Ummm. OK.
In a series for the Discovery Channel the renowned astrophysicist [Stephen Hawking] said it was "perfectly rational" to assume intelligent life exists elsewhere.But he warned that aliens might simply raid Earth for resources, then move on.
"If aliens visit us, the outcome would be much as when Columbus landed in America, which didn't turn out well for the Native Americans," he said.
Prof Hawking thinks that, rather than actively trying to communicate with extra-terrestrials, humans should do everything possible to avoid contact.
He explained: "We only have to look at ourselves to see how intelligent life might develop into something we wouldn't want to meet."
Ouch.
Read more about Hawking's upcoming television special from the BBC.
Stephen Hawking, of course, is the author of A Brief History of Time and the mastermind behind the Theory of Everything.