NEW YORK (AP) -- Some questions even stump Stephen Hawking. The famed British astrophysicist and best-selling author has turned to Yahoo Answers, a new feature in which anyone can pose a question for fellow Internet users to try to answer. By Friday afternoon, nearly 17,000 Yahoo Inc. users had responded to Hawking. Hawking's question: "In a world that is in chaos politically, socially and environmentally, how can the human race sustain another 100 years?" Some of the answers were short -- "get rid of nuclear weapons" -- and others vague -- "Somehow we will." Many were doubtful: "I don't think...