As part of a new Discovery Channel series physicist Stephen Hawking says that he's convinced aliens are out there, but that we should avoid them because they will probably come to earth and kick our asses like in the movies.
The Times of London report Hawking's theory that intelligent extra-terrestrial life is mathematically very probable. And that we should be building alien shelters. "We only have to look at ourselves to see how intelligent life might develop into something we wouldn't want to meet," he said. "I imagine they might exist in massive ships, having used up all the resources from their home planet. Such advanced aliens would perhaps become nomads, looking to conquer and colonise whatever planets they can reach."
"If aliens ever visit us," he added, "I think the outcome would be much as when Christopher Columbus first landed in America, which didn't turn out very well for the Native Americans." So watch out for any spacecraft called the Nina, the Pinta or the Santa Maria.