Question

WHERE DID ALL THE ANTIMATTER GO?

Answer 1

Antimatter, which was created out of energy along with matter in the immediate aftermath of the Big Bang, annihilated in collision with matter for the last time as the universe expanded and cooled to a temperature below which matter and antimatter could no longer emerge from the cooling radiation field.

If an equal amount of matter and antimatter were being created at the time, then all that stuff would have become pure cooling energy..However for some reason 1 part in a billion of matter over antimatter was being created. So, that 1 part in a billion +1 matter particles makes up the vast majority of all the stuff in the universe today…the one billion particles which did annihilate fill the universe today as radiation with a temperature of 2.7K degrees.