explain xkcd - User contributions [en]

Talk:3032: Skew-T Log-P

2025-01-02T05:47:15Z

172.70.206.65:

...did the ip address user really just have chatgpt write an explanation of this page without a proper understanding of what is happening in this page? the only reasonable content in this explanation page right now was contributed by other users and is a couple lines at the beginning. also they didn't even try to hide that the entire text was AI-generated - [[User:Vaedez|Vaedez]] ([[User talk:Vaedez|talk]]) 05:09, 2 January 2025 (UTC)

: Better than hiding it. I'm guessing they just wanted to help but didn't know what the graph in question was. But I'm gonna go out on a limb and assume this mostly vapid explanation is as good as no explanation, and remove it for now. [[Special:Contributions/108.162.216.132|108.162.216.132]] 05:42, 2 January 2025 (UTC)

:Bringing a whole new meaning to the default "Created by a bot" unfinished message --[[Special:Contributions/172.70.214.157|172.70.214.157]] 05:43, 2 January 2025 (UTC)

skewtie --[[Special:Contributions/172.70.206.65|172.70.206.65]] 05:47, 2 January 2025 (UTC)

2688: Bubble Universes

2024-08-19T14:36:04Z

172.70.206.65: /* Explanation */ Oops, messed up the formatting 🥴

{{comic
| number = 2688
| date = October 21, 2022
| title = Bubble Universes
| image = bubble_universes_2x.png
| imagesize = 740x188px
| noexpand = true
| titletext = The theory finally unifies cosmic inflation and regular inflation.
}}

==Explanation==

A {{w|Eternal_inflation#Overview|bubble universe}} is a concept in the {{w|Inflation (cosmology)|inflation theory of cosmology}} in which our observable universe is just one of many "bubbles" of matter and radiation that formed after the {{w|Big Bang}}.

The comic seems to be recursive, where one Cueball's bubble universe contains another Cueball doing the same thing, blowing bubbles, seeming to contain the whole scene within one of the bubbles in the original scene.

The title text claims this theory "Finally unifies cosmic inflation and regular inflation." Cosmic inflation refers to the expansionary phase of the universe shortly after the Big Bang. Meanwhile, Regular inflation refers to blowing bubbles, as this leads to them being inflated{{citation needed}}. This comic "unified" these theories with the simple proposition that the universe was a bubble and inflated like regular bubbles do. Unification of theories is a popular goal among scientists, since it makes it possible to provide a single explanation for multiple phenomena.

==Transcript==
:[Cueball blowing expanding bubbles. In the largest one is a whole new universe with another Cueball blowing similar bubbles. The bubbles are progressively darker: the first ones are regular transparent/white bubbles, and as they grow, they turn gray then dark, to match the black night sky, with stars, galaxies, planets and other astronomical bodies]

{{comic discussion}}
[[Category:Cosmology]]
[[Category:Comics featuring Cueball]]
[[Category:Multiple Cueballs]]
[[Category:Puns]]
[[Category:Recursion]]

2967: Matter

2024-08-05T22:48:05Z

172.70.206.65: /* Explanation */ video link include entire differentiating clause

{{comic
| number = 2967
| date = August 2, 2024
| title = Matter
| image = matter_2x.png
| imagesize = 234x341px
| noexpand = true
| titletext = He was the first person to land a 900, which is especially impressive because pulling off a half-integer spin requires obeying Fermi-Dirac statistics.
}}

==Explanation==
{{incomplete|Created by a GOOFY FRONTSIDE WIKI GRIND TO SECRET PHYSICS DEMO TAPE - Please change this comment when editing this page. Do NOT delete this tag too soon.}}

In {{w|skateboarding}}, the term "goofy" means to push with the left foot, using the {{w|Footedness#Goofy_stance|opposite stance}} to the supposedly standard stance of pushing with one's right foot. The comic uses the goofy stance as an analogy for {{w|antimatter}} in particle physics, which exhibits the opposite charge to ordinary matter and will annihilate both upon collision with its counterpart, releasing energy proportional to their combined mass. In this comic, famed professional skateboarder {{w|Tony Hawk}} has obtained a professorship in physics and is teaching the theory with this non-standard terminology borrowed from his other field of expertise. 'Professor' Hawk already has an early xkcd comic named after him: [[296: Tony Hawk]].

Hawk's presence here could in part be inspired by professor {{w|Stephen Hawking}}, a famous astrophysicist at the University of Cambridge who died in 2018. As Tony Hawk does not have a degree in physics,{{Citation needed}} teaching inaccurate lessons could be a likely pitfall of his gaining a professorship in real life.

Unlike other distributions of handedness in the natural world (chemical {{w|chirality}}, or the {{w|skewness}} of {{w|Multimodal distribution|bimodal statistics}} describing asymmetries in nature called {{w|homochirality}}), 'goofy-footed' skateboarders are about as common as those using standard footing. The analogy indirectly raises the issue of {{w|baryon asymmetry}}, the observation that ordinary matter is very much more common than antimatter because there is so little evidence of annihilation throughout the universe. Baryon asymmetry is often thought to have resulted from fluctuations during {{w|Inflation (cosmology)|cosmological inflation}} between 10<sup>−33</sup> and 10<sup>−32</sup> seconds [https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.121.251301 after the Big Bang], although there are several other candidate explanations of varying falsifiability.

The title text describes Hawk as the first person to "land a 900," meaning the [https://www.youtube.com/watch?v=4YYTNkAdDD8&t=1m30s successful completion] of {{w|900 (skateboarding)|a skateboarding trick}} that involves two and a half rotations, i.e. nine hundred degrees (2.5 × 360° = 900°). In physics, {{w|Spin (physics)|spin}} is a {{w|quantum number}} describing subatomic particles (see [[1862: Particle Properties]]), named in reference to the vaguely analogous ''but crucially distinct'' concept of {{w|angular momentum}} in classical physics. Obeying {{w|Fermi–Dirac statistics}} requires that the particles involved are {{w|fermion}}s, which include all of the electrons, protons and neutrons that comprise the entirety of everyone's body and electrochemical state. Fermions all have {{w|half-integer}} (i.e., ...–1½, –½, ½, 1½...) {{w|spin quantum number}}s which do indeed include 2½, but only [https://physics.aps.org/articles/v7/s137 extremely rare particles] have a spin of 5/2. However, it's very important to remember that [https://www.youtube.com/watch?v=pYeRS5a3HbE&ab_channel=ScienceClicEnglish quantum mechanical spin is ''not'' rotation, but instead how quickly the corresponding particle changes state when rotated.]

While everyone (and almost everything we ordinarily interact with except light and cosmic rays) is comprised entirely of fermions, {{w|Boson#Composite bosons|any composite particle made of an even number of fermions, including entire atoms and their nuclei, are not fermions}} but {{w|boson}}s, which do ''not'' obey Fermi–Dirac statistics. Luckily, landing a 900 does not actually require obedience to Fermi–Dirac statistics because a skateboarder comprised entirely of bosonic atoms would still have fermionic electrons in the orbitals of those atoms and thus would still obey the far more macroscopically fundamental and consequential {{w|Pauli exclusion principle}} (as described in [https://www.nobelprize.org/uploads/2018/06/pauli-lecture.pdf this 1946 lecture]). That principle gives mostly empty atoms the property of substance, allowing you to hold things, walk, make sound waves with your voice and employ any mechanical property of matter. This gives a sufficiently skilled skateboarder the ability to land a 900, as well as everything else they normally do (both on and off the skateboard).

==Transcript==
:[Tony Hawk (drawn with short hair) is gesturing at a narrow whiteboard on which illegible things are marked, what may be a Feynman diagram with one of the particle/antiparticle pair going into a circle (possibly representing a black hole, and thus depicting the popularized (incorrect) analogy for {{w|Hawking radiation}}), and at the bottom, a 2x3 table of illegible values.]
:Tony Hawk: In the standard model, regular matter will annihilate if it comes in contact with oppositely-charged ''goofy'' matter.

:[Caption below the panel:]
:Tony Hawk becomes a physics professor

{{comic discussion}}

[[Category:Comics featuring real people]]
[[Category:Skateboard]]
[[Category:Physics]]
[[Category:Statistics]]