British physicist Stephen Hawking, the brilliant man who wrote "A Brief History of Time," says aliens probably exist and frets that if they discover Earth their intentions might be less like the film, "Close Encounters of the Third Kind" and more like the book, "A Hitchhiker's Guide to the Galaxy." In the book, alien bureaucrats determine the Earth should be demolished to make way for space highway and blow the Earth up. Sorry. Nothing personal. Prepare to die. It's not such a crazy thought, says Hawking, in a Discovery Channel series. "To my mathematical brain, the numbers alone make thinking...
