***Atheists only!!!*** Your thoughts on the beginning of the universe?

Some people believe that there was a universe before the big bang that was contracting that led to the current universe. The matter just flew past each other instead of contracting. But as all the theories about the universe break at the Big Bang so it doesnt matter what the other universe was like as it would have no impact on the current one. Also we cant use the current universe to determine the earlier universe with the theories that we have now. But again, this is also a theory.