Physicist Hawking says survival depends on space colonies

HONG KONG -- The survival of the human race depends on its ability to find new homes elsewhere in the universe because of an increasing risk that a disaster will destroy Earth, world-renowned physicist Stephen Hawking said Tuesday.

Humans could have a permanent base on the moon in 20 years and a colony on Mars in the next 40 years, the British scientist told a news conference.

"We won't find anywhere as nice as Earth unless we go to another star system," added Hawking, who came to Hong Kong to a rock star's welcome Monday. Tickets for his lecture Thursday were sold out.

Hawking 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.

"It is important for the human race to spread out into space for the survival of the species," Hawking said. "Life on Earth is at the ever-increasing risk of being wiped out by a disaster, such as sudden global warming, nuclear war, a genetically engineered virus or other dangers we have not yet thought of."

The 64-year-old scientist -- author of the best-seller "A Brief History of Time" -- uses a wheelchair and communicates with the help of a computer because he has the neurological disorder amyotrophic lateral sclerosis, or ALS.

One of the best-known theoretical physicists of his generation, Hawking has done groundbreaking research on black holes and the origins of the universe, proposing that space and time have no beginning and no end.

However, Alan Guth, a physics professor at the Massachusetts Institute of Technology, said Hawking's latest observations were something of a departure from his usual research and more applicable to survival over the long term.

"It is a new area for him to look at," Guth said. "If he's talking about the next 100 years and beyond, it does make sense to think about space as the ultimate lifeboat."

But, he added, "I don't see the likely possibility within the next 50 years of science technology making it easier to survive on Mars and on the moon than it would be to survive on Earth."

Joshua Winn, an astrophysicist at MIT, agreed. "The prospect of colonizing other planets is very far off, you must realize," he said.

Hawking's "work has been highly theoretical physics, not in astrophysics or global politics or anything like that," Winn added. "He is certainly stepping outside his research domain."

Also Tuesday, Hawking said he is venturing into the world of fiction. He plans to team up with his daughter to write a children's book about the universe aimed at the same age group as the Harry Potter books.