“It is possible that the human race could become extinct but it is not inevitable. I think it is almost certain that a disaster, such as nuclear war or global warming, will befall the earth within a thousands years,” Professor Hawking, the Cambridge University cosmologist and theoretical physicist said.

“It is essential that we colonise space. I believe that we will eventually establish self-sustaining colonies on Mars, and other bodies in the solar system, although probably not within the next 100 years.”