Scientific progress is almost certain to bring disaster to planet Earth within the next few thousand years, according to top cosmologist Professor Stephen Hawking.
He predicts that as new technologies are developed, the number of threats to the human race will increase until some kind of global cataclysm is virtually inevitable.
In the time period before humans manage to escape to the stars, they will have to be "very careful", he says.
Hawking's warning came during a question and answer session at the BBC Reith Lectures at London's Royal Institution on January 7.
His prophesy of doom came when a member of the audience asked him: "Do you think the world will end naturally or will man destroy it first?"
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The professor, research director at Cambridge University's Department of Applied Mathematics and Theoretical Physics, replied: "We face a number of threats to our survival from nuclear war, catastrophic global warming, and genetically engineered viruses.
"The number is likely to increase in the future, with the development of new technologies, and new ways things can go wrong.
"Although the chance of a disaster to planet Earth in a given year may be quite low, it adds up over time, and becomes a near certainty in the next thousand or 10,000 years.
"By that time, we should have spread out into space, and to other stars, so a disaster on Earth would not mean the end of the human race.
"However, we will not establish self-sustaining colonies in space for at least the next hundred years, so we have to be very careful in this period."
Most of the threats the human race faces come from progress in science and technology, he said.
