I sometimes ask a similar question about matter/antimatter symmetry, if the “tiny asymmetry” that gets used as an explanation for why any baryonic matter exist at all, could be explained by the antiparticles we should’ve annihilated with being on the other side of our cosmic event horizon.
I've often wondered the same thing. What if the entire universe is finite, but something like 1^(enormously large number) times larger than the observable universe? We could be this tiny speck of a backwater that's completely unrepresentative of the overall universe. The Big Bang itself could have been a minuscule local disturbance that took place in some small part of the overall universe which is trillions of times older.
Seems like a not bad idea. Especially if the antiparticles accelerated away before they could interact. But the two types of particles should be mutually attracted. They’d also have to appear in an organized way to avoid collisions with other particles.
Maybe there wasn’t a Big Bang, but instead a “large shearing”. Ie two “sheets” (like higher dimensional objects) started in contact with one another and moved apart/were pulled apart from one another. Before the shearing, lots of energy existed with little or no opportunity for massive objects to form. During the shearing the particles adhered to one sheet (for whatever reason) and the antiparticles the other.
A question I'm too amateur to resolve on my own is what if the Big Bang simply created two universes? One made primarily of "matter" and the other made of "anti-matter?"
What if the big bang was simply a Casimir event? The particles should have collided and annihilated, but didn't? The result being two new universes pulled into existence by the sudden inversion of entropy?
I think that depends on whether big bang was global event that created matter in the entire universe (then no, because it's too far) or local event that affected observable universe (then we could see the spacetime curvature caused by outside objects and even gravitational waves that are older than the age of observable universe).