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Will Time Travel Ever Be Possible?

7 Answers
I'm not talking about neutrons slightly shifting in phase or some undetectable movement of light, I'm talking about people literally being able to move in time like in the movies. Personally, and based on the limited science I understand, I don't think time travel backwards can ever be possible, especially with all the paradoxes involved. Time travel forwards, in perhaps a small step at least, may be at least feasible to a more advanced world in the future. Of course we're all moving forward in time anyway, just not very quickly.
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Well, If mankind can outlive it's own self-destructive tendencies long enough, I don't believe that such a feat would be impossible. It may be in part due to my own personal optimistic outlook, and reading of the predictions of some of the greatest minds in the past that have been made to look all but childish today. Like a quote I remember word for word, for this very reason, by the great scientist Lord Kelvin, who once proclaimed, "Radios have no future, 'heavier than air' flying machines are impossible, and x-rays are a pure hoax!" When the source is considered, this goes to show, just how little even the brightest amongst us may, and likely do know about our own "world" at a given point in time.

But to get back to the specific question, there is by no means a known law that strictly prevents such a invention from being possible. There are paradoxes which seem to defy logic as we currently understand it, although strictly speaking a paradox is not something that IS impossible, rather a trickery, or something that appears to be impossible, as far I know there is but one paradox which has not been "solved", but is will surely be figured out one day unless it is a truth and not a paradox in which case something else we believe in has failed and it is the "proof" of this other concepts failure.

The theories of relativity predicted by Albert Einstein, tell us that the very universe we are born into appears to be filled with "things" that are all moving at different speeds relative to one another, depending on factors like their mass, and speed. Were living "out-of-sync" with the very stars and planets, and to a much, much lesser extent - people (often considered negligible in effect, but still can't be said to be absent), for which we were "in-sync" at the moment we were "born", or originated! If examined using this point of view, it can offer some reassurances that such technologies could exist.

The is another theory, that has been proven, and held up to scientific scrutiny for many years, which I believe would help explain any paradoxes you may find on time travel. It was developed by the US Physicist Mark Everett, III, who sadly never lived to see it's wide-spread acceptance, and accepted proof by quantum physicists. This theory is commonly called the Many Worlds theory, although It is better described as a theory of "infinite universes". It states that at each moment of time that a decision is possible, there is a splitting of sorts, "creating" a new universe for each possible outcome, much like time might be though of to create a new universe at each moment - since any two moments in time are clearly not "the same". The Many Worlds theory is considered an uncertainty principle in quantum physics. It basically places the universe itself as another dimension, and I'm not speaking as in the science fiction concept of the term, but more like a time-space dimension. So if each "child" of a single "parent" universe is identical in all aspects up until the point of deviation, that moment of that single choice, then all outcomes exist. (Possibly already! And we merely choose which way to go at the "forks in the road!")

Whether all possible outcomes do already exist or are created is somewhat trivial though, but the shining light at the end of the tunnel is that time-travel suddenly becomes a real possibility! See, in the popular paradox of Shrodenger's cat a solution is easily found, because the cat is BOTH alive and dead simultaneously resulting from the two outcomes existing in two distinctly different universes, instead of the general expectation that the cat is NEITHER alive or dead!

If you were to go back in time an take the life of yourself as a child, the splitting point where you decide not to pull the trigger exists just as real, and this is not the same set of choices that has lead to your current life as you are experiencing it anyway, so you are not breaking any logical progression of events across a single timeline at all!

The real difficulty in developing a "full-sized" human time machine, is how to actually move between such places, assuming it is even possible (which I will point out again, NOTHING states that this is not possible from our current laws and principals in science.) Just like wormholes in space, that could allow moving any distance at a much faster than conventional means between any two points in the universe, but it has the similar difficulty of a lack of a real known means of how to initiate the implementation of such an event.

I think that we could solve such "riddles" given enough time, be it century's or millennia! Although this leads me back in a circle to the beginning of my answer: How much time do we have to work on such things, if we can not keep from sterilizing the universe of or own race, ironically, the "Human Race".

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Lynden95 - I would say that it is highly unlikely that anyone could come back in time to the same "linear time-line" like you might imagine it, instead think of it as a separate time-line(s), like I mentioned above, altering such a time would have no effect on you or your time, because it does not have the same origin before the point you would return to. That is why we have never had visitors from our future, and never will. Only in the outcomes that never actually took place from our frame of reference (which we will never be aware of. You don't need any physics background, just an open mind and the willingness to ponder ideas you are unfamiliar with. Maybe you will even find that you are a theoretical physicist! And speeding up to the speed of light is not necessary to alter time (as Special Relativity compared to General Relativity can show us. As one becomes asymptotic toward the speed of light the same phenomena occur just not to the ideal extreme cases.
Anadio95 - I agree, although seeing something that isn't currently in existence doesn't mean it exists as such, you see your reflection in the mirror, yet there is only one you. The big bang can be seen at present from certain vantage-points, yet it is most certainly over, you and I can assure anyone of this!


Using General Relativity alone it is possible to speed up anything at near light speeds and make them "move into the future" ....so disregarding the difficulty involved, why wouldn't moving everything in the entire universe at a fast speed not cause all but yourself to move into the future, therefore placing you in the past of the entire universe. While it may sound impossible it shows proof of concept. And remember how ludicrous the world once sounded as a sphere, rather than having edges that spilled over into ......hmmmm ...what?

;)

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A

Its already happening on an atomic level, when electrons travel at speed of light and faster. Unless matter with mass becomes mass less, then maybe it can travel at speed of light and even faster, enabling it to travel in time but this is still not feasible. Any thing with mass trying to reach speed of light causes its inertial mass to double, which then makes it impossible for it to reach this speed. I always imagine traveling to the past is possible in the future yet we can only see things and events without being able to manipulate it. Consider this scenario, there was an inhabited planet somewhere in space that used to exist much before. This planet revolved around a star that used to exist but imploded long time ago. The light emitted from this star and reflected from this planet and the cities in this planet reached to Earth after hundreds of light years later from the time this planet ceased to exist. Consider we analyzed the light reaching Earth with advanced technology and saw images of those cities on the once existing planet. This to me, proves that we can see the past but we cannot manipulate it maybe unless we can travel faster than light in the opposite direction from its source.

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Entropy is based on matter tending toward CHAOS from a more ORDERED state along with the FORWARD movement/passage of time, so by definition - if it were possible to move backward linearly on a simple time-line, completely disregarding all I have mentioned previously, ORDER would tend to follow CHAOS. Don't expect time-travel to seem logical according to your current standards of conceptualizing the universe and time.

(You are not violating any rules, if and only if (iff), time is moving in REVERSE. All event's happen in the opposite order because of the frame of reference you are observing them from, not because they are TRULY becoming more ordered as some seemingly real time-line is oriented in the opposite direction. Time is perceived. And for some reason it is perceived directionally like a vector. we could experience space-time in a different manner, reactions would appear to be caused by actions.)

"You cannot depend on your eyes when your imagination is out of focus." - <Mark Twain>

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I would say it will never be possible to move backwards in time, I think one day it may be possible to move forwards.

My reasoning is the Universe tends toward entropy. If you don't know already, this means the universe is going from an ordered state to a less ordered one, and this is the phenomoena we kow as the advancement of time.

Going backwards in time would reset entropy, thereby making the universe unstable. Einstein's Theory of Special Relativity renders this impossible. Entropy must always move forwards and never backwards. It would be like expecting a pile of sand to turn into a sandcastle in the wind, rather than the other way round.

Forwards in time however, would be a simple case of speeding up entropy relative to your position. How this would be done remains to be seen, but it is certainly theoretically possible.

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L

I am not a scientist or inclined to know or understand very much regarding physics but if time travel was ever possible why has there been no evidence of people from the future being among us now? If this was Hollywood they would be able fit seamlessly into our society but in reality they would have messed up at some point and made their presence known.

Unless of course, the multitude of UFO sightings aren't in fact beings from another planet but rather our own offspring visiting the past!

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S

Yes, I think time travel will be possible. If a person travels at a high rate of speed for a while they can travel into the future. However it may never be practical. I do not think you would be able to get very far into the future. A better solution would be to slow down your aging process so you live longer or use suspended animation.

The problem with going into the future is that you would not be able to go back. If you want to see the future take care of yourself so you live longer.

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