute magnitude? I'd change the explanation if I knew how. --[[Special:Contributions/108.162.245.181|108.162.245.181]] 06:39, 17 February 2016 (UTC)<br />
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The original statement in the comic is about which star is the brightest *in our sky*, i.e. most visible radiation per square meter hitting Earth, not the star with the most total radiation. You can change the explanation just by hitting the little edit button to the top right of the "Explanation" section.<br />
[[Special:Contributions/108.162.237.91|108.162.237.91]] 06:57, 17 February 2016 (UTC)<br />
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I still don't get the main comic, unless its just situational comedy of someone acting like they know what they are talking about, when really they don't even know the meaning of the word "astronomer". [[Special:Contributions/108.162.237.91|108.162.237.91]] 07:01, 17 February 2016 (UTC)<br />
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I put my best understanding of the comic in the explanation - I'm not sure I really get it, but I figured it was better than nothing. [[Special:Contributions/108.162.237.91|108.162.237.91]] 07:14, 17 February 2016 (UTC)<br />
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This is exactly how I feel about looking at stars and hard core astronomy. I look for the brightest stars, and would like to know something about them, but just the basic facts. I have had a course on astronomy and it was boring to do the math for star formation and cosmology. I learnt that way that I was only interested in the results and conclusions, not in trying to calculate it my self, or counting all the other smaller stars to gain the data needed. I really like Megan here ;-) Space is awesome, astronomy is boring :-) --[[User:Kynde|Kynde]] ([[User talk:Kynde|talk]]) 09:08, 17 February 2016 (UTC)<br />
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I am pretty sure the last line in the first panel used to read "I'm doctor '''of''' whatever", but now it's clearly "... doctor '''or''' whatever". Has Randall changed the comic? -- [[Special:Contributions/141.101.106.11|141.101.106.11]] 13:06, 17 February 2016 (UTC)<br />
:I wrote the original transcript based on the comic on this site. This has since been corrected to or, which makes sense. But the image file for the comic has not been changed here on xkcd, so had it not been for your comment here, I would just have put it down to a typo on my behalf. I still think so, as I believed she said ''or whatever'' when I wrote about it in the explanation. But the "or" can look a little as "of". It is, however, not unheard of that Randall changes a comic if he spots a mistake after the first release. This has happened several times. --[[User:Kynde|Kynde]] ([[User talk:Kynde|talk]]) 14:50, 17 February 2016 (UTC)<br />
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From now on I plan to present Sirius as the brightest star that can be seen at night, just to take the wind out of the jokers sails... [[User:Andyd273|Andyd273]] ([[User talk:Andyd273|talk]]) 14:34, 17 February 2016 (UTC)<br />
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I wonder if the style of speaking is a reference to Donald Trump.<br />
[[Special:Contributions/108.162.237.90|108.162.237.90]] 19:31, 17 February 2016 (UTC)<br />
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She'd reminding me an awful lot of [[Beret Guy]] here, kind of scattered and . Is it just me? [[User:N0lqu|-boB]] ([[User talk:N0lqu|talk]]) 20:42, 17 February 2016 (UTC)<br />
:It's not just you... and from that point of view the title text doesn't read like sarcasm to me. Perhaps more a reference to choosing branches of science to explore? Then again, at least one person thought it was sarcastic, and I don't feel strongly enough to change the explanation over it. [[Special:Contributions/108.162.250.161|108.162.250.161]] 01:35, 18 February 2016 (UTC)<br />
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Not true there is nothing in interstellar space. Dust, vacuum, photons, even heat energy. 08:02, 18 February 2016 (UTC)</div>173.245.52.27https://www.explainxkcd.com/wiki/index.php?title=Talk:247:_Factoring_the_Time&diff=109527Talk:247: Factoring the Time2016-01-20T06:23:41Z<p>173.245.52.27: </p>
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<div>I used to find the prime factors of the remaining distance until the next turn. It starts off difficult (for me) at 99 miles, etc. When it gets down to 30 miles, it gets easier. Then, at 9.9 miles, I have a tenth the time to factor 99 again, and it gets easier as the numbers get smaller. This is actually a pretty good way to pass the time while driving. {{unsigned ip|108.162.219.202}}<br />
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Paying attention to your driving might be a benefit. To yourself and others. Just sayin'.[[User:Jakee308|Jakee308]] ([[User talk:Jakee308|talk]]) 20:00, 24 April 2015 (UTC)<br />
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I wonder how much time Randall spent trying to find a time that is not prime but the time + 1200 would be. {{unsigned|Flewk}}<br />
:Took me about 5 minutes with a script after getting a list of primes from the internet: 1:19; 1:21; 2:09; 2:47; 2:53; 2:59; 3:23; 3:43; 4:07; 4:13; 4:27; 4:37; 5:33; 5:53; 5:59; 6:11; 6:23; 7:07; 7:13; 7:31; 7:49; 8:03; 8:17; 9:13; 9:31; 9:43; 10:03; 10:07; 10:37; 10:43; 11:11; 11:33; 11:39; 11:41; 11:47; 11:57 (also the technical cases of: 12:03; 12:05; 12:07; 12:11; 12:19; 12:41; 12:43; 12:47; 12:53) . --[[Special:Contributions/173.245.52.27|173.245.52.27]] 06:18, 20 January 2016 (UTC)</div>173.245.52.27https://www.explainxkcd.com/wiki/index.php?title=Talk:247:_Factoring_the_Time&diff=109526Talk:247: Factoring the Time2016-01-20T06:18:51Z<p>173.245.52.27: </p>
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<div>I used to find the prime factors of the remaining distance until the next turn. It starts off difficult (for me) at 99 miles, etc. When it gets down to 30 miles, it gets easier. Then, at 9.9 miles, I have a tenth the time to factor 99 again, and it gets easier as the numbers get smaller. This is actually a pretty good way to pass the time while driving. {{unsigned ip|108.162.219.202}}<br />
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Paying attention to your driving might be a benefit. To yourself and others. Just sayin'.[[User:Jakee308|Jakee308]] ([[User talk:Jakee308|talk]]) 20:00, 24 April 2015 (UTC)<br />
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I wonder how much time Randall spent trying to find a time that is not prime but the time + 1200 would be. {{unsigned|Flewk}}<br />
:Took me about 5 minutes with a script after getting a list of primes from the internet: 1:19; 1:21; 2:09; 2:47; 2:53; 2:59; 3:23; 3:43; 4:07; 4:13; 4:27; 4:37; 5:33; 5:53; 5:59; 6:11; 6:23; 7:07; 7:13; 7:31; 7:49; 8:03; 8:17; 9:13; 9:31; 9:43; 10:03; 10:07; 10:37; 10:43; 11:11; 11:33; 11:39; 11:41; 11:47; 11:57 (ignoring times between between 12AM and 1AM, as going to 24 hour time would make it easier). --[[Special:Contributions/173.245.52.27|173.245.52.27]] 06:18, 20 January 2016 (UTC)</div>173.245.52.27https://www.explainxkcd.com/wiki/index.php?title=Talk:991:_Phantom_Menace&diff=107188Talk:991: Phantom Menace2015-12-17T22:34:24Z<p>173.245.52.27: </p>
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<div>Episode I is so much maligned that some fans have created their own viewing order:<br />
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*IV: A New Hope<br />
*V: The Empire Strikes Back<br />
*II: Attack of the Clones<br />
*III: Revenge of the Sith<br />
*VI: Return of the Jedi<br />
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Skipping The Pantom Menace entirely. [http://www.nomachetejuggling.com/2011/11/11/the-star-wars-saga-suggested-viewing-order/] <br />
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[[User:Lcarsos|lcarsos]] ([[User talk:Lcarsos|talk]]) 23:26, 28 August 2012 (UTC)<br />
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I like to believe that being in line early is a phantom menace.--[[User:Shine|Shine]] ([[User talk:Shine|talk]]) 05:37, 2 March 2013 (UTC)<br />
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I actually saw the 3D rerelease... [[User:BlueDudeWithATude|BlueDudeWithATude]] ([[User talk:BlueDudeWithATude|talk]]) 15:43, 27 May 2013 (UTC)<br />
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I think that the existing explanation kind of misses the comic entirely. The comic was published 2 months before the 3D rerelease, so we can assume that the events of the comic take place at the same time as the publishing and so the characters are standing there at least 2 months early. Also, Cueball says "Let's give it one more month" to the suggestion that they aren't even in line for a theatre, suggesting that a) they've probably been waiting for at least a month, and b) they're so dedicated that they went to watch the movie without even knowing where they were going. So, my explanation would be that the characters are die-hard Star Wars fans, willing to watch even the much-maligned Episode I and also convinced of the sheer importance of this event that they're willing to line up at least 3 months in advance at what might not even be a theatre. [[User:Gman314|Gman314]] ([[User talk:Gman314|talk]]) 16:57, 16 August 2013 (UTC)<br />
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I'm reasonably certain (but not so certain as to edit the article) that the joke is not that they're waiting for the re-release of Phantom Menace in 2012, but the original release in 1999. [[User:Neito|Neito]] ([[User talk:Neito|talk]]) 02:50, 17 December 2013 (UTC)<br />
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The intent of the comic is identical either way, and there are no clues to help us decide, except for the timing of publication. They both seem pretty clueless; the terrible props, the inane conversation, and the simple fact that they have been in line *by themselves* for a long time, with no clear indication that they are even at a theater. Is Randall trying to say that people queuing up to see phantom menace, are, to put it bluntly, stupid? [[Special:Contributions/108.162.219.223|108.162.219.223]] 22:40, 21 January 2014 (UTC)<br />
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The first time I read this, without reading the explanation, I thought that they want to be the first to see the movie, even going as far as waiting for an abandoned building to become a theater. This way, they guarantee that they will be the first in line when the theater opens. [[Special:Contributions/141.101.99.245|141.101.99.245]] 04:03, 28 January 2014 (UTC)<br />
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Wait!<br />
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They weren't?<br />
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Oh wait... IDGAF! (I forgot.)<br />
[[User:Weatherlawyer| I used Google News BEFORE it was clickbait]] ([[User talk:Weatherlawyer|talk]]) 07:28, 22 January 2015 (UTC)<br />
This is me with star wars 7 [[Special:Contributions/173.245.52.27|173.245.52.27]] 22:34, 17 December 2015 (UTC)</div>173.245.52.27https://www.explainxkcd.com/wiki/index.php?title=975:_Occulting_Telescope&diff=106755975: Occulting Telescope2015-12-11T01:22:15Z<p>173.245.52.27: Corrected defintion, removed opinionated content.</p>
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<div>{{comic<br />
| number = 975<br />
| date = November 09, 2011<br />
| title = Occulting Telescope<br />
| image = occulting_telescope.png<br />
| titletext = Type II Kardashev civilizations eventually completely enclose their planetary system in a Dyson sphere because space is way too big to look at all the time.<br />
}}<br />
<br />
==Explanation==<br />
[[File:Dyson Swarm.png|thumb|A relatively simple arrangement of multiple Dyson Rings of the type pictured above, to form a more complex Dyson Swarm. Rings' orbital radii are spaced 1.5 x 10^7 km with regard to one another, but average orbital radius is still 1 {{w|Astronomical unit|AU}}. Rings are rotated 15 degrees relative to one another, around a common axis of rotation. (from Wikipedia Commons)]]<br />
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[[Cueball]] takes the useful practice of {{w|occulting}} stars beyond its intended purpose. Occulting is used to block the light from a star under observation so that adjacent dim objects, such as any {{w|extrasolar planets|surrounding planets}}, might be more easily detected and examined. Instead of blocking the light of a single star for the purposes of observation, Cueball proposes blocking the light from all stars, for the purpose of making him feel comfortable with the night sky. Cueball feels, some might say irrationally, that "there are too many stars, and it's been ''freaking me out''".<br />
<br />
The title text refers to both a {{w|Kardashev scale|Type II Kardashev civilization}} and a {{w|Dyson sphere}}.<br />
<br />
A Dyson sphere is a theoretical construction consisting of a network of satellites that orbit and completely surround a star. The purpose to capture and transmit all of the available solar energy back to a planet.<br />
<br />
A Type II Kardashev civilization is a theoretical civilization that has advanced to the point where it has harnessed the energy radiated by its own star (for example, the stage of successful construction of a Dyson sphere).<br />
<br />
For comparison purposes:<br />
*A Type I Kardashev civilization is one that has harnessed the energy of their entire planet.<br />
*A Type III Kardashev civilization is one that has harnessed the energy of their entire galaxy.<br />
*We are currently less than I.<br />
<br />
The title text reveals that Type II Kardashev civilizations construct Dyson spheres not for the purposes of capturing all solar energy, but merely to block the view of all that hideous space.<br />
<br />
==Transcript==<br />
:[Cueball is giving a lecture in front of a white board, pointing to a diagram with a pointer.]<br />
:Cueball: The occulting observatory consists of two parts—the telescope and the discs.<br />
<br />
:When the telescope sees a star, a disc is carefully steered to block its light.<br />
:[A diagram of a satellite labeled "telescope" with waves going from it on the left, across to the other side of the diagram (labeled "light from star") on the right. In the middle is a small vertical line labeled "disc", stopping some of the light waves from the right traveling to the left of the diagram.]<br />
:This procedure is repeated until all stars are covered.<br />
<br />
:[Cueball looks down at a student.]<br />
:Student (off screen): Wait, all? Why?<br />
:Cueball: I'll feel better.<br />
<br />
:[Close-up on Cueball.]<br />
:Student (off-screen): I thought the point was to image extrasolar planets.<br />
:Cueball: The point is that there are ''too many stars.'' It's been freaking me out.<br />
:Student: What?<br />
:Student #2 (in smaller letters): He has a point...<br />
<br />
{{comic discussion}}<br />
[[Category:Comics featuring Cueball]]<br />
[[Category:Astronomy]]<br />
[[Category:Exoplanets]]</div>173.245.52.27https://www.explainxkcd.com/wiki/index.php?title=1547:_Solar_System_Questions&diff=970701547: Solar System Questions2015-07-06T19:37:03Z<p>173.245.52.27: "build" -> "built"</p>
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<div>{{comic<br />
| number = 1547<br />
| date = July 6, 2015<br />
| title = Solar System Questions<br />
| image = solar_system_questions.png<br />
| titletext = My country's World Cup win was exciting and all, but c'mon, what if the players wore nylon wings and COULD LITERALLY FLY?<br />
}}<br />
<br />
==Explanation==<br />
{{incomplete|Created by a BOT - single answer then added by a human.}}<br />
<br />
This comic is a list of questions which Randall has about the Solar System, which at first glance may appear to be things that Randall would like to learn about.<br />
In actual fact most of the questions have not been satisfactorily answered or proven by anyone in the scientific community.<br />
<br />
{| class="wikitable"<br />
|-<br />
! Question given<br />
! Answer given by Randall (in Red)<br />
! Comments<br />
|-<br />
| Why is the the Moon so blotchy?<br />
| Lava<br />
| "the the" could be a Randallism (intended or unintended).<br />
|-<br />
| Why are all the blotches on the near side?<br />
| ...<br />
| The nearside of the Moon is dominated by the blotchy 'seas' (volcanic flats), the far side by craters. Possibly an overabundance of craters obliterate the blotches, and the far side was always more 'exposed' to impacts.<br />
|-<br />
| Did Mars have seas?<br />
| Yes (briefly?)<br />
| Recent explorations have confirmed there was once standing water (not just occasional flowing water), but not yet how long, save that it created the sedimentary layers that we have seen.<br />
|-<br />
| Was there life on Mars?<br />
| ...<br />
| One of the big mysteries, not yet answered.<br />
|-<br />
| What's Titan like?<br />
| Cold, yellow, lakes + rivers (methane)<br />
| <br />
|-<br />
| What was Earth like during the Hadean?<br />
| ...<br />
| {{w|Hadean}}<br />
|-<br />
| Is the Oort Cloud a real thing?<br />
| ...<br />
| The {{w|Oort Cloud}} is a theoretical spherical cloud of icy planetsimals centred around our sun.<br />
|-<br />
| Why is the Sun's corona so hot?<br />
| Something about magnets?<br />
| The {{w|corona}} of the sun is hotter than it theoretically should be. The looping magnetic fields in this area could be responsible.<br />
|-<br />
| What are comets like?<br />
| Precipitous<br />
| The {{w|Philae (spacecraft)|Philae lander}} is next to a cliff...<br />
|-<br />
| Where's Philae, exactly?<br />
| ...<br />
| ...but we're not sure ''which'' cliff.<br />
|-<br />
| What's Pluto like?<br />
| rowspan="2" | [Soon!]<br />
| rowspan="2" | The probe {{w|New Horizons}} may be about to answer both of these questions.<br />
|-<br />
| What's Charon like?<br />
|-<br />
| Why don't we have in-between-sized planets?<br />
| ...<br />
| There is a size-gap between the rocky planets (up to Earth size) and the gas giants<br />
|-<br />
| What's Ceres like?<br />
| [Working on it!]<br />
| Another probe, {{w|Dawn (spacecraft)}}.<br />
|-<br />
| Why is Europa so weird-looking and pretty?<br />
| Ice over a water ocean<br />
| <br />
|-<br />
| Why is Io so weird-looking?<br />
| Sulfur volcanoes (? in the wrong places?)<br />
| <br />
|-<br />
| Why are so many Kuiper Belt objects red?<br />
| ...<br />
| Many objects in the {{w|Kuiper Belt}} have a reddish hue. A possible explanation is that they are [http://www.space.com/9418-icy-red-objects-solar-system-edge-point-life-building-blocks.html| covered in organic molecules] formed by the irradiation of their surface ices. The {{w|New Horizons}} probe might also shed light on this.<br />
|-<br />
| What are those spots on Ceres?<br />
| ...<br />
| {{w|Ceres (dwarf planet)|Ceres}}<br />
|-<br />
| What's in the seas under Europa's ice?<br />
| ...<br />
| {{w|Europa (moon)|Europa}}<br />
|-<br />
| Which of the other moons have seas?<br />
| Several<br />
| (Partial/initial list possible? Definition of 'seas' would affect this.)<br />
|-<br />
| What are the big white things in Titan's Lakes?<br />
| ...<br />
| {{w|Lakes of Titan}}<br />
|-<br />
| What do Jupiter's clouds look like up close?<br />
| ...<br />
| <br />
|-<br />
| What's all that red stuff in the Great Red Spot?<br />
| ...<br />
| <br />
|-<br />
| What's pushing the Pioneer Probes?<br />
| Heat from the RTG<br />
| Discussed as the {{w|Pioneer anomaly}}. RTG stands for {{w|Radioisotope Thermoelectric Generator}}.<br />
|-<br />
| What pushes spacecraft slightly during flybys?<br />
| ...<br />
| The related {{w|Flyby anomaly}}.<br />
|-<br />
| Where are all the Sun's Neutrinos?<br />
| Oscillating<br />
| {{w|Solar neutrino problem}}<br />
|-<br />
| Why is there so much air on Titan?<br />
| ...<br />
| <br />
|-<br />
| Why does the Kuiper Belt Stop?<br />
| ...<br />
| A reference to the {{w|Kuiper Cliff}}.<br />
|-<br />
| Why is Iapetus weird-colored?<br />
| ...<br />
| <br />
|-<br />
| Why does Iapetus have a belt?<br />
| ...<br />
| <br />
|-<br />
| What's the deal with Miranda?<br />
| ...<br />
| {{w|Miranda_(moon)|Miranda}} is the smallest of Uranus's five round satellites. Also possibly a [[Firefly|''Firefly'' reference]] since {{w|https://en.wikipedia.org/wiki/List_of_Firefly_planets_and_moons#Miranda|Miranda}} is the name of a planet in {{w|https://en.wikipedia.org/wiki/Serenity_(film)|''Serenity''}}, a film in the {{w|https://en.wikipedia.org/wiki/Firefly_(TV_series)|''Firefly''}} series.<br />
|-<br />
| Did Uranus and Neptune change places?<br />
| ...<br />
| The {{w|Nice model}} is a theory of how our solar system formed, which suggested the possibility of Uranus and Neptune having swapped places before reaching their current positions. Work by Professor S. Desch [http://dusty.la.asu.edu/~desch/publications/2007/Desch2007.pdf| also came to this result].<br />
|-<br />
| Did the Late Heavy Bombardment happen?<br />
| ...<br />
| <br />
|-<br />
| Did life start before it?<br />
| ...<br />
| <br />
|-<br />
| Is Europa covered in Ice Spikes?<br />
| ...<br />
| <br />
|-<br />
| Why haven't we built a big inflatable Extreme Sports Complex on The Moon?<br />
| ...<br />
| See, e.g., ''{{w|The Menace From Earth}}'', a 1957 short story by Robert Heinlein.<br />
| <br />
|-<br />
| (Titletext) My country's World Cup win was exciting and all, but c'mon, what if the players wore nylon wings and COULD LITERALLY FLY?<br />
| ...<br />
| {{w|2015 FIFA Women's World Cup}}<br />
|}<br />
<br />
==Transcript==<br />
{{incomplete transcript}}<br />
<br />
{{comic discussion}}<br />
<br />
[[Category:Firefly]]</div>173.245.52.27https://www.explainxkcd.com/wiki/index.php?title=1377:_Fish&diff=689221377: Fish2014-06-05T17:51:11Z<p>173.245.52.27: /* Explanation */ "Lift on Earth" => "Life on Earth"</p>
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<div>{{comic<br />
| number = 1377<br />
| date = June 4, 2014<br />
| title = Fish<br />
| image = fish.png<br />
| titletext = [Astronomer peers into telescope] [Jaws theme begins playing]<br />
}}<br />
<br />
==Explanation==<br />
The {{w|Fermi Paradox}} is the contradiction that arises between the high likelihood of {{w|extraterrestial life}} and the fact that no evidence for it has thus far been found. <br />
<br />
[[Cueball]] and [[Megan]] are having a conversation regarding this — since new planets are found all the time around distant stars, Cueball comments that this makes it an even greater paradox. Megan suggests that perhaps our search for extraterrestrial life is like looking at a patch of ocean floor looking for a fish. The diver knows that there must be a fish somewhere, but is unable to actually find it. She then goes on to ask why the fish would be hidden — i.e. camouflaged, and what it means about the remaining fish. The suggestion is that the fish would be hidden to avoid being eaten by predators, and perhaps the reason no extraterrestrial life is sending any sign of existence back is that they fear they might be destroyed soon after they revealed their location. Maybe they have even actively tried to hide the presence of their entire planet if they obtain the technological means. This potentially refers to the Deadly Probes scenario.<br />
<br />
The camouflaged fish could be identified by using more sophisticated technologies like infrared cameras. Looking at the Earth from space beyond {{w|Low Earth orbit}} only with the naked eye wouldn't show any hint to our {{w|ecosystem}}. This is like the actual possibility in astronomy when observing {{w|Exoplanet|exoplanets}} — the nature of those more than 1,500 known planets is unknown due to the lack of better technologies to the scientists. And there are a couple of hundred Billion planets at our galaxy still camouflaged to human scientists.<br />
<br />
The final panels take the metaphor further, suggesting that there is literally a planet sized shark swimming through space eating planets, and since the view is panning away from earth and over to the shark, the shark seems to be heading our way... So it looks like Earth is the next fish, presumably because we did not reach a high enough technology level in time to recognize the danger and hide.<br />
<br />
This also explains the title text that has the theme from the movie ''{{w|Jaws (film)|Jaws}}'' playing while astronomers look into their telescopes. This may also be a reference to the film ''{{w|Alien (film)|Alien}}'', which was pitched with the three word proposal "''Jaws'' in Space."<br />
<br />
<br />
{{w|Stephen Hawking}} famously warns, “If aliens visit us, the outcome would be much as when Columbus landed in America, which didn’t turn out well for the Native Americans.”. Even {{w|Carl Sagan}} called the practice of Broadcasting and Signaling presence of Life on Earth “deeply unwise and immature,” and recommended that “the newest children in a strange and uncertain cosmos should listen quietly for a long time, patiently learning about the universe and comparing notes, before shouting into an unknown jungle that we do not understand.”<br />
<br />
==Transcript==<br />
:[Cueball and Megan are walking down a hill.]<br />
:Cueball: The Fermi paradox keeps getting worse. If planets are common, where '''is''' everybody?<br />
<br />
:Megan: Imagine you're a scuba diver looking at the ocean floor. You know there's a fish there, but you can't see it. Why?<br />
<br />
:Cueball: Maybe the fish looks like sand.<br />
:Megan: Yeah...<br />
<br />
:[Zoom out to the Earth from space.]<br />
:Megan: ...and what would that tell you about the ecosystem?<br />
<br />
:[The Earth is moving out of the panel and then a shark is shown swimming through space towards Earth.]<br />
<br />
{{comic discussion}}<br />
<br />
[[Category:Comics featuring Cueball]]<br />
[[Category:Comics featuring Megan]]<br />
[[Category:Astronomy]]<br />
[[Category:Science]]<br />
[[Category:Sharks]]</div>173.245.52.27https://www.explainxkcd.com/wiki/index.php?title=Talk:1369:_TMI&diff=67404Talk:1369: TMI2014-05-16T08:55:40Z<p>173.245.52.27: signature</p>
<hr />
<div>I assume "TMI" here stands for "too much information". Cueball stares at the screen (presumably with an Internet browser open) and realizes that he will never be able to internalize the amounts of data freely available on the net. The off-screen voice simply confirms it. The humor of the exchange seems to be derived from the fact that "too much information" is usually used to indicate that someone has publicly given away too much ''private'' and potentially embarrassing information and made others feel awkward. Cueball, however, uses the phrase in its most literal sense. --[[User:Koveras|Koveras]] ([[User talk:Koveras|talk]]) 06:47, 16 May 2014 (UTC)<br />
<br />
TMI is probably {{Wiktionary|too much information|Too Much Information}} (taken literally, not figuratively about ''overshare'') --[[User:JakubNarebski|JakubNarebski]] ([[User talk:JakubNarebski|talk]]) 06:49, 16 May 2014 (UTC)<br />
<br />
It could also refer to Three Mile Island; but 'Too Much Information' or 'Too Much Internet' are the most likely meanings. TMA! (Too Many Acronyms!) [[Special:Contributions/173.245.53.123|173.245.53.123]] 07:06, 16 May 2014 (UTC)<br />
<br />
The title text may be a reference to the quote from the Sherlock Holmes novel ''A Study in Scarlet'': "From a drop of water, a logician could infer the possibility of an Atlantic or a Niagara without having seen or heard of one or the other." If that logician stared into an entire sea worth of water drops, all the possible inferences would probably make his head explode from literally too much information. --[[User:Koveras|Koveras]] ([[User talk:Koveras|talk]]) 07:15, 16 May 2014 (UTC)<br />
<br />
Maybe ''Everything'' is litteraly just information, like in ''{{W|Decoding Reality}}''. [[Special:Contributions/173.245.52.27|173.245.52.27]] 08:55, 16 May 2014 (UTC)</div>173.245.52.27https://www.explainxkcd.com/wiki/index.php?title=Talk:1369:_TMI&diff=67403Talk:1369: TMI2014-05-16T08:54:13Z<p>173.245.52.27: Decoding Reality</p>
<hr />
<div>I assume "TMI" here stands for "too much information". Cueball stares at the screen (presumably with an Internet browser open) and realizes that he will never be able to internalize the amounts of data freely available on the net. The off-screen voice simply confirms it. The humor of the exchange seems to be derived from the fact that "too much information" is usually used to indicate that someone has publicly given away too much ''private'' and potentially embarrassing information and made others feel awkward. Cueball, however, uses the phrase in its most literal sense. --[[User:Koveras|Koveras]] ([[User talk:Koveras|talk]]) 06:47, 16 May 2014 (UTC)<br />
<br />
TMI is probably {{Wiktionary|too much information|Too Much Information}} (taken literally, not figuratively about ''overshare'') --[[User:JakubNarebski|JakubNarebski]] ([[User talk:JakubNarebski|talk]]) 06:49, 16 May 2014 (UTC)<br />
<br />
It could also refer to Three Mile Island; but 'Too Much Information' or 'Too Much Internet' are the most likely meanings. TMA! (Too Many Acronyms!) [[Special:Contributions/173.245.53.123|173.245.53.123]] 07:06, 16 May 2014 (UTC)<br />
<br />
The title text may be a reference to the quote from the Sherlock Holmes novel ''A Study in Scarlet'': "From a drop of water, a logician could infer the possibility of an Atlantic or a Niagara without having seen or heard of one or the other." If that logician stared into an entire sea worth of water drops, all the possible inferences would probably make his head explode from literally too much information. --[[User:Koveras|Koveras]] ([[User talk:Koveras|talk]]) 07:15, 16 May 2014 (UTC)<br />
<br />
Maybe ''Everything'' is litteraly just information, like in ''[http://en.wikipedia.org/wiki/Decoding_Reality Decoding Reality]''.</div>173.245.52.27https://www.explainxkcd.com/wiki/index.php?title=Talk:1347:_t_Distribution&diff=63373Talk:1347: t Distribution2014-03-26T11:51:35Z<p>173.245.52.27: the paper is data</p>
<hr />
<div>http://en.m.wikipedia.org/wiki/Student%27s_t-test<br />
<br />
<br />
[[Special:Contributions/173.245.50.73|173.245.50.73]] 05:20, 26 March 2014 (UTC)Adam<br />
<br />
<br />
I think this is a comment of the quality of education today - it is difficult to grade students on a distribution curve and even more so when you take into account the distribution curve of the teachers ability. {{unsigned ip|108.162.249.205}}<br />
<br />
I noticed the teacher's curve is symmetrical, and after further inspection it could be interpreted as an edge detection: high values show where an edge occurs. The two highest peaks would nicely align with the edges of the paper, the next highest peaks fit the edges of the table, and the rest could be approximation artefacts, as they're equidistant and rather insignificant compared to those four. I'm not statistics pro, but maybe that rings someone's bells? [[Special:Contributions/108.162.210.239|108.162.210.239]] 07:56, 26 March 2014 (UTC)<br />
<br />
:Interesting observation. It may play into an age-long legend told and re-told among the students that some teachers grade papers by tossing the whole pile in the air; those sheets that land on the teacher's desk get a pass, those falling to the floor get a fail. Sometimes the story gets modified in such a way that papers falling on the teacher's book (or other object) laying on the desk will get a higher marking than those simply hitting the desk. The latter version would explain the higher sheet-size-apart peaks. [[Special:Contributions/108.162.210.111|108.162.210.111]] 08:57, 26 March 2014 (UTC)<br />
<br />
To be more explicit, I think the sheet of paper represents some data. Cueball is not happy with the results of applying Student's t test, so ze is trying more complex tools in the hope of getting significance. -- TimMc / [[Special:Contributions/173.245.52.27|173.245.52.27]] 11:51, 26 March 2014 (UTC)</div>173.245.52.27https://www.explainxkcd.com/wiki/index.php?title=1332:_Slippery_Slope&diff=617191332: Slippery Slope2014-03-04T16:31:22Z<p>173.245.52.27: /* Explanation */</p>
<hr />
<div>{{comic<br />
| number = 1332<br />
| date = February 19, 2014<br />
| title = Slippery Slope<br />
| image = slippery_slope.png<br />
| titletext = Sure, taking a few seconds to be respectful toward someone about something they care about doesn't sound hard. But if you talk to hundreds of people every day and they all start expecting that same consideration, it could potentially add up to MINUTES wasted. And for WHAT?<br />
}}<br />
<br />
==Explanation==<br />
{{incomplete|Title text is missing; the explain is confusing and fixed to a bad compromise Randall wouldn't like.}}<br />
The "{{w|Slippery slope}}" argument hinges on the idea that if A happens, then B will follow as a minor but expected consequence. B will lead on to C, C leads onto D, and so on. Each consequence gets progressively worse until you reach an undesirable situation. A slippery slope argument intends to argue that A should not be allowed, because if it does then this chain of consequences will lead to the undesirable situation. <br />
<br />
In the comic, [[White Hat]] uses a slippery slope argument to [[Cueball]], to justify being inconsiderate to people (which is an unusual context for this argument). He argues that if he expends minor effort being considerate to one person, he will be expected to be considerate to everyone he meets, which - he wishes to argue - is an undesirable situation. Thus, he justifies being inconsiderate as avoiding the slippery slope. This idea is extended in the title text, where he continues extrapolating the train of thought to come to the conclusion that minutes of time would be "wasted".<br />
<br />
Additionally, this is an ironic comment on how being considerate is an inexpensive (and possibly high value) investment. The commentary points out it may add up to "minutes" wasted, and leads the reader to conclude "and for what" while "minutes" are an inexpensive investment and the return, friendship, is valuable.<br />
<br />
==Transcript==<br />
:[White Hat talking to Cueball.]<br />
:White Hat: Yeah, but if I'm considerate toward one person about one thing, what's next?<br />
:White Hat: Being nice to ''other'' people about ''other'' things?<br />
:White Hat: Where does it ''end?''<br />
<br />
{{comic discussion}}<br />
[[Category:Comics featuring Cueball]]<br />
[[Category:Comics featuring White Hat]]<br />
[[Category:Logic]]</div>173.245.52.27https://www.explainxkcd.com/wiki/index.php?title=68:_Five_Thirty&diff=6171668: Five Thirty2014-03-04T16:19:23Z<p>173.245.52.27: /* Explanation */</p>
<hr />
<div>{{comic<br />
| number = 68<br />
| date = February 24, 2006<br />
| title = Five Thirty<br />
| image = five_thirty.jpg<br />
| titletext = The 8th panel is my favorite<br />
}}<br />
<br />
==Explanation==<br />
{{incomplete|None of the comics are actually explained}}<br />
At 5:30 AM, one sometimes comes up with things that seem like nonsense later.<br />
<br />
None of the twelve panels in this comic seem to have any correlation with one another, each one being its own "story," and none of them really make any sense. It is unknown whether Randall really wrote this comic while awake at 5:30 in the morning, or if he wrote it while completely alert, and as a way of saying what one's mind may experience when trying to process information at an hour when the person is not used to being awake.<br />
<br />
<br />
== Comic Panels (Numbered left to right, top to bottom): ==<br />
<br />
<br />
1: One friend tells the other that "It's 80's night at the club" and asks if the other "[wants to] go".<br />
<br />
2:<br />
<br />
3:<br />
<br />
4:<br />
<br />
5: Two people are yelling "shitshitshitshitshitshitdaylightsavingsshitshitshitshitsh". The one on the left has three arms drawn, likely depicting that he is shaking his right arm up and down. The people likely forgot to adjust their clocks for the time change and were off in their schedules, as is a common problem during the shift into daylight savings time.<br />
<br />
6:<br />
<br />
7: There is a right triangle with the right angle pointing down left subtitled "FUCK THE COSINE". The farthest left angle in the triangle is labeled theta. The joke is that finding the cosine, the length of the adjacent leg divided by the length of the hypotenuse, would be difficult as the adjacent leg is poorly drawn and does not resemble a straitline to be measured.<br />
<br />
8:<br />
<br />
9:<br />
<br />
10:<br />
<br />
11: A man upside down exclaims "Bachelor Party!"<br />
<br />
12: Pictures a warning sign labeled "WARNING: STRETCHY DEATH" and containing a drawing of a spider.<br />
<br />
----<br />
<br />
<br />
The title text could actually refer to two different panels. If a person chooses to read the comic left-to-right, top-to-bottom, the eighth panel could be the one with where Cueball asks "Does being a mermaid for five minutes make you gay?" However, if a person chooses to read the comic top-to-bottom, left-to-right, the eighth panel will instead be the one with Cueball hanging upside down shouting "Bachelor party!"<br />
<br />
==Transcript==<br />
:Comics from 5:30 AM<br />
:[A succession of unrelated and completely random panels.]<br />
<br />
:Cueball: It's 80's night at the club. Wanna go?<br />
<br />
:Friend: There is no Tuesday.<br />
:Cueball: Jack the Ripper or Jack Black?<br />
<br />
:[Cueball in this panel is holding a glinting sword.]<br />
:Friend: You crashed my helicopter!<br />
:Cueball: Verily!<br />
<br />
:[A small figure is talking with a larger figure.]<br />
:Figure 1: Basically, neither of us have shins.<br />
:Figure 2: Over and out.<br />
<br />
:[Two men are shown: one with three arms, and another with just two. All arms have round appendages at their ends.]<br />
:Men: shitshitshitshitshitshitdaylightsavingsshitshitshitshitsh<br />
<br />
:[Two figures with pumpkins (carved with faces) for heads.]<br />
:Figure 1: You're out of ointment and out of time!<br />
<br />
:[A diagram of a right-angled triangle, with a theta at the smallest angle.]<br />
:FUCK THE COSINE<br />
<br />
:Friend: Does being a mermaid for five minutes make you gay?<br />
:Cueball: I hope so!<br />
<br />
:[The friend is holding a gun to Cueball's head.]<br />
:Friend: Barbershops are for pussies.<br />
<br />
:Friend: My hair is bleeding.<br />
:Cueball: √3<br />
<br />
:[Cueball seems to be walking on the ceiling.]<br />
:Cueball: Bachelor party!<br />
<br />
:[Warning sign with picture of an ant.]<br />
:WARNING: STRETCHY DEATH<br />
<br />
{{comic discussion}} <br />
[[Category:Comics featuring Cueball]]<br />
[[Category:Math]]</div>173.245.52.27https://www.explainxkcd.com/wiki/index.php?title=687:_Dimensional_Analysis&diff=61714687: Dimensional Analysis2014-03-04T15:47:26Z<p>173.245.52.27: /* Explanation */</p>
<hr />
<div>{{comic<br />
| number = 687<br />
| date = January 11, 2010<br />
| title = Dimensional Analysis<br />
| image = dimensional_analysis.png<br />
| titletext = Or the pressure at the Earth's core will rise slightly.<br />
}}<br />
<br />
==Explanation==<br />
Cueball has a [[My Hobby|hobby]] — showing correct calculations according to the {{w|dimensional analysis}} — but with ridiculous correlations of uncorrelated events and measurements. Here Cueball is teaching a class and uses this trick to ''convince'' his students that the {{w|Toyota Prius}} combined {{w|United States Environmental Protection Agency|EPA}} gas mileage is somehow connected to the constant {{W|Pi}} via the {{w|Planck energy}}, the pressure at the {{w|Inner_core|earth's core}} and the width of the {{w|English Channel}}. <br />
<br />
This comic makes fun of how scientists — often physicists — use dimensional analysis to quickly check if a given formula can possibly relate to a physical system or if there were some obvious mathematical errors in its derivation. Dimensional analysis here refers to the check if both sides of the equation arrive at the same physical unit if the units of all variables get plugged into the equation. This usually requires knowledge of the system of units and the relation between different physical units.<br />
<br />
The comic uses the following equation to make fun of it:<br />
<br />
(Planck energy) / (Pressure at the core of the earth) * (Prius combined EPA gas mileage) / (minimum width of the English Channel) = π<br />
<br />
===Dimensional analysis===<br />
The right hand side is dimensionless, it's the constant π = 3.14... which is defined by the relation of two lengths, the circumference and the diameter of a circle. The left hand side requires to plug in the dimensions of the named physical quantities:<br />
<br />
*Planck energy: given in Joules [J]<br />
*Pressure at the core of the earth: Given in Pascals [Pa]<br />
*Prius combined EPA gas mileage: miles/gallon, SI units: meters/litres [m/l]<br />
*minimum width of the English channel: meters [m]<br />
<br />
When plugged into the left hand side this amounts to:<br />
<br />
[J / Pa * (m/l) / m] = [Nm / (N/m²) * (m/m³) / m] = 1<br />
<br />
Using the following unit relations (this does not reduce units to the seven SI units, but does use some derived units):<br />
<br />
*1 Joule = 1 Newton-meter [J] = [Nm]<br />
*1 Pascal = 1 Newton per square-meter [Pa] = [N/m²]<br />
*1 cubic-metre = 1000 litres [m³] = 1000 [l]<br />
<br />
Note that for dimensional analysis constant factors are not taken into account. Here square brackets are used to denote dimensional analysis. In the above equation the unit of force (newton) as well as all the units of length (meter) cancel out each other.<br />
<br />
Another aspect of the comic is, that sometimes dimension analysis of equations that were not derived but rather "made up" can provide insight. However, in reality such an equations would have to be somehow "motivated", which is more of an art than science and requires great experience in the field the equation should relate to. The presented equation combines values that have no immediate causal relation with each other, so it does not make sense. Furthermore, since the values have absolutely no causal relation to each other, the ratios presented are simple coincidence; despite Cueball's claim, building a better Prius would not cause any changes to the English Channel. <br />
<br />
In addition, if a better Prius were built, with a higher gas mileage, the equation would only be accurate if one of the other quantities changed. A higher gas mileage could be balanced if the English Channel became wider thus explaining why Cueball states that England will drift to sea away from France. <br />
<br />
The title text also refers to this, as a higher pressure at Earth's core could also balance the equation, keeping the result constant equal to Pi. The Planck energy is an absolute, however, so it is not mentioned as a way to balance the next version of Prius.<br />
<br />
===Some numbers for this calculation===<br />
The {{w|Planck energy}} is the only nearly exact value we do have. Compared to other Planck values it is very large (macroscopic).<br />
E_planck = 1.956 x 10<sup>9</sup> J = 1.956 x 10<sup>9</sup> Nm<br />
<br />
Pressure at the {{w|Inner_core#Temperature_and_pressure|core}} of the earth ranges from 330 to 360 gigapascals.<br />
Using a simple value like this:<br />
P_core = 350 GPa = 3.5 x 10<sup>11</sup> N/m²<br />
<br />
Prius combined {{w|Toyota_Prius#Fuel_economy_and_emissions|EPA gas mileage}}:<br />
For the third generation (from 2010) the City mileage is 51 mpg and the Highway mileage is 48 mpg. But it is the [http://www.fueleconomy.gov/feg/Find.do?action=sbs&id=26425 combined EPA gas mileage] which is used in the equation and that is 50 mpg.<br />
50 mpg => 13.2 miles per litre => 21,000,000 meter per m³<br />
<br />
Minimum width of the {{w|English Channel}} is about<br />
33.1 km or 33,100 meters.<br />
<br />
Calculating from these values you will get π=3.54... that is pretty close to π=3.14... while using a Planck value. According to Cueball this will be within the experimental error (the combined error for all four numbers - none are exact numbers). For instance if you tried the ePrius you would probably get closer to that target — as the mileage in real life usually is somewhat lower than the value given — and that would reduce the result.<br />
<br />
==Transcript==<br />
:My Hobby:<br />
:Abusing dimensional analysis<br />
<br />
:[On a blackboard.]<br />
:(Planck energy/Pressure at the Earth's core) x (Prius combined EPA gas mileage/Minimum width of the English Channel) = π<br />
<br />
:[Cueball indicates this equation with a pointer in front of a class.]<br />
:Cueball: It's correct to within experimental error, and the units check out. It must be a fundamental law.<br />
:Student: But what if they build a better Prius?<br />
:Cueball: ''Then England will drift out to sea.''<br />
<br />
==Trivia==<br />
*Interestingly, this sort of dimensional analysis is formalized by the so called {{w|Buckingham π theorem}}, where each dimensionless grouping is called a "Pi". Thus formally each grouping can be denoted as equal to "Pi", although this is a rather obscure pun in the context of the comic.<br />
*The {{w|fine-structure constant}} α =~ 1/137 is a common known analogue in {{w|physics}}.<br />
*This is another comic in the infrequent [[My Hobby]] series.<br />
<br />
{{comic discussion}}<br />
[[Category:My Hobby]]<br />
[[Category:Comics featuring Cueball]]<br />
[[Category:Comics featuring Ponytail]]</div>173.245.52.27