3 ms·
> it could exist in issolated-enough patches of the Universe. Photons, gravitational waves or neutrinos coming from those regions would not differ in any way, s
by breuleux 5y ago
> it could exist in issolated-enough patches of the Universe. Photons, gravitational waves or neutrinos coming from those regions would not differ in any way, so we would not be able to identify those regions, up until they merge with normal-matter-filled ones
Interesting. So how do we know there actually is more matter than antimatter in the universe? Couldn't there be a roughly equal number of sufficiently isolated pockets of each?
- Sharlin 5y agoIt is a well-known hypothesis, but space is not empty enough for it to be consistent with observations at least within our observable universe. If there really were antigalaxies or anticlusters out there, we would expect to observe characteristic gamma ray photons from the matter–antimatter boundaries where the extremely sparse but still existing intergalactic medium would interact and annihilate.
- ncmncm 5y agoPeople have looked for evidence such annihilations, but the observations we have are not able to rule them out. Antimatter superclusters (of clusters of antimatter galaxies) remain very possible. Nobody wants to talk about them because they don't want to be ostracized for speculating on what cannot be settled by evidence. But people do check, now and then, when new information comes up.
- ncmncm 5y ago... It must be said, too, that nobody has identified any way for the antimatter to have become so far separated from the regular matter. All the processes we know of that make matter like to make both (exactly) equally.