Stephen Hawking warned that future generations would need to leave the planet to ensure the survival of the species as he picked up a prestigious scientific accolade yesterday.
Professor Hawking, 64, a mathematics professor at the University of Cambridge, said space rockets using the kind of technology seen in Star Trek would be needed to colonise hospitable planets.
His warning came as he collected Britain's highest scientific award, the Royal Society's Copley Medal, previously granted to Charles Darwin, Michael Faraday and Captain James Cook. Professor Hawking, who suffers from motor neurone disease, said he was "honoured" to be in the company of such esteemed men.
The society's president, Lord Rees, said he had contributed "as much as anyone since Einstein to our understanding of gravity".
Professor Hawking also spoke of his desire to go into space, and appealed to the Virgin tycoon, Sir Richard Branson, who is planning a "space tourism" venture, to realise his ambition. "My next goal is to go into space. Maybe Richard Branson will help me," he said.
In an interview with BBC Radio 4, he said scientists may be within 20 years of reaching the prediction in his book, A Brief History of Time, that mankind would one day "know the mind of God" by understanding the laws governing the universe.
He added that this knowledge may be vital to the human race's continued existence. "The long-term survival of the human race is at risk as long as it is confined to a single planet.
"Sooner or later, disasters such as an asteroid collision or nuclear war could wipe us all out. But once we spread out into space and establish independent colonies, our future should be safe. There isn't anywhere like the Earth in the solar system, so we would have to go to another star.
"If we used chemical fuel rockets like the Apollo mission to the moon, the journey to the nearest star would take 50,000 years. This is obviously far too long to be practical, so science fiction has developed the idea of warp drive, which takes you instantly to your destination. Unfortunately, this would violate the scientific law which says that nothing can travel faster than light.
"However, we can still within the law, by using matter/antimatter annihilation, at least reach just below the speed of light. With that, it would be possible to reach the next star in about six years, though it wouldn't seem so long for those on board," he said.
The cult science-fiction series, Star Trek, has featured matter/antimatter annihilation as an explanation for the warp drive which powers spaceships like the Enterprise through vast distances in short periods.
But in reality, some scientists believe the radiation produced when matter and antimatter are brought together could one day be used to accelerate aircrafts close to the speed of light.
Meanwhile, to recognise Professor Hawking's achievements, the British astronaut Piers Sellers carried his medal into space on the July shuttle mission.
"Stephen Hawking is a hero to all of us involved in exploring the cosmos. It was an honour for the crew of the STS-121 mission to fly his medal into space," he said.