In a recent blog post, NBC News science editor Alan Boyle pretty much destroys that idea.
"NASA's Kepler planet-hunting mission suggests that there could be billions upon billions of alien Earths and super-Earths out there. "What is it we have to offer, aside from some pretty good fish up in Seattle?" Shostak asked NBC News. "The answer is, not much. Just our culture, really. That's the only thing that they won't have at home, where the shipping charges are less."
"Shostak complained that the standard motivations have become terribly outdated: "They come here for the water, or they come because something is wrong with their reproduction. People love that sex angle. But I'm not going to go to the insects in the backyard because things have gone wrong with our reproduction - and those guys, at least, have DNA. Most of this doesn't make any sense whatsoever."
"The aliens could be in it for the cultural exchange. Or they might just dig the music, like the clueless extraterrestrials in Rob Reid's comic novel about contact, "Year Zero." But if they come in with ray guns blazing, they'll spoil the atmosphere, in more ways than one."
Read more here.
There are also some stories where aliens come to earth to enslave the populace but those stories also don't stand up to a basic logic test. These are, in theory, aliens capable of interstellar travel. Humans, who are still far from that level of technology are on the verge of not needing workers anymore. The current state of robotics and AI are such that we can automate almost any job. Why would aliens travel half way across the galaxy to gather slaves who will require security, food and shelter when they could simply stay home and build robots?
Alien invasion stories are fun, but the reality is that if visitors from another world ever drop by it will probably be to say hello. There is no logical reason for alien visitors to attack, unless, of course, we act like humans and shoot first.
