The discussion revolves around the observation and theoretical understanding of antimatter in the early universe, specifically addressing the ratio of particles to antiparticles and the implications of this ratio for the universe's evolution. Participants explore concepts related to the Big Bang, energy production, and the nature of matter-antimatter asymmetry.
Participants express differing views on the assumptions regarding the equality of matter and antimatter production, the interpretation of energy sources, and the implications of the observed ratios. The discussion remains unresolved with multiple competing perspectives presented.
Limitations include the lack of direct observational evidence for the proposed ratios and the dependence on theoretical models that may not fully account for all variables in the early universe.
That estimate comes from comparing the total amount of energy in the universe with the total amount of matter. If we assume that matter and antimatter were created in approximately equal amounts at the big bang, and then all the antimatter annihilated with matter to produce energy... we conclude that the universe started out with one billion and one particles for every billion antiparticles (which certainly qualifies as "approximately equal amounts") and then the antiparticles and particles paired off and annihilated leaving behind only the extra one in a billion particle - and these make up all the matter we observe.KarminValso1724 said:I have heard before that for every 1 billion antiparticles there are 1 billion and 1 particles of normal matter. Has this been observed directly or just predicted? Have we only observed antimatter through its creation on earth?
That is a good question for which, as far as I know, science doesn't have a completely satisfying answer. However, you'll find better answers over in the Cosmology subforum where the people who are up to date on this stuff hang out.mrspeedybob said:Why wouldn't the matter / antimatter production be exactly equal?
We don't assume it, we infer it from the amount of energy that we observe. If for every particle we find energy sufficient for one billion particle/anti-particle pairs, that leads to the billion-plus-one to billion ratio OP is asking about.And if wasn't exactly equal, why would we presume that it was approximately equal?
We have calculated rates of particle and anti-particle creation shortly after the big bang, so we know (very roughly - that "one billion" number is not exactly a rigorously specified quantity) how many particles had to have disappeared in annihilations.mrspeedybob said:But why do we think the energy came from particle/antiparticle annihilation? Why does it make more sense to say there were 2 billion + 1 particles and 2 billion of them annihilated to become energy, instead of saying there was 2 billion +1 units of energy and 1 of them condensed into a particle? Or maybe 3 of them condensed and 2 annihilated, which would make matter/antimatter production 2 to 1. Or really pick any ratio?