[Renate]

Ok, so I havent really learnt anything about time travel, but to those who might know a bit about this I have a question: what about time travel to the future? That shouldnt be a problem, if we can go back in time, right? Or am I missing something here?

[molle]

Not backward, not forward.
I find it unlikeley that we will ever have the technology to travel in time, and if we ever get the technology, I believe it will not be used, for fear of what som time pilot might do to mess with history.

[Wagenius]

<< Not backward, not forward.
I find it unlikeley that we will ever have the technology to travel in time, and if we ever get the technology, I believe it will not be used, for fear of what som time pilot might do to mess with history. >>



Hmm .. Im not sure i agree here. Once there was a writer who told a story about a boat that traveled 20000 leagues under the sea. He also told as story about how two men traveld to the moon and back. What Jules Verne wrote in his days was commonly thought of as science fiction and completely impossible. Today we have thousands of submarines, and not only traveled to the moon, but also walked on it ... many times.

The future will take a long time to explore and what we technologically will be able to do MIGHT also include Time Travel. I think it is a possibility, regardless of our current status on the matter =)

As for "messing with history".... if you travel to 1960 and buy an icecream, then you already have done so =) ... Its a matter for the philosophers. Can one change history with time travel or not? Perhaps ... never heard any arguments that rules out either possibility

[frog]

Or are we 'locked' in our own time, only to escape when we die = go out of time. Another interesting thought: would it be possible to enter 'another time' - in a different dimension? And will we be able to return to our 'own time'?

[Wagenius]

As we seem to be in the philosophical corner here ... Recently saw the movie K-Pax ... which had its own view of this. "On K-pax we know that the universe will eventually collapse upon itself. It will then explode again and everything will be repeated exactly as it happened the time before. So get it right the first time, for you will be repeating both the good and the bad times an infinite number of times" (quoting from memory here .. so I may be off on a word or two =) ). Wierd way to envision how the universe works, but an intriguing idea after all =)

As everything has happened has happened .... will it be possible to alter it after the event has already occured. "Can you be your own grandfather?".

Ill not even START to think about that one =)

[Tormod]

You should check out the hypography on time travel and also the one on The Arrow of Time, which discuss the matter further.

[Tormod]

The K-Pax idea that the Universe is constantly blowing up and contracting is not generally accepted by cosmologists today, although it has been one of the many interesting theories.

In the book "The Five Ages of the Universe" (Hypography review) the authors argue that the universe will last for so long that all the matter in it will be exhausted before the cosmos eventually disappears.

However, some interesting ideas arise within something called "anthropic" theory, which claims that the Universe we live in is the way it is because we are here to observe it. This might lead to an obvious question: perhaps our universe is indeed one universe in a long sequence of universes, and only one of a multitude of parallell universes, born out of each other...much like evolution, in fact. Perhaps universes evolve and improve as well?

But my point is basically that if in fact our universe should collapse and regenerate, it would not be the same universe - I think this is an important point.

As to how this applies to time travel I don't know...just my 2 cents.

[Tormod]

wagenius -

Stephen Hawking has a neat resolution to the problem of "if time travel is possible, why haven't we been visited by travellers from the future?".

His argument is that if you are able to create a time machine, it will never be able to travel further back in time than to the date on which it was created. He sees this as some sort of built-in cosmic defence mechanism to avoid the paradoxes which arise from time travel.

However, it does not resolve the grandfather paradox. To do this, he says there is a possibility that when you travel back in time, you actually enter a universe which is very similar to ours, but not exactly the same - at the moment you arrive in time, the universe splits into two in some quantum fashion and from there the two variants branch off in different paths. So if you accidentally kill your grandfather before your father is born, you only kill him in this "new" universe, not your old one. So you still exist, even though you have killed your grandfather - because there are (well, were) two of him and you can never get back to the original one. As for your identical twin in the parallell universe, well, tough luck.

[Yvonne]

I have a question - do we live in the parallell universe or does my twin? Am my twin supposed to to excactly the same things as I am? If not, it wouldn't be parallell, and if - if my twin is killed it can no longer be parallell??? I find it too confusing to be belivable - no there can't be parallell universe.

[Tormod]

Well, in my exampleyour twin does not exist until you go back in time, at which point the entire universe splits in two and goes in different directions (albeit very similar). Your twin would of course NOT exist if you kill her grandfather before her father is born...

But the idea of a multitude of universes is not merely gobbledygook, it has received serious attention from many scientists. There is something called"many worlds" theory which argues that at every moment a decision has to be made on a quantum level (say, should this electron bounce this way or that), the universe actually splits and each copy takes the opposite direction, so that both things actually happen.

I didn't say it's credible, though.