About Intelligent "Aliens" Existing? Aliens have been here and they are..."avoiding us"

[PoindexterOglethorpe]

17. Maybe there is one and only one intelligent life in each galaxy at any one time.

Think hard about just how old the universe is, and the odds of a technological civilization lasting any great length of time.

Even within our one galaxy, interstellar distances are such that it's probably completely impossible to travel to other stars, other than with generation ships. Between galaxies? Are you serious?

And, while at this point pretty much every single star we look at has planets (My Son The Astronomer is doing exoplanet research), the conditions in the center of the galaxy would probably make potential living conditions on planets there difficult at best. And keep in mind that the majority of stars, as in 85%, in this galaxy are red dwarfs, that means conditions on any planet in the habitable zone of a red dwarf would be very different that on our planet. Which means life, if it actually starts (and that's another huge unknown) would no doubt evolve vastly differently from the way it did here.

I also offer this to think about intelligent life. What if it evolves on a Jupiter? They might never make it to the upper edge of that atmosphere and see that there's a whole lot other stuff out there. Or on a Europa, a planet covered in ice? They'd have no clue there is anything else out there. Or if their vision evolves in a way that they simply don't see stars. Or somehow have no curiosity about the rest of the universe, are content to stay home and produce great works of their art and literature?

In short, I can think of a lot of reasons why intelligent life might well evolve, but never even try to visit us.

But I honestly think that the possibility of actual overlap of at least two technological civilizations is vanishingly small.