explain xkcd - User contributions [en]

2882: Net Rotations

2024-10-23T13:23:51Z

172.70.91.72: /* Explanation */ Here's the corrected version, then.

{{comic
| number = 2882
| date = January 17, 2024
| title = Net Rotations
| image = net_rotations_2x.png
| imagesize = 318x477px
| noexpand = true
| titletext = For decades I've been working off the accumulated rotation from one long afternoon on a merry-go-round when I was eight.
}}

==Explanation==
This is another one of [[Randall|Randall's]] [[:Category: Tips|Tips]], this time a Spacetime health tip.

This comic may refer to a thing that some people with {{w|OCD}} do, which is to spin around to get rid of "net rotations," hence the title of this comic. [[Cueball]] (perhaps representing [[Randall]]?) takes this one step beyond the typical person with OCD - he calculates the net rotations each day and spins around at the end of the day to cancel this out. In this case, he would be spinning left 17 rotations to return to zero.

The offered reason for the necessity to do this is a physics joke: the reference to spacetime and to one's "worldline" has to do with relativity and the {{w|Einstein-Cartan theory}}, which is an extension of Einstein's general relativity. The theory suggests a coupling between the intrinsic spin of elementary particles (fermions) and the torsion of spacetime, and this comic appears to humorously extrapolate this idea to even supermolecular structures like a human, telling readers to "cancel out your accumulated turns at the end of each day to avoid worldline torsion", where in reality, it is highly unlikely the spin on such a large scale would cause any torsion in anyone's worldline, or their path traced by a particle or observer in spacetime.

A mobile device with position and orientation sensing might be able to keep track of one's net rotations, eliminating the need for calculations. One would need only to do one's spinning while monitoring the device to see when it returned to zero.

The caption suggests that this is healthy and necessary/highly recommended to do this. However, most people don’t, and most people are still OK.{{Citation needed}} In fact, xkcd's own characters are perfectly OK with [[162: Angular Momentum|accumulating net rotations]] and [[2679: Quantified Self|similar topological excesses]].

Possibly a reference to the 1966 novel, [//archive.org/details/revolvingboy0000frie The Revolving Boy] by {{w|Gertrude Friedberg}} whose protagonist suffered from being out of correct positioning depending on the number of turns he was forced to make in his everyday life.

The relationship between spinning and spacetime was formerly discussed in [[162: Angular Momentum]].

The title text mentions that Cueball was on a {{w|merry-go-round}} when he was eight and he accumulated so many rotations that he's still trying to counter these rotations to this day.

==Transcript==
:[Cueball is rotating around himself with only one foot on the ground, the other leg raised and bend above the ground and with his arms crossed in front of his chest. There are five circular curves around Cueball from head to legs to indicate this rotary motion. He rotates in front of a whiteboard. On the left of the board there are two vertical helix-like curves going from near the top to the bottom. They are crossing over each other at five points, the first four crossings close to the top, and then one near the bottom. Next to this there are ten rows of illegible scribbles, then a line, then another row of scribbles then a line and at the bottom a row of scribbles which is circled in. There is a large thought bubble above Cueball to indicate that he is thinking to himself while rotating in front of his calculations on the whiteboard.]
:Cueball (thinking): ...and three lefts for going down the stairwell at work, two rights from cloverleaf interchanges, minus one for the Earth's rotation...
:Cueball (thinking): Okay, that's a net of 17 right.

:[Caption below the panel:]
:Spacetime health tip: Remember to cancel out your accumulated turns at the end of each day to avoid worldline torsion.

{{comic discussion}}

[[Category:Comics featuring Cueball]]
[[Category:Astronomy]]
[[Category:Physics]]
[[Category:Tips]]

Talk:2993: Ingredients

2024-10-04T10:34:03Z

172.70.91.72:

Added a quick draft of an explanation. Is it good? [[Special:Contributions/172.68.147.164|172.68.147.164]] 07:44, 3 October 2024 (UTC)
: sign your damn comment [[User:CalibansCreations|'''Caliban''']] ([[User talk:CalibansCreations|talk]]) 07:16, 3 October 2024 (UTC)
:: Be more f'ing polite![[Special:Contributions/172.70.85.138|172.70.85.138]] 08:59, 3 October 2024 (UTC)

How hard would this really be? I feel like we could do this by messing with different orbits and just crashing the moons into each other.[[User:Anonymouscript|Anonymouscript]] ([[User talk:Anonymouscript|talk]]) 20:42, 3 October 2024 (UTC)
:Hard if you don't want to change everything into molten lava temporarily. [[Special:Contributions/172.71.166.61|172.71.166.61]] 08:21, 4 October 2024 (UTC)
::I think 'temporarily' doesn't sound too bad... ;) [[Special:Contributions/172.70.91.72|172.70.91.72]] 10:34, 4 October 2024 (UTC)

Isn't this the plot of the first Ratchet & Clank game? {{unsigned ip|172.68.22.98|22:26, 3 October 2024}}

;Voice actor speculation
Since we're rapidly approaching number 3000, let's designate voice actors to the xkcd cast.

Beret Guy could be voiced by Michael Kovach, doing the same voice as he does for N from Murder Drones.

Black Hat could be voiced by JamsDX, with the same voice he did for X in his cover of Obituary.

And so on. [[User:CalibansCreations|'''Caliban''']] ([[User talk:CalibansCreations|talk]]) 07:46, 3 October 2024 (UTC)
:It would help if I knew who either of those were, or even the things that they are described as doing. And I suspect my own prospective choices would be similarly unknown to you. ;) [[Special:Contributions/172.70.85.62|172.70.85.62]] 08:35, 3 October 2024 (UTC)
::here's [https://youtu.be/IeUfDDz7vSg?feature=shared the n voice clips] and [https://youtu.be/YmzxwWNuYnk?feature=shared the obituary cover] i was referring to, hope this helps! [[User:CalibansCreations|'''Caliban''']] ([[User talk:CalibansCreations|talk]]) 13:03, 3 October 2024 (UTC)
::You can do whatever you like but it is not a part of explain xkcd og xkcd... --[[User:Kynde|Kynde]] ([[User talk:Kynde|talk]]) 12:17, 3 October 2024 (UTC)

Elon Musk

2024-09-30T10:13:33Z

172.70.91.72: Undo revision 351656 by 172.70.91.72 (talk) If it's relevent (love or hate him), explain it here. Bad (sole) reason to start a Talk page, though.

{{Infobox character
| image = Elon Musk.png
| imagesize = 200px
| caption = '
| first_appearance = [[1288: Substitutions]]
}}

<noinclude>:''For a list of comics, see [[:Category:Comics featuring Elon Musk|Comics featuring Elon Musk]].''</noinclude>

'''{{w}}''' is a business magnate and investor. He is the founder, chairman, CEO, and CTO of {{w|SpaceX}}, CEO and product architect {{w|Tesla, Inc.}}, owner, chairman, and CTO of {{w|X Corp.}}, CTO of {{w|Twitter|X}}, founder of {{w|The Boring Company}}, co-founder of {{w|Neuralink}} and {{w|OpenAI}}, and president of the Musk Foundation. On xkcd comics, he has only been [https://www.explainxkcd.com/wiki/images/7/73/1608_0945x1074y_Elon_Musks_cave_in_lair.png depicted once] in [[1608: Hoverboard]], where he has a [[1608: Hoverboard#Secret passages and hidden places|hidden lair]] under the Volcano in the left part of the game. In the ''[[what if? (blog)|what if?]]'' article ''{{what if|124|Lunar Swimming}}'', he is mentioned in the article and drawn swimming on the Moon in the final paragraphs, and in {{what if|143|Europa Water Siphon}} he is mentioned in the title text of the second to last image. His name was one of the [[1506: xkcloud/Transcript#User names|user names]] used in [[1506: xkcloud]].

{{navbox-characters}}
[[Category:Characters]]
[[Category:Real people]]

Elon Musk

2024-09-30T02:25:52Z

172.70.91.72: Please create talk page

1342: Ancient Stars

2024-09-01T09:49:21Z

172.70.91.72: /* Explanation */ Not a biblical name (that being an exception to the rule that I blame on the unformed literacy of early monk-scribes, and I don't even know why we should honour that principle), so much better to use the unvarnished version.

{{comic
| number = 1342
| date = March 14, 2014
| title = Ancient Stars
| image = ancient_stars.png
| titletext = 'The light from those millions of stars you see is probably many thousands of years old' is a rare example of laypeople substantially OVERestimating astronomical numbers.
}}

==Explanation==
[[Cueball]] makes the common observation that many of the visible stars in the sky are so distant that it takes thousands of years for light from that star to reach Earth. However, the brightest star {{W|Sirius}} is one of the nearest at a mere 8.6 {{W|Light-year|light-years}} distance. In other words, the light that was arriving from Sirius in March 2014, when the comic was posted, was emitted some time around August 2005. The previous US president, {{W|George W. Bush}}, was in office from 2001 to 2009 and [[Megan]] notes that this isn't a terribly impressive observation. At certain times (mostly when the previous US president served only a single term, but also {{w|Twenty-second Amendment to the United States Constitution|currently}} for a short time after the inauguration of any incoming president), looking to events of 8.6 years ago would stretch ''beyond'' just the prior administration, but even two ({{w|Ronald Reagan|rarely}} being {{w|Richard Nixon|three}}, or {{w|Grover Cleveland#First presidency (1885–1889)|possibly}} even {{w|Ulysses S. Grant|more}}) predecessors ago would not be considered impressive in the circumstances.

The title text references the fact that most people have a hard time imagining the large scale of astronomical numbers. For example, the distance between astronomical bodies or the size of the Sun are hard to imagine; they typically underestimate them by many orders of magnitude and think they are much smaller than they actually are. See {{tvtropes|SciFiWritersHaveNoSenseOfScale|Sci-Fi Writers Have No Sense of Scale}}

In this case, however, people instead overestimate both the number of visible stars and their distance by quite a bit. This could be a result of underestimating the speed of light, which is rather fast. Even though stars are incredibly far away (Sirius's 8.6ly translates to over 80 trillion kilometers), light is so fast that it can crosses those distances as fast as anything can (a relative blink in the eye, for the ''nearest'' of these vast distances). This underestimate of light results in an overestimate of the time it takes for light to reach us.

It's frequently cited that about 5,000 to 10,000 stars are visible in the sky by the naked eye. The {{W|Bright Star Catalogue}} is a star catalogue that lists all stars of {{W|apparent magnitude}} 6.5 or brighter, which is roughly every star visible to the naked eye from Earth. The catalog contains 9,110 objects, of which 9,096 are stars, ten are {{w|Nova|novae}} or {{w|supernovae}}, and four objects outside of our Milky Way (two {{w|globular cluster}}s and two {{w|open cluster}}s). To see most of these you need good eyes and a very dark night, and at any point you will only be able to see fewer than half of these as the rest are blocked by the Earth.

This list shows the {{W|Visible stars|91 brightest stars}}. Of these 59 are more than 100 light years away and only 6 are more than 1,000 light years away. The farthest on this list, {{W|Eta Canis Majoris|Aludra}}, is "only" 3,200 light years away. Our entire {{w|Milky Way}} contains up to 400 billion (400x10⁹) stars and has a diameter of 100,000 light years.

There are visible objects much farther away, like the {{w|Andromeda Galaxy}} which is 2.5 million light years away and made up of billions of stars. And a gamma ray burst {{w|GRB 080319B}} would have been briefly visible to the naked eye, despite being 7.5 billion light years distant.

See also [[1212: Interstellar Memes]], [[1644: Stargazing]] and [[1440: Geese]].

==Transcript==
:All of the panels of this comic are white-on-black.

:[Megan and Cueball stand facing each other, looking up at the sky.]
:Cueball: Just think - the light from that star was emitted thousands of years ago. It could be long gone.

:[Cueball looks at Megan, who is still looking up.]
:Megan: That's Sirius. It's eight light-years away.

:[Cueball looks up again.]
:Cueball: Oh.

:[Both look at one another.]
:Cueball: Just think - the light from that star was emitted in the previous presidential administration.
:Megan: Hmm, doesn't pack quite the punch.

==Trivia==
*The star {{W|List of stars in Cassiopeia|V762 Cas}} in the {{W|Cassiopeia (constellation)|Cassiopeia constellation}} is listed as being 14818 light years away and still having an {{W|apparent magnitude}} of 5.87 - thus being within the visible 6.5 limit. If Cueball had been able to point this star out, he would have been correct. But it is only visible under perfect conditions.

{{comic discussion}}
[[Category:Comics with inverted brightness]]
[[Category:Comics featuring Cueball]]
[[Category:Comics featuring Megan]]
[[Category:Astronomy]]

2978: Stranded

2024-08-29T12:09:50Z

172.70.91.72: /* Transcript */ More than just "large round" edit.

{{comic
| number = 2978
| date = August 28, 2024
| title = Stranded
| image = stranded_2x.png
| imagesize = 219x323px
| noexpand = true
| titletext = At least they're not alone down there.
}}

==Explanation==
{{incomplete|Created by a TWO ASTRONAUTS THAT ARE ABSOLUTELY NOT STRANDED NOSIREEBOB - Please change this comment when editing this page. Do NOT delete this tag too soon.}}

This comic is making fun of the {{w|Boeing Starliner}}, which launched for its Crewed Flight Test on June 5th, 2024. The mission to the {{w|International Space Station}} was originally scheduled for only eight days, but as of the comic’s release (Aug 28, 2024) the astronauts, Butch Wilmore and Suni Williams, are still "stranded" on the ISS.

The comic points out that being stranded is a matter of perspective and circumstances; people on Earth could equally be considered "stranded", unable to get off the planet. Many science fiction stories deal with some sort of rush to evacuate the Earth, though there's usually a reason why they would wish to leave, a reason that's notably absent in the comic. Moreover, the proposed solution of one rocket would not be able to bring all 8 billion people on Earth to space.{{cn}}

The comic is also making fun of the fact that during press conferences, NASA has stressed that the Starliner astronauts are not actually stranded, because there are procedures for emergency returns to Earth, yet they're not expected to return until February 2025, on a {{w|SpaceX Crew_Dragon}}.

The title text references commentators saying that at least the Starliner crew aren't alone up there, as there are currently nine people aboard the ISS, but flips it around to be about the (8 billion) people on Earth. Another funny take on the title text would be that in the turbulent times the fact that one is "stranded" like this might even be a benefit.

==Transcript==
:[Two astronauts, Megan and Cueball, are shown floating in the cabin of a space station, Megan near the top and Cueball near the bottom. Various miscelaneous devices and features are visible, all across the inner walls of the space station, as well as a large round window through which they can see some of Earths surface. Three white shapes are visible that could represent continents between seas or oceans, or else represent weather systems.]
:Megan: Until they get another rocket ready to launch, 8 billion people are stranded down there.

{{comic discussion}}

[[Category:Comics featuring Megan]]
[[Category:Comics featuring Cueball]]
[[Category:Space]]