After saying last week that intelligent extraterrestrials almost certainly exist and Earthlings should avoid making contact with them, Cambridge University astrobiologist Stephen Hawking now says that it is possibly for humans to travel millions of years into the future - but not into the past.
Hawking, famous for his book A Brief History of Time, theorises that spaceships could, at some point in the future, travel at such huge speeds that time slowed down for those on board but not, say, for people back on Earth (although it could take as long as six years to reach 98% of the speed of light).
However, Professor Brian Cox, former keyboard player of pop band D:Ream and now a Manchester University physicist who recently hosted the popular BBC documentary Wonders of the Solar System, admitted there were significant impediments to realising Hawking's theories, although he backed the Cambridge scientist.
Hawking backs possibility for humans to travel millions of years into the future
By Scott Warren
2nd May 2010
Daily Mail
Stephen Hawking has claimed that humans might one day be able to use time travel to skip generations into the future.
The famous astrophysicist, speaking in a new documentary, said spaceships could one day be capable of such high speeds that time slowed down for those on board.
He admitted he had avoided talking about time travel previously ' for fear of being labelled a crank', saying the subject had once been 'scientific heresy'. 'These days I'm not so cautious,' he said.
Big ideas: Stephen Hawking believes humans are capable of time travel
Theoretically, such a space ship would allow the crew to repopulate the earth if they found our species had become extinct during their flight.
Stephen Hawking's Universe, in which he makes the comments, will be screened on Discovery next Sunday. In another part of the series he says alien life is likely to exist but that humans should avoid making contact.
Hawking said a spaceship capable of travelling through time - but only forwards - would breach Albert Einstein's theories of relativity.
Having taken six years to reach its full speed of 98 per cent of the speed of light (650million miles per hour), a day on board the ship would be equivalent to a year on Earth, he said, allowing those on board to reach the edge of the galaxy in just 80 years.
But the ship required for the journey would have to be massive to allow for the required fuel.
He dismissed the idea of travelling backwards through time, saying doing so would violate a fundamental rule that cause comes before effect and that such an act could allow people to make themselves impossible, such as if a person travelled back in time and shot their former self.
While backing Hawking's theories, Brian Cox, a Manchester University professor and the presenter of BBC's Wonders of the Solar System, admitted there were significant impediments to realising them.
'We can already see how time slows down for objects travelling at high speed by looking at what happens in paricle accelerators,' he told The Times.
Professor Brian Cox
'When we accelerate tiny particles to 99.99 per cent of the speed of light in the Large Hadron Collider at Cern in Geneva, the time they experience passes at one-seventhousandth of the rate it does for us.
'If we could build a spaceship that was fast enough, then it could reach other stars in the lifetime of the crew, but maybe 2.5million years would have passed by on earth.'
dailymail.co.uk
Hawking, famous for his book A Brief History of Time, theorises that spaceships could, at some point in the future, travel at such huge speeds that time slowed down for those on board but not, say, for people back on Earth (although it could take as long as six years to reach 98% of the speed of light).
However, Professor Brian Cox, former keyboard player of pop band D:Ream and now a Manchester University physicist who recently hosted the popular BBC documentary Wonders of the Solar System, admitted there were significant impediments to realising Hawking's theories, although he backed the Cambridge scientist.
Hawking backs possibility for humans to travel millions of years into the future
By Scott Warren
2nd May 2010
Daily Mail
Stephen Hawking has claimed that humans might one day be able to use time travel to skip generations into the future.
The famous astrophysicist, speaking in a new documentary, said spaceships could one day be capable of such high speeds that time slowed down for those on board.
He admitted he had avoided talking about time travel previously ' for fear of being labelled a crank', saying the subject had once been 'scientific heresy'. 'These days I'm not so cautious,' he said.
Big ideas: Stephen Hawking believes humans are capable of time travel
Theoretically, such a space ship would allow the crew to repopulate the earth if they found our species had become extinct during their flight.
Stephen Hawking's Universe, in which he makes the comments, will be screened on Discovery next Sunday. In another part of the series he says alien life is likely to exist but that humans should avoid making contact.
Hawking said a spaceship capable of travelling through time - but only forwards - would breach Albert Einstein's theories of relativity.
Having taken six years to reach its full speed of 98 per cent of the speed of light (650million miles per hour), a day on board the ship would be equivalent to a year on Earth, he said, allowing those on board to reach the edge of the galaxy in just 80 years.
But the ship required for the journey would have to be massive to allow for the required fuel.
He dismissed the idea of travelling backwards through time, saying doing so would violate a fundamental rule that cause comes before effect and that such an act could allow people to make themselves impossible, such as if a person travelled back in time and shot their former self.
While backing Hawking's theories, Brian Cox, a Manchester University professor and the presenter of BBC's Wonders of the Solar System, admitted there were significant impediments to realising them.
'We can already see how time slows down for objects travelling at high speed by looking at what happens in paricle accelerators,' he told The Times.
Professor Brian Cox
'When we accelerate tiny particles to 99.99 per cent of the speed of light in the Large Hadron Collider at Cern in Geneva, the time they experience passes at one-seventhousandth of the rate it does for us.
'If we could build a spaceship that was fast enough, then it could reach other stars in the lifetime of the crew, but maybe 2.5million years would have passed by on earth.'
dailymail.co.uk
