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SpaceGuy50
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Can there be stars and planets made out of antimatter?
protonchain said:There's no presence of anti-matter in the universe. Any production of antimatter (say in the proton proton chain) usually interacts with regular matter and produces gamma ray energy, annihilating both particles.
mgb_phys said:Obviously there aren't any anti-matter objects nearby but if you had a distant galaxy composed of antimatter it wouldn't have any matter to react with.
There would be a matter-antimatter front where interactions would occur but the particle density of intergalactic space is only 1atom/few 10s of m^3 so you wouldn't expect much signal.
I can't remember what the observable limits are, but all sky X-ray surveys aren't all that sensitive.
protonchain said:However it was completely annihilated (the specific term is baryogenesis) as the universe exited the lepton epoch, big bang nucleosynthesis had occurred and the universe had reached the photon-dominated era (photon-dominated vastly due to annihilation).
Obviously the reason why matter (baryons) dominated over anti-baryons is still a big mystery as this is peering well before the surface of last scattering and is mostly theoretical, but there's no observational evidence currently for any undisturbed anti-matter in the present universe we all know and love.
Redbelly98 said:If it's not observationally ruled out, why is there consensus that the universe is primarily made of matter?
We can only deal with the observable universe. The observable universe is our universe.SpaceGuy50 said:Exactly. We can only see billions of light years, which is a pretty tiny part of a perhaps infinite universe.
Our galaxy is matter (by definition), where matter and anti-matter meet you get annihilation and a characteristic x-ray signal. At some point in the space between them the inter stellar medium from the matter galaxy would meet the ISM from the anti-matter galaxy and go bang. It's rather like having two continents with different religions - where they meet you would have a thin strip of land where people are constantly at war.Sidnv said:How did we actually prove that the universe is dominated by matter and not anti-matter?
There are no identifiable x-rays in matter-antimatter annihilation of proton and anti-protons.mgb_phys said:Our galaxy is matter (by definition), where matter and anti-matter meet you get annihilation and a characteristic x-ray signal. We don't see any such x-ray signal, however the ISM is very thin (very few particles/m^3) in the space between galaxies so it isn't completely ruled out.
The biggest argument against it is that we detect cosmic rays from other (nearby) galaxies and they are matter. We can also see the signal from the early universe when things were very much closer together and presumably any matter-antimatter interaction would be more common.
Galaxy clusters are surrounded by hot ionized gas with a temp of tens of millions of degrees. so it seems reasonable to assume that if an antimatter cluster were next to a matter cluster that there would be a lot of annihilation occurring at the boundary between them.mgb_phys said:Obviously there aren't any anti-matter objects nearby but if you had a distant galaxy composed of antimatter it wouldn't have any matter to react with.
There would be a matter-antimatter front where interactions would occur but the particle density of intergalactic space is only 1atom/few 10s of m^3 so you wouldn't expect much signal.
I can't remember what the observable limits are, but all sky X-ray surveys aren't all that sensitive.
1] Uh, what direction is matter moving such that antimatter would move in the opposite direction?dextor said:I fine the concept of anti-matter interesting. If anti-matter were to exist, won't it be going in the opposite direction of the matter?
DaveC426913 said:We can only deal with the observable universe. The observable universe is our universe.
Well, me and serious scientists.fillindablank said:The observable universe is YOUR universe Dave. Not everyone limits themselves like that.
kingkong01 said:it is thought that the big bang was caused by anti matter comeing into contact with matter which caused an explosion as thay made contact. so this is thought to prove the existence of anti matter
kingkong01 said:it is thought that the big bang was caused by anti matter comeing into contact with matter which caused an explosion as thay made contact.
kingkong01 said:so this is thought to prove the existence of anti matter
Antimatter is a form of matter that has the same properties as regular matter, but with opposite electric charge. For example, an antimatter electron, or positron, has a positive charge instead of a negative charge like a regular electron. When matter and antimatter come into contact, they annihilate each other and release a large amount of energy in the form of light.
It is currently unknown if stars and planets can be made entirely out of antimatter. However, it is theorized that in the early universe, there may have been equal amounts of matter and antimatter, and some regions of the universe may have been dominated by antimatter. These regions could have formed stars and planets made of antimatter in the same way that regular matter forms them.
It is highly unlikely that humans could survive on a planet made of antimatter. When matter and antimatter come into contact, they annihilate each other, releasing a tremendous amount of energy. This would make the planet inhospitable for life as we know it.
One way to detect a planet or star made of antimatter is through its interactions with regular matter. When matter and antimatter come into contact, they produce gamma rays, which can be detected by telescopes. Scientists are also looking for imbalances in cosmic rays, which could indicate the presence of antimatter in the universe.
Currently, there is no concrete evidence of stars or planets made of antimatter in the universe. However, scientists are constantly searching for signs of antimatter through experiments and observations. Some theories suggest that there may be small regions of the universe where antimatter dominates, but more research and evidence is needed to confirm this.