0
$\begingroup$

Can it be possible that in the big bang, not one, but two universes were formed, one formed of matter, and the other formed of antimatter? It seems logical to me that since our universe is formed of matter, there must be some universe made of antimatter, so that a sort of an equilibrium is maintained. Can this other antimatter universe be treated like a mirror image to our universe, so as to maintain the equilibrium?

Actually, to me it seems a bit strange that the big bang should produce a universe with much matter and little antimatter. So it seems that there must be a universe with greater antimatter and less matter, just the mirrored image of our universe, doesn't it?

$\endgroup$
5
$\begingroup$

There are various theories about how the matter anti-matter asymmetry arose. See this search for lots of related questions. It's generally believed that the Big Bang formed almost equal quantities of matter and anti-matter, but there was a very small inbalance i.e. there was slightly more matter. The anti-matter all annihilated with matter to leave normal matter and lots of photons (the particle to photon ratio in the universe is about $10^{-9}$, that is a billion photons for each particle of matter).

Over the years various ideas have been proposed, for example that some areas of the universe contain matter and other areas contain anti-matter. However no-one has ever come up with a convincing theory to describe how this could happen. You suggest there could be an anti-matter universe, but you'd need to put this on a sound mathematical footing for anyone to take the suggestion seriously, and no-one has ever managed to do this.

By contrast the suggestion I mentioned in my first paragraph is theoretically plausible, though the exact mechanism for generating the small excess of matter is unknown. It requires a process known as CP violation, and this is known to happen and has been measured at accelerators. However the amount of CP violation we've measured is too small to account for all the matter we see. It's widely believed that when we understand physics beyond the Standard Model, be it String Theory or whatever, we'll discover how the excess of matter originated.

$\endgroup$
-1
$\begingroup$

A universe is by definition all there is, so there is only one of 'em. Yet be my guest to imagine any number of them as long as they are disconnected from the one we are actually in.

$\endgroup$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.