Stephen Hawking says that humans may one day be able to use time travel to skip generations into the future.
He has suggested humans could build spaceships capable of such high speeds that time itself would slow down for those on board. Such a spaceship could travel thousands of years into the future at close to the speed of light, reaching distant star systems within the lifetime of its crew.
He makes his comments in Stephen Hawking’s Universe, a documentary to be screened by the Discovery channel from next Sunday. A suggestion in another part of the series — that alien life is highly likely to exist but humans should try to avoid it — has already generated global interest.
Einstein found that as objects accelerate through space, the rate at which time passes for them slows down. For objects such as aircraft the effect is negligible, but Hawking’s spaceship would exceed 98% of the speed of light, when such effects would be extremely powerful.
Hawking said such a ship could theoretically reach speeds of more than 650 million miles an hour, but would have to be built on a huge scale simply to carry all the fuel that would be needed.
“It would take six years at full power just to reach these speeds. After the first two years it would reach half light speed and be far outside the solar system. After another two years it would be travelling at 90% of the speed of light,” he said. “After another two years of full thrust the ship would reach full speed, 98% of the speed of light, and each day on the ship would be a year on Earth. At such speeds a trip to the edge of the galaxy would take just 80 years for those on board.”
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