|
|
|
|
|
|
by nonameiguess
1065 days ago
|
|
|
As far as models model, most of the regular matter did annihilate. If I'm remembering correctly, the fact that anything we can see and feel still exists is an asymmetry between matter and antimatter somewhere in the arena of 30,001 particles for every 30,000 antiparticles. Obviously, very nearly all of this annihilated, and all of the matter that still exists is the residue of this early asymmetry. I don't exactly keep up to date on this stuff, but this either was or still is one of the bigger open questions regarding the Big Bang. What caused this asymmetry? It was one of the classic examples of apparent fine tuning. As for why dark antimatter/matter pairs would persist longer rather than run out (I guess that's the opposite of what you're saying, but it's important to remember what we're seeing even looking back this far is way after the normal matter/antimatter annihilated immediately after inflation), it's effectively the same reason dark matter doesn't clump and retains it's roughly spherical form at larger than entire visible galaxy sizes. Regular matter interacts via the electromagnetic force, which has an infinite interaction radius. Charged particles repel and attract each other from large distances. Thus, fundamental particles don't need to get that close to each other to form atoms and molecules. Dark matter only interacts via the weak force, which has a tiny interaction radius. The fundamental particles need to more or less make a direct beeline to the same point in spacetime to ever touch each other, which has an extremely low probability of ever happening. It's the same reason Earth can be bombarded nonstop with unimaginably large numbers of neutrinos every second from the sun, yet virtually all of them go straight through everything. All of space is mostly empty space, even things that look solid to us because the wavelengths we can discriminate are much larger than the spaces between atoms and molecules. It wouldn't look that way to dark matter. It would look actually empty. |
|
|
And gravity, or so I'm told.
But both gravity and the weak force are fields, and so just like EM, they pervade space. Isn't that right? The weak force weakend dramatically with distance, but it doesn't disappear - I thought one property of a field is that it pervades spacetime.
Not that that makes any difference to your argument.