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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: 0.2s | source
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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

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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?

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btilly ◴[31 Mar 25 15:33 UTC] No.43536223[source]▶
In all known physical processes, the baryon number is conserved. Particles with a positive baryon number are the heavy particles in matter. Think protons, neutrons, and so on. Particles with a negative number are antimatter. Think antiprotons, and antineutrons. And particles with a 0 baryon number are not made of quarks. Think leptons like electrons and neutrinos, or bosons like photons and the Higgs boson.

This means that all known ways to create or destroy matter, also creates or destroys an equal amount of antimatter.

It turns out that most attempts to extend the Standard Model allow violations of baryon conservation. This could explain the dominance of matter in our universe. However none of those attempts have been able to make any predictions that matched experiment. And so it remains true that all known physical processes perfectly conserve the baryon number.

(It is also possible that baryon number really is conserved, and dark matter is actually dark antimatter. But we lack a theory of what dark matter could be that predicts this.)

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1. adrian_b ◴[31 Mar 25 16:07 UTC] No.43536600[source]▶
Even if in the strong, weak and electromagnetic interactions the baryon number is conserved, there is the interesting fact that for the 8 particle set composed of the 3 kinds of u quarks, 3 kinds of d quarks, 1 electron and 1 neutrino, the sum of all kinds of quantities that are expected to be conserved, like electric charge, color charges and spin sum to zero. This set of 8 particles is also equivalent with the set of the components of one proton, one neutron, one electron and one neutrino.

This property of this set of 8 particles is analogous to the similar property of the set of 2 particles composed of a particle and its anti-particle, and to the similar property of the sets of 4 particles that can be involved in a weak interaction (the intermediate weak bosons convert one 4-particle interaction into a couple of 3-particle interactions, but when looking at the overall inputs and outputs, all the weak interactions are 4-particle interactions), which ensure the conservation of various quantities over such interactions.

This means that it is possible to conceive an additional kind of interaction, which unlike electromagnetic interactions between 2 particles and weak interactions between 4 particles, involves 8 particles, so it has a much smaller probability of occurring, i.e. it is a much weaker interaction than the weak interaction, and through which, when provided with enough energy, quarks + electrons + neutrinos could be generated simultaneously without generating anti-matter.

While there is no evidence yet for such an interaction, it is conceivable that at least during the circumstances of the Big Bang, such an interaction could have existed, so all the quarks and leptons could have been generated from some unknown bosons, just with enough initial energy and with conservation of all quantities for which there are solid reasons to believe that they must always be conserved, like energy, linear momentum, angular momentum, electric charge and color charges. (Unlike for the baryon number, for which there is no other reason to believe that it must be conserved, except that the strong, weak and electromagnetic interactions happen to have this behavior.)