[rwallace]

It boils down to the deeply ingrained human psychological need to believe in higher powers, in a universe governed by the struggle between the forces of good and evil that are fundamentally human. The same thing happened with space exploration: as soon as we discovered - even conjectured - the existence of other worlds, the first thing we did was people them with imaginary elder civilizations. Real life threats don't fire the imagination to the same extent. Even if we end up going out in a nuclear war, it's more likely to happen by stupidity than malice.