←back to thread

James Webb Space Telescope reveals that most galaxies rotate clockwise

(www.smithsonianmag.com)
352 points instagraham | 1 comments | 31 Mar 25 10:31 UTC | HN request time: 0s | source
Show context
over_bridge ◴[31 Mar 25 11:22 UTC] No.43533669[source]▶
Seems like we've got a few of these imbalances now where you'd expect 50:50 but instead it's skewed to one side where nature had a different idea

Matter-antimatter ratio

Left vs right handed molecules

Now galaxy spin directions

Maybe there are others I missed too

replies(9): >>43533690 #>>43533698 #>>43533727 #>>43533731 #>>43533744 #>>43534741 #>>43534857 #>>43534912 #>>43535232 #
albertzeyer ◴[31 Mar 25 11:30 UTC] No.43533727[source]▶
For the matter-antimatter ratio, you would not expect 50:50, or would you? Because 50:50 would be a highly unstable system? In any case, you would expect that unstable states would be highly unlikely, and it would converge into a stable state.

I'm not sure about the other examples. But maybe it's a similar reason that it is not a 50:50 ratio?

replies(5): >>43533760 #>>43534020 #>>43534051 #>>43536223 #>>43536920 #
hhjinks ◴[31 Mar 25 11:34 UTC] No.43533760[source]▶
A 50/50 matter/anti-matter system could still house stable local pockets of mostly matter or anti-matter. The problem is, from what I understand, that the universe seems to have sprung into existence with way more matter than anti-matter, and we don't know why.
replies(1): >>43534788 #
nabakin ◴[31 Mar 25 13:25 UTC] No.43534788[source]▶
Could it be that the observable universe is one of these stable local pockets and the antimatter to balance it out is simply not observable to us?
replies(2): >>43535039 #>>43539057 #
1. ben_w ◴[31 Mar 25 19:48 UTC] No.43539057[source]▶
Mathematically possible.

If you flip 2n fair coins, you expect n+δ heads and n-δ tails, where δ is (IIRC) sqrt(n/2). Going much away from that becomes infintessimally unlikely.

Probability is a subject famously easy to get wrong, so be careful with what I'm about to suggest: I *think* you could argue that in the moment prior to the inflation epoch spreading everything out just enough that pair production stops*, any given particle in our horizon is a coin toss of matter or antimatter.

Number of observed atoms in the universe is about 6e79 (http://www.wolframalpha.com/input/?i=how%20many%20atoms%20in...), so 6e79 = sqrt(n/2) -> n = 7.2e159 due to protons, and the same again for electrons; as we don't see significant signs of antimatter, any around must have annihilated a long time ago, so in this scenario we should expect to see ~7e159 (red-shifted) photons from the supermajority of particles which have annihilated.

It's outside my field to know how that compares to cosmologist's observations.

* won't that be at different times for protons/neutrons and electrons?

I can't get good answers on the expectations for either "why are protons and electrons counts the same" or "what is the observable consequence if they're not?"