Is it posible

[diggers15]

Will we ever be able to go back in time

[boink]

im speaking from a scientific point of view, the idea of time travel is fiction, but we still have to judge the possibilities with science

[jake-the-peg]

On the contrary, relativity does not say that backwards time travel is impossible.

Kip Thorne tried to show that it was and ended up finding that relativity does not actually preclude it.

It seems irrational, but then so does quantum physics. Most of the models involve intense fields and black holes and other exotica which is why I say I don't believe it will ever be possible for you or I to materialise "star trek" fashion in another time period.

Of course whether bing able to travel backwards in time would be usefull is another question entirely. If the many worlds conjecture is right our Universe constantly splits and divides between different time lines. You would travel back to last Saturday with the Lottery numbers in your hot little hand only to find different balls pop out as you head down a different time line from the one you came from

[dawkins]

Hi Jake

I didn't say it was impossible but that there is no evidence. There is no evidence that the past exists or that the future exists However what has been proved is the concept (phenomenon) of personal time (the twins paradox). Time travel has not been put to the world in a falsifiable theoretical framework

[mjhunt59]

To my understanding the only possible way of time travel is to fly into a Wormhole and as a result move faster than the speed of light and hope you come out the other side intact and would live long enough to travel back to Earth. Scientists have proved time dilation aka the twin paradox through measuring very small time differences over months/years of atomic clocks jet planes. so in theory at least going faster than the speed of light might slow time completely or even reverse it

[jake-the-peg]

well forwards time travell is well established. My favourite is the muons hitting the Earth from cosmic rays
http://www2.slac.stanford.edu/vvc/cosmicrays/c ratmos.html

(If anybody doesn't know all about this anyway).

The lack of evidence is interesting, after all you might think there was no evidence for radio wave 200 years ago - we didn't have the technology.

As many of these things revolve around extreme cases that's not too surprising.

So I don't think a lack of evidence should push us one way or another.

You could interpret the fact that relativity doesn't forbid it as evidence that it's possible but Gravity is very poorly understood in extreme circumstances so I don't think that helps us either.

Should we ever manage a theory of quantum Gravity and that too allows for backwards time travel It'd be much stronger evidence.

Of course Richard Feynmann famously pointed out that in some senses a positron can be seen as an electron moving backwards in time. That is generally seen as just a mathematical device rather than having any real foundation in the physical world. But if I wanted to invent a time telephone I think I'd be looking at anti-matter rather carefully

[Bazile]

Isn't the answer to the question ..... who knows
Who is to say what man's knowledge will be in a thousand years down the road ( if man and the planet are still here )