If you can question the existence of god, then you may also ask the question, “Where are the Aliens?”
We are alone in the universe, this is a scary and most unlikely logic. It is as scary as the thought “we are not alone in the universe”.
We know a lot now about our universe, but we do not know all. We haven’t still confirmed the existence of extra terrestrial life in the universe. In this documentary famous astrophysicist Neil deGrasse Tyson asked the same question as most people do.