‘Where are they?’, asked Enrico Fermi decades ago. He meant all the aliens, of course. Apparently, the sky is empty of them, but why? Did they all die or what? Have they ever lived?
As Marshall T. Savage put it:
Scientists huddle around radio telescopes listening intently to one star at a time for the sound of dripping water, when what they are seeking would sound like Niagara Falls.
We have a major bookkeeping imbalance to correct. So many stars and planets on one side, and so few space travelers and space conquerors on the other.
Maybe, there’s also too much water in space.