I know what Einstein said, he said it’s the best religion of all that can cope with modern science. This is true, because it doesn’t have a divine god nor does it accept the theory of creationism and all that non sense. On top of that it is a very practical religion. But that is not the point. IMO coping up with science doesn’t make it science. One might argue that it does, but I’m just telling my opinion.
About the big bang theory: recent Buddhist scientists and monks are trying to fit some of the high level concepts of buddism to interpret the big bang theory. But it is just an interpretation.
The interpritation most people point out is the four divisions of time explained in the
Anguttara nikaya, Agganna sutta:
Samvattakappa : in which the universe dissolves,
Samvattathayikappa : in which the universe remains in a state of emptiness
Vivattakappa: in which the universe comes in to existence
Vivattathayikappa : in which the universe remains in a steady state
These four stages have been interpreted by some to explain the expansion and contraction phases of the BigBang theory, but it is JUST an interpretation and not an explanation. Correct me if I'm wrong but I don't think it says about an expanding universe per se and it doesn't explain the Big bang theory at all. Try to understand the difference between trying to fit some vague ideas into an existing theory and actually explaining it.
I don't know abhidharma so I could be wrong. If anyone have a better understanding please comment.