AN ANSWER TO THE FERMI PARADOX: Humans May Be The First Generation of Advanced Life In The Milky Way.

That would actually be good, since if aliens exist, they probably want to destroy us.

I recommend this piece by Gregg Easterbrook. Key bit:

James Trefil, of George Mason University, has cautioned that if evolution functions approximately the same way on other worlds that it has functioned here — conferring survival upon the fittest — advanced extraterrestrials might still be aggressive, territorial, and quick to reach for the sword. In that case, counting on poor alien marksmanship might not be prudent. Even if a message arrived from a great distance, we might for defensive reasons be compelled to assume that the senders knew something about the speed-of-light barrier that we didn’t, and withhold our reply.

The most disquieting aspect of natural selection as observed on Earth is that it channels intellect to predators. Most bright animals are carnivores: stalking requires tactics, pattern recognition, and, for social animals, coordinated action, all incubators of brainpower. Though the martial heritage of mankind has been exaggerated in popular fiction (there’s no proof, for example, that our Cro Magnon ancestors waged war against the vanished Neanderthals), it’s reasonably certain that the forebears of modern Homo sapiens were hunters, and it’s definite that man has been savage during the historical era. This isn’t much of a testimonial to “intelligence.”

Well, not as tending to nonviolence. On alien invasions generally, a good fictional treatment is in Greg Bear’s The Forge Of God, For the more technically-inclined, there’s Ernst Fasan’s Relations With Extraterrestrial Intelligences, or some chapters in McDougal, Lasswell, and Vlasic’s Law and Public Order In Space. Kind of old, but still good. A more recent popular treatment that’s worth your time is Ben Bova and Byron Preiss’s Are We Alone in the Cosmos? The Search for Alien Contact in the New Millenium.

if aliens just don’t like us, there’s no need to invade. They could send a half-pound of deadly nanodevices on a stealthed probe. We probably wouldn’t even recognize what was happening as an alien attack.