Posted: Apr 24, 2013 3:03 pm
trubble76 wrote:Evolving wrote:Even by dint of looking billions of years back in time through the strongest telescopes, we're not going to succeed in observing the universe before the process of matter-antimatter annihilation was finished. The furthest we can look back is the last scattering surface about 300,000 years in (and what we see there is the cosmic microwave background radiation), whereas the mutual annihilation of particles and anti-particles would have been effectively over in the first second or so after the Big Bang.
If you are saying that the process of annihilation is over, then you are saying that there are no antimatter stars, are you not?
Yes, and I was conscious when typing it that I was begging a question in doing so, or at least giving an incomplete reply.
The answer to that begged question is what I wrote in my first response:
.it's hard to see why the opposite mechanism would have applied elsewhere in the universe
In other words, for the annihilation not to have been over everywhere in the first second, there would have to have been regions in which the annihilation produced a net anti-matter surplus by the end of that second, alongside the regions with the familiar matter surplus, and then the expansion of the universe would have to have happened too quickly for those regions to encounter each other.
Theoretically possible, in principle, but as I said: hard to see why it would happen.