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, world-renowned physicist Stephen Hawking said.

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 sold-out lecture in Beijing yesterday (June 19).

"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," Hawking said.

The 64-year-old scientist - author of the global best-seller "A Brief History of Time" - uses a wheelchair and communicates with the help of a computer because he suffers from a neurological disorder called 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.

Editor: Wing