A Cambridge University professor has claimed that humans must learn to live on other planets to survive because there is an increasing risk that a disaster will destroy our Mother Earth.

Professor 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 if humans could avoid killing themselves in the next 100 years, he told a news conference in Hong Kong.

"It is important for the human race to spread out into space for the survival of the species," he 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." said Prof Hawking.

The 64-year-old scientist is the author of the global best seller A Brief History of Time. His work focused on the search for habitable worlds and intelligent life beyond the solar system, as well as theories about life's origins, ideas popularized in his best-selling 1985 novel, Contact, which was made into a film starring Jodie Foster.

Prof. Hawkins received a rock star's welcome when he arrived in Hong Kong. He will give a lecture on Thursday, 15 June.

(Xinhua News Agency June 15, 2006)