Talk:2967: Matter

This one is a head-scratcher. Do skateboarders call "anti-" things goofy? What's the deal with that Dirac statistic? 162.158.154.31 23:47, 2 August 2024 (UTC)

It's like being a 'southpaw' boxer (or at least being able to stand the opposite way, maybe in order to flip/spin the board the opposite way from what you would end up kicking it normally).

The Dirac thing is... well, quantum physics has various uses/restrictions upon spin (and colour, etc) that isn't really physical spin (or colour) as we know it, but sort of means a kind of particle-based rotational momentum, which has to be conserved/transfered/agree in various quantum interactions (and is a quantised state, meaning that only certain spin-values can exist in a given situation).

Both the skateboarding and the elementary physics issues are (in their own way) rather technical matters, and I know a lot more about one than the other (but think I understand the other a lot more, from just reading up on it, than I know I actually understand the original one based on what I actually was taught). 172.70.162.186 00:03, 3 August 2024 (UTC)

"Do skateboarders call "anti-" things goofy?" FWIW, I first heard 'goofy' in the 1960s skateboard fad, using your left foot where the right foot normally goes. It appears this was 2 or 3 years before Mr Hawk was born, so it isn't his invention. I would wonder if surfers (Hawaii and California) got goofy even earlier. PRR (talk)

Looks like a fair summary: Goofy Foot --PRR (talk) 02:21, 3 August 2024 (UTC)

I first heard the term "goofy foot" back in Skate or Die on the NES. 162.158.212.133 07:59, 3 August 2024 (UTC)

I'm way over the hill, and that linked 20 minute video on spin was the first explanation of that quantum number which seemed fully satisfactory and didn't leave me feeling like I was missing something crucial. https://www.youtube.com/watch?v=pYeRS5a3HbE&t=18m30s "The spin number characterizes how fast the state of a particle changes when we rotate it in space." WHERE HAS THAT EXPLANATION BEEN ALL MY LIFE?!?! 172.68.22.90 04:56, 3 August 2024 (UTC)

Spin is a terrible name, it should be "twist factor" for example. It's a derivative unit error, like calling acceleration in terms of speed. 162.158.90.198 07:58, 3 August 2024 (UTC)

Problem loading previous comic, I get MediaWiki error. SDSpivey (talk) 17:15, 3 August 2024 (UTC)

Can't replicate that, and doesn't sound like the kind of errors I might get (504s, "sorry too busy"-style message, etc). Is it still happening for you? 172.70.85.18 19:23, 3 August 2024 (UTC)

This part doesn't make any sense to me; was this section AI generated? "That is why it is very difficult to compress matter based on fermions and even to get goofy matter (which are not identical particles), as they should be brought in contact with in the comic, near enough or mixed enough with the normal matter." ProphetZarquon (talk) 21:15, 3 August 2024 (UTC)

Reverted as an incorrect and confusing attempt to extend the panel joke into the title text explanation. That never goes well. 172.71.150.237 21:47, 3 August 2024 (UTC)

So in skateboard, does goofy just mean "left foot" or does it mean "non-dominant foot". Like, would a left handed skater be skating goofy "normally", or is goofy for them, using right foot?

Left, because it's described in the frame of reference of observers. 172.70.214.34 07:35, 4 August 2024 (UTC)

Have made a new Category:Skateboard. There have for a long time been one for Electric Skateboard but I found 10 with regular skateboards being referenced. --Kynde (talk) 09:08, 4 August 2024 (UTC)

The extra spacing in the Feynman diagram on the blackboard explains why most antimatter was annihilated. 172.69.135.89 10:00, 4 August 2024 (UTC)

Given an initial universe with equal parts matter and antimatter plus a slight asymmetry (50% + e), the mutual annihilation of matter and antimatter would leave behind a residual amount of matter proportional to the asymmetry e. In the extremely dense early universe, this annihilation would be nearly complete, ensuring that almost all antimatter and a corresponding amount of matter would be annihilated into energy, leaving an excess of matter. Thus, the observed baryon asymmetry today can be explained by this initial slight asymmetry, as even a minuscule e would result in a predominantly (anti)matter-filled universe post-annihilation. 172.70.210.52 10:33, 4 August 2024 (UTC)

It does mean that mass-energy conservation (or ways to feed that energy into other things, e.g. the expansion of space itself?) gives us a different initial distribution to the kind of initial universe where the imbalance was never just a residual (anti-particals just naturally being rarer to find/be created), and still begs the question of where such an imbalance came from (however small) from a spontaneously created universal 'seed' that one would imagine ought to be 'property neutral' in combining all essentially symmetric measures. But I added a little something about this to my own edit. (My edit being an attempt to stop huge run-on sentences with comma asides (and other dubious usages of comma), in a key section. So much so that I gave up trying to work out what some of it was intended to mean and just gave my own version. Still with plenty of commas, but not relying quite so heavily upon them alone.) 172.69.195.231 11:53, 4 August 2024 (UTC)

No, it does not. 172.70.207.39 14:22, 4 August 2024 (UTC)

What is wrong there? (I can see some messy understanding, but there's also some practical correctness.) What (especially with the changes to remove, loads, of, long, comma-ey, back, and, forth, sentences; it definitely does need rewriting, as it now is again!) required the whole lot reverting? 172.70.86.38 18:12, 4 August 2024 (UTC)

I reverted https://www.explainxkcd.com/wiki/index.php?title=2967:_Matter&diff=348077&oldid=348076 because reality. 172.69.22.196 13:06, 4 August 2024 (UTC)