Like Dawkins (http://www.rawstory.com/rs/2013/09/25/dawkins-humanity-has-a-50-percent-chance-of-surviving-until-the-next-century/), I'm not at all sure the human race, or at most, our advanced technological civilization, will survive past this century. There is some evidence, in Hindu writings and in scattered ancient ruins, that we may have approached these technological heights in the distant past, only to destroy it all and almost wipe ourselves out through nuclear war that it took millenia to recover from.
I know, those are mythological accounts no more reliable in many respects than the Bible is. But, sometimes there is a germ of truth behind the mythology, just as the destruction of Sodom and Gormorrah likely did occur from an asteroid impact. Then, the myth builders took over and distorted it beyond all recognition. I suspect the story of Lot is just like the story of the exodus -- a total concoction.
I know, I drive some of you biblical believers insane with statements like that. I'm a literalist, not a faithest these days. Been there, done that. It was a crock!
He made an interesting point I've also considered. That point being that we may not find any advanced civilizations in the rest of the universe due to the fact that they may destroy themselves about the time they reach a level comparable to ours. It only takes one among many fanatic minorities in a society to bring about civilization-destroying cataclysm. We have a multitude of those in both the political and the religious spheres. One of those fanatics just spent 21 hours shooting off his stupid mouth in our nation's capitol! His ignorant, hate-filled compatriots are holding the entire government hostage to their insane demands!
I'll still hope, but I seriously doubt, when I look at things coldly, that our chances are really 50-50. I think they're much more pessimistic than that.