Some people say the existence of aliens can fit with the Book of Genesis because the Book of Genesis, they say, only describes the creation of earth and the human race not of the whole universe.
But the Book of Genesis describes the origin not only of the earth but of "the heaven and the earth". That means the universe, doesn't it? It also describes the origin not only of our solar system but of the stars. Stars exist outside our solar-stystem.
Not only that, but the Bible describes the reason why all the heavenly bodies were made. They were made for earth's benefit - to give light, to mark time and seasons, etc. It doesn't say they were made to be the home of aliens.
But even if the Book of Genesis is only meant to be about what concerns us in our part of the universe, the Bible as a whole describes everything that can have a causal relationship with mankind here on earth.
So I would say the existence of aliens can fit with the Bible only if they exist in another universe that is not capable of ever having a causal relationship with our universe. In which case, we should never see any aliens - not in the past, present nor in our future!
However, I don't think the concept of multiple universes is possible - because the very word 'universe' is meant to describe everything that exists. So I think the existence of aliens is unlikely.
I often say that if their existence starts impacting on my life practically, that's the time I'll start responding to their existence. But in the meantime, I'm happy to stick with Biblical revelation as I currently understand it.
