On the possibility of contact with an alien civilization:
I think it would be a disaster. The extraterrestrials would probably be far in advance of us. The history of advanced races meeting more primitive people on this planet is not very happy, and they were the same species. I think we should keep our heads low.
From an appearance in the National Geographic Channel program Naked Science: Alien Contact. As quoted in The New York Times (24 November 2004)