What you are trying to convince yourself of, is the possibility. Not proof it has happened.
chances of us being the only life, ever in the universe - very highly unlikely.
chances of life existing elsewhere now - very likely
chances of them being substantially more advanced, perhaps able to live longer and more adapted to space travel?
- why not?
It is after all very, very big and its been around a while.
That is not to say they have been sighted and visited us. But the possibility is there.
did you read this ?
Description
www.nasa.gov