The assertion that we’ve made, that God is the best explanation for the cause of the universe, is commonly called the Cosmological Argument. A popular atheist response to the Cosmological Argument is this: If everything requires a cause, then so must God.
However, the Cosmological Argument doesn’t say “everything has a cause,” but, “everything that has a beginning has a cause.”
We maintain that God does not have a beginning. By definition, He is an eternal being. Therefore He's “outside of time” and and outside of our physical world. God would have to have these transcendent qualities in order to be in a position create our universe.