“To think out of billions and billions of galaxies we’re the only one with life?”
Some day we may discover there is life elsewhere in the Milky Way or we may not. But the Milky Way only represents a small fraction of the universe.
Our nearest real galaxy (the way I think of them) is Andromeda which is 2.5 million light years from us. We may never know if life exists or not in our nearest galaxy much less the other 2 trillion galaxies out there.
Thus I don’t believe we could ever state that Earth has the only life in the universe.
The reality is that it doesn’t really matter if there is or is not life on the other 2 trillion galaxies out there because they are so far away as to be essentially irrelevant to our existence.
And pretty much isolated. We all may be gone in relationship with other galaxies, like we’re already gone by the time the light of our galaxy reaches them.