Second to evolution in controversy is cosmology.

Cosmology as a field of science sounds like it is stomping hard on religion's turf by trying to explain why the universe exists. The purpose of cosmology is to examine the structure, size, shape, and distribution of stuff in the universe. These questions extend in space and in time (actually in spacetime, but relativity is a whole other subject). We cannot look forward in time to see future distributions, but thanks to the fact that our primary means of perceiving (light) moves at a fixed speed (300,000km/second), we are constantly receiving messages from the past that allow cosmologists to chart backwards in time and discern earlier stages of the universe.

One of the things that can be discerned as we look back in time is that the universe was smaller at earlier times. The farther back we look the smaller it gets. There is a point around 13.5 billion years ago when all the universe seems to have been at a single point.

We can't actually see back to that point. We can see back to just after that point, and using theories that work well in other circumstances we can deduce a great deal of what was going on just after that moment (the Big Bang).

The moment of the Big Bang and anything that might have happened before it are so far not matters to which science can be directly applied. In a sense therefore the primal event is not a matter of science. And the causes of that event are purely hypothetical at this moment because there is no discerning what there was beforehand.