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PhysicsILike
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Theres the Butterfly effect and Grandfather paradox which makes logical time travel into the past difficult. Is there any theory or anything which suggests it may be possible?
Ivan Seeking said:By the butterfly effect I assume that you mean the multiplicative effects of changing history. This was misinterpreted the first time which is why the thread was deleted.
I think it is fair to say that while the door hasn't been closed entirely on travel to the past, it may be that the energy requirements would far exceed anything possible for the foreseeable future - maybe beyond anything that will ever be possible. There is also the [physics based] argument that one could only travel back to the point in time that the time machine is first turned on.
The Future of Spacetime [2002] has a nice series of essays on this subject.
Ivan Seeking said:By the butterfly effect I assume that you mean the multiplicative effects of changing history. This was misinterpreted the first time which is why the thread was deleted.
I think it is fair to say that while the door hasn't been closed entirely on travel to the past, it may be that the energy requirements would far exceed anything possible for the foreseeable future - maybe beyond anything that will ever be possible. There is also the [physics based] argument that one could only travel back to the point in time that the time machine is first turned on.
The Future of Spacetime [2002] has a nice series of essays on this subject.
Ivan Seeking said:I think it is fair to say that while the door hasn't been closed entirely on travel to the past,...
The Future of Spacetime [2002] has a nice series of essays on this subject.
Raap said:Travelling to the past is simple; just move all particles back to the way they were at the time you want to be.
skeptic2 said:It seems that the conception of most of us have about traveling back in time is similar to the movie Back to the Future in which a person from the present travels back to the past but remaining as he is in the present. This view presumes that somehow the time traveler continues to travel forward in time while the rest of the universe has traveled backwards.
If travel back in time were possible it would mean rewinding the whole universe to that time. The Earth would have to orbit backwards and even air molecules would have to retrace their exact paths from the present to the past. All aging and knowledge gained would also have to be reversed. Anybody arriving in the past from the present would do so naively without any of the knowledge time from which he came.
The whole point of returning to the past of course, is doing so with the knowledge of the present. However this seems to always involve the potential for paradoxes or absurdities - great for movies but very problematic in practice.
Nick89 said:Exactly the way I have always thought of time travel. Maybe we are all time traveling now and then, we just don't know it because our memories of 'the future' don't exist in 'the past'.
...and he's right, of course - it's simpleLambda3 said:Your proposition is correct if one only wants to travel to an instantaneous moment in the past. After that moment, though, the particles wouldn't necessarily behave in the same way as they did in the past.
Alfi said:One of the better ( imo only ) sci-fi films with time travel as the theme I've seen is 'Primer' (2004)
The acting/screenplay/dialog is not the best but I enjoyed their treatment of the paradoxes involved.
Wellgmax137 said:I think it was Steven Hawking who asked, if time travel is possible, "where are all the tourists from the future?"
It depends on the physical meaning of the PAST. Does it exist for eternity, 'somewhen'? Or are spatial configurations transitory? General relativity allows backward time travel in principle. But that doesn't necessarily mean that the dynamics of the physical universe allow it. Is the universe really evolving, ie., continually changing, or is it a static laminate of spacetime slices that we worm our way around in?PhysicsILike said:Theres the Butterfly effect and Grandfather paradox which makes logical time travel into the past difficult. Is there any theory or anything which suggests it may be possible?
Alfi said:One of the better ( imo only ) sci-fi films with time travel as the theme I've seen is 'Primer' (2004)
The acting/screenplay/dialog is not the best but I enjoyed their treatment of the paradoxes involved.
BoundByAxioms said:It's funny you mentioned that movie: the moment I saw this thread I immediately signed on to it so I could recommend that people watch it. I liked that movie, even though it was extremely confusing.
Alfi said:It sort of makes more sense if you go back in time and watch it again.
:rofl:
PhysicsILike said:I have just come back to the future and watched it and I get it now. (Of course I hid my self in a room for 3hours so when I go back in time I don't bump into myself. I also used a particle machine to create a bubble around me making sure I don't affect anything, even the atmosphere was not disturbed. I then used an invisible cloak stood behind my self the first time I watched it so I could watch it again.) - This would create no paradox.
lol - no sure eh? :rofl:Kronos said:correct?
naikaj said:ok i got wat u said but then why does the grandfather paradox still exist?? like if i were to go into the past and kill my grandfather then wat difference would it actually make.. i just woudnt vanish into thin air.. i already exist