I've always been amused by fears of an alien invasion because it's based on the assumption of a united extraterrestrial species. I don't know why people make this assumption. As I recall first reading in the Animorphs series, there is only one known species that could organize an invasion of another planet - humans - and we spend our time waging war among ourselves.
We happily label each other aliens based on facts of birthplace or administrative processes. So why do we expect differently of Yoda or E.T.? Species unity seems a bigger advance than ray guns or space travel at light speed. I imagine our neighbors on Pluto look at us with the same repulsed fascination we reserve for militaristic ant colonies, and apply the same intervention strategy - watching these little idiots from afar will do just fine, thanks.
