Hello wim, the original question that I wanted to ask goes along these lines:
Why does is the big bang considered the origin of the universe by the scientific community?
Why do they asume that the big bang is the origin of the universe?
While the big bang might have occurred, it is not the "origin" of the universe.
It at most is the origin of the expansion of matter through the universe.
Think about the universe as a huge infinite vacuum that contains matter...