July 7, 6:28 PM (ET)

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. (YHOO) users had responded.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 it is possible unless we expand into space," one user wrote.A number of people suggested thinking differently, ending bickering or fostering cooperation.

Officials at the University of Cambridge, where Hawking is a mathematics professor, confirmed that Hawking wrote the message but said he would have no further comment.

Hawking's groundbreaking research on black holes and the origins of the universe has made him one of the best-known theoretical physicists of his generation. Author of the global best seller "A Brief History of Time," Hawking is known for proposing that space and time have no beginning and no end.

Lately, he's been pondering about the fate of humans. In a June 13 speech in Hong Kong, Hawking said the survival of the human race depends on its ability to find new homes elsewhere in the universe because there's an increasing risk that a disaster will destroy Earth.

He said that if humans can avoid killing themselves in the next 100 years, they should have space settlements that can continue without support from Earth.
Hawking is one of 10 celebrity questioners Yahoo solicited as part of its "Ask The Planet" campaign.

The Sunnyvale, Calif., Internet company spent weeks trying to track Hawking down but got his participation within a day of reaching the correct assistant, said Patrick Crane, vice president of marketing for Yahoo Search.

The question was submitted a few days before the Hong Kong speech and posted this past Wednesday.

Over the next week, Yahoo employees are expected to work with Hawking to sift through the answers and select one or several to highlight as best responses.

Yahoo Answers, like an offering from Google Inc. (GOOG) and one planned by Microsoft Corp. (MSFT), is among the services aimed at tapping the collective intelligence. It's based on the premise that humans as a group can do a better job at finding information than machines or any single person can.

Anyone can ask or answer a question, regardless of expertise, although Yahoo will eventually implement a rating system meant to elevate users with better reputations, based on their past questions and answers.

Questions typically get 6 to 10 answers.

Past celebrity participants include Donald Trump, Isaiah Washington, Al Gore and "Click & Clack," the hosts of NPR's "Car Talk." U2 lead singer Bono closed the celebrity series Friday by asking, "What can we do to make poverty history?"
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On the Net:
Hawking's question:
http://answers.yahoo.com/my/profile?show=c32ad6278ed171cdd5089f4021da47a9aa

Bono's question:
http://answers.yahoo.com/question/?qid=20060706201547AAy10c8&pa

Hawking's site: http://www.hawking.org.uk