Naked Science Forum
Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: Craig MacMurray on 07/07/2011 21:30:02
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Craig MacMurray asked the Naked Scientists:
Dear Chris,
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This email might make me sound a small bit insane but I do not care. I have been reading about Einstein recently and it seems to me that he is saying in his workings is that time travel is possible. And I have always wanted to take his work further to make him proud so if you know anything on this subject please do tell me.
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Kind regards
Robert MacMurray
What do you think?
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No, I don't think he did personally. I don't either :)
To assume that you could would either imply that you not only set back the clock for you, but for all of infinity, or maybe 'just you'. In the first case, where did that 'energy' come from, was it infinite too? His equations, as they treat 'time' as a 'dimension' amongst others, where all of them join into SpaceTime that somehow becomes like a jello, reacting as a 'whole' when you 'push' one parameter can be 'tweaked' to allow it, but not of his origin. There are all kind of tweaks to those equations, people have been manipulating them for over a hundred years now, to see what they can get out of it.
"In 1949, when his good friend Kurt Gödel showed that a rotating universe allowed for time travel, he was deeply worried.
Gödel, in fact, would pester astronomers visiting Princeton and ask if there was any sign that the universe was rotating. In Einstein’s writings, he finally concluded that time travel might be inherent in his equations, but they can be dismissed "on physical grounds," i.e., they could not form using known physical mechanisms. In other words, the universe expanded, not rotated. So if the universe did rotate, then time travel might be an everyday occurrence. This argument holds even today. There are a large class of solutions of Einstein’s equations, but many can be dismissed "on physical grounds." For example, in 1937, W.J. Van Stockum showed that a spinning cylinder that was infinitely long could satisfy all of Einstein’s equations. Decades later, it was shown that the Stockum solution actually allowed for time travel. If you danced around this cosmic Maypole fast enough, you could come back before you left. But again, "on physical grounds," one can argue that cylinders can never be infinitely long, so this was just a mathematical curiosity." Then you have Black Holes, 'stabilized' worm holes clad with 'exotic (negative) matter' etc.
So the math seems to allow it but I don't think it will work in reality. If you really could go back you either would end up 'somewhere else' or in your own 'time line'. If you did you would now have introduced something not existing there in your own history of it, creating a closed 'time loop'. There are all kinds of reasons for it not working, although such have never stopped the visionaries. But we're testing it with light, and maybe it will 'work'? For light that is, doesn't state that it will work for matter though. And, as far as I know no one has succeeded yet. Also, if there was that possibility we should already see it, as we would be someone else's 'history'.
Time travel Physics. (http://plato.stanford.edu/entries/time-travel-phys/)
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No, I don't think he did personally. I don't either :)
To assume that you could would either imply that you not only set back the clock for you, but for all of infinity, or maybe 'just you'. In the first case, where did that 'energy' come from, was it infinite too? His equations, as they treat 'time' as a 'dimension' amongst others, where all of them join into SpaceTime that somehow becomes like a jello, reacting as a 'whole' when you 'push' one parameter can be 'tweaked' to allow it, but not of his origin. There are all kind of tweaks to those equations, people have been manipulating them for over a hundred years now, to see what they can get out of it.
"In 1949, when his good friend Kurt Gödel showed that a rotating universe allowed for time travel, he was deeply worried.
Gödel, in fact, would pester astronomers visiting Princeton and ask if there was any sign that the universe was rotating. In Einstein’s writings, he finally concluded that time travel might be inherent in his equations, but they can be dismissed "on physical grounds," i.e., they could not form using known physical mechanisms. In other words, the universe expanded, not rotated. So if the universe did rotate, then time travel might be an everyday occurrence. This argument holds even today. There are a large class of solutions of Einstein’s equations, but many can be dismissed "on physical grounds." For example, in 1937, W.J. Van Stockum showed that a spinning cylinder that was infinitely long could satisfy all of Einstein’s equations. Decades later, it was shown that the Stockum solution actually allowed for time travel. If you danced around this cosmic Maypole fast enough, you could come back before you left. But again, "on physical grounds," one can argue that cylinders can never be infinitely long, so this was just a mathematical curiosity." Then you have Black Holes, 'stabilized' worm holes clad with 'exotic (negative) matter' etc.
So the math seems to allow it but I don't think it will work in reality. If you really could go back you either would end up 'somewhere else' or in your own 'time line'. If you did you would now have introduced something not existing there in your own history of it, creating a closed 'time loop'. There are all kinds of reasons for it not working, although such have never stopped the visionaries. But we're testing it with light, and maybe it will 'work'? For light that is, doesn't state that it will work for matter though. And, as far as I know no one has succeeded yet. Also, if there was that possibility we should already see it, as we would be someone else's 'history'.
Time travel Physics. (http://plato.stanford.edu/entries/time-travel-phys/)
Check the newest thread here on spinning universes. It seems a universe can expand and spin at the same time.