Why do matter and antimatter annihilate? (bigthink.com)

submitted 5 months ago by Bebo@literature.cafe to c/science@lemmy.world

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From forming bound states to normal scattering, many possibilities abound for matter-antimatter interactions. So why do they annihilate? There’s a quantum reason we simply can’t avoid.

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[-] neidu2@feddit.nl 14 points 5 months ago

I'm a smoothbrain, so I like to think about it as them simply canceling each other out. What I'm more curious about though, is why there's so much matter compared to antimatter.

[-] slurp@programming.dev 4 points 5 months ago

That's what we genuinely don't know. Based on the standard model, it should be in equal parts.

[-] metallic_z3r0@infosec.pub 2 points 5 months ago

Part of me is still half-convinced that there are whole galaxy clusters of antimatter that are simply too far away from other clusters to produce any noticeable gamma rays, and the reason they didn't interact near the beginning of the universe is the same reason the whole thing didn't collapse into a super massive black hole: we don't know yet, but probably along the same lines as dark energy. A lot of it did probably interact though and that's where a lot of the CMB comes from.

I'm definitely a lay person though, I'm sure an actual physicist can tell me that's definitely not the case, I just don't know why not yet.

[-] slurp@programming.dev 4 points 5 months ago

My personal idea/hope is that there is some other dimension of spacetime over which the big bang had directionality, emitting matter and antimatter across different poles, and that's why. That'd also mean there's an anti-universe, which is why I like the idea.

In terms of the galaxies, I believe there's enough of an observable difference that I think we would be able to detect antimatter clusters, or similar, based on emission lines but I'm not 100% on that. Huge annihilation events from colliding galaxies and clusters would have massive energy signatures unlike anything else but the frequency of this would determine how likely it would be to see the evidence.

[-] barsquid@lemmy.world 1 points 5 months ago

Don't colliding galaxies mostly not actually touch? I thought there's so much space between everything it's almost entirely gravitational interactions. I'd assume almost no huge annihilation events from that, or extremely low frequency.