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Could matter-anti-matter repulsion power the expansion of the universe?

If matter and anti-matter were created in roughly equal proportions at BB, and their subsequent annihilation did NOT occur, perhaps if the left hemisphere was matter and the right hemisphere were anti-matter, would not the repulsive gravity of the two perhaps power the accelerating status of our "matter universe"? Matched by an equal condition on the anti- side?

No, because there is no repulsive gravity between matter and anti-matter. Anti-matter particles are basically the same as their corresponding matter particles, but they have opposite charge. They still attract each other gravitationally.

But even if matter and anti-matter did repel each other, your scenario still wouldn't work, given the way the universe is expanding. The universe expands such that every point in space is expanding away from every other point in space. Galaxy A is moving away from Galaxy B and Galaxy C, and Galaxy B and Galaxy C are also moving away from each other. If you had two flavors of matter (matter and anti-matter), and they repelled each other, but attracted themselves, then this wouldn't work. It doesn't explain the expansion of the universe as we actually see it.

May 2003, Christopher Springob (more by Christopher Springob) (Like this Answer)

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