Steven Hawking says time travel possible

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cobl04

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He suggested humans could build spaceships capable of such high speeds that time itself would slow down for those on board.
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It could enable humans to "colonise the future".
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"I used to avoid talking about it for fear of being labelled a crank, but these days I'm not so cautious."
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"It would take six years [to reach 98% the speed of light]."
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"Each day on the ship would be a year on earth... a trip to the edge of the galaxy would take just 80 years for those on board."
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Hawking dismissed the prospect of time travel into the past, pointing out it would create the so-called mad scientist paradox, where a researched could travel back in time and shoot his past self, raising the question of who fired the shot?

Time travel possible, but only moving forwards, says Stephen Hawking | News.com.au

comes a week after he said aliens exist.

ridiculously fucking interesting. not sure i'd be willing to give up 80 years of my life to see the edge of the galaxy, though.
 
Does he have plans for such a spaceship? because if not, I thought that theory of time travel was pretty common knowledge
 
Even though I think the idea of time travel is fun, I doubt it could ever happen. If so, wouldn't we have someone walking around today saying, "I am from the year 2500"?
 
Even though I think the idea of time travel is fun, I doubt it could ever happen. If so, wouldn't we have someone walking around today saying, "I am from the year 2500"?

Thats one of the points Hawking makes. Only forward time travel would be possible. If you think about it, it makes perfect sense. Except the whole pesky fast spaceship business
 
Only forwards? With no going back...hmm, doesn't sound thrilling to me.
 
Thats one of the points Hawking makes. Only forward time travel would be possible. If you think about it, it makes perfect sense. Except the whole pesky fast spaceship business

It's not like Hawking's saying anything new here, didn't Einstein already say as much?
 
i just think the whole thing is insanely interesting. i would have thought we're a bloody long way off making a spaceship that can travel at speeds of 650 million m/hr.

i could talk about this stuff for days on end..
 
this no travelling backwards thing is based on this "grandfather paradox", i think, which is if you went back in time, killed your biological grandfather, then technically wouldn't you cease to exist?

you can't answer these questions, i just find the debate very interesting.

anyone remember that bloke, a few years ago, who got ridiculed for a speech where he kept saying "known and unknown"? it was something along the lines of "we want to know the unknown, but the unknown should remain unknown, if we know the unknown, that would be dangerous..."

he got ridiculed, but it made perfect sense. are we going to get to a stage where we know so much that it because dangerous and potentially fatal? why do we need to know what all that dark matter is? some things are better left unknown.
 
i just think the whole thing is insanely interesting. i would have thought we're a bloody long way off making a spaceship that can travel at speeds of 650 million m/hr.

He doesnt say that a spaceship capable of doing that is within reach though. Thats what i dont understand about the article
 
the paradox is more of a thought experiment to show why it will never be possible
 
you could always fly the spaceship in reverse and you might go back in time.

superman-18.jpg
 
someone must've gone back and killed the guy who posted that picture before he had a chance to post it
 
Certainly Hawking is not the only credible scientist who has spoken about the subject. It is theoretically possible to time travel to the past. Hawking is just a dissenter that it's plausible. Time travel to the future has already been, essentially proven (see: clock experiments/time dilation).

A grandfather paradox does not negate time travel to the past, because if you went back to change something, you would either not be able to change it (see: Novikov self consistency principle) or your very presence would cause a change that would create a new 'universe'.
(see: Hugh Everett's Many Worlds theory)

If you want to know more about how time travel to the past is theoretically possible read about 'traversable wormholes'. It would require something that held the wormhole open, like exotic matter and then you spin one end behind the other in spacetime and that's one layman way of saying it...haha.

Plausible? Not very. This is why Hawking doesn't consider it.
Theoretically possible according to our current understanding? Believe it or not, yes.
 
It's a little like the time-travel potential of wormholes... there are some principles that 'work', but physical feasibility?

As for a spaceship, well if you accelerated by many, many stages over a period of years, yes I suppose, in principle, you might attain some fraction of the speed of light (if you could get a hold of enough reaction mass because you certainly wouldn't be taking that with you).

Absent wormholes or something even loopier, interstellar society will never be economical. This isn't like the American 'New World'.

Still, I agree with Stephen Hawking on the relatively uncontroversial observations that aliens 'might' exist somewhere in a universe of some billions of galaxies and trillions of stars, and that general relativity works.
 
i agree KMac, the aliens thing makes sense, especially if you look at it from purely a numbers perspective. we're one of trillions of planets, surely there is at least one other form of life out there.
 
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