“I think it is almost certain that a disaster, such as nuclear war or global warming, will befall the earth within a thousands years,” 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.
He remained optimistic that science and technological progress would eventually enable humans to move beyond the solar system and out into the far-reaches of the universe.
But if man should meet alien life on its journey into space, the consequences for humanity could be grave, Prof Hawking warned.
“If aliens decided to visit us, then the outcome might be similar to when Europeans arrived in the Americas. That did not turn out well for the Native Americans.”
Hawking was answering questions submitted by listeners to BBC Radio 4’s Today programme to mark his seventieth birthday.
