Why time travel must be impossible!

So I suppose travelling at or above the speed of light would enable you to travel forward in time but only by slowing down your own time (perceived time), It would be impossible to return to the time you started at.

Time travel to the future is completely possible! within our lifetime i think we will have the capability to freeze a living human and then that human could be awakened 100's maybe 1000's of years in the future. IMO it will never be possible to travel back in time though!

reply to post by Pilgrum

Also, you have to think about the position of the Earth in space. If you were to "start" going back in time during the winter and ended up in the past during the summer, you would end up in space and not on Earth, since the Earth would be on the opposite side of the solar system. This is my theory if you were to look at the universe as a 3 dimensional space and your position as x, y, and z coordinates.

Furthermore, if this scenario happened, you probably wouldn't be in this solar system because the solar system moves as well. For example, if you wanted to see the dinosaurs 65 million years ago, you would probably be in another galaxy and not on Earth. You would have to come up with the right time for the Earth's position to be where you exactly left off. But this would be impossible due to the solar system's movement through our galaxy.

Sorry to break it to you guys, but we already have seen how time travel is possible. As seen being done by Superman, it involves flying many, many times around the earth at very high speeds until time is reversed. I'm sure this method could be done in the opposite direction in order to make time speed up.

Seriously though, based on the example given with the two aircraft with clocks on each one, I think that it warrants pointing out a clear difference between two time travel related concepts. While the two planes example is time travel on a very minute scale, it fits the definition of traveling "through" time faster than something at your point of origin. Unfortunately it only goes to show that that method would only work for making time pass more quickly, rather than "jumping" from one time to another. And I think that that is a major point that needs to be made.

Time TRAVEL, at least in the context of what I am writing here, is something we do every day as we go about our lives. It's the product of physics. Just because you hop on a spacecraft and take a 50 light year journey does not mean you're actually traveling through time, does it? You'd just be witnessing the laws of physics as they pass normally and without influence of some technology (unless you consider the spacecraft an influence, but it's not actually manipulating the rate at which time passes, it's just traveling really fast).

Time JUMPING (not sure what else to call it) is what I see as time travel. This would be the ability to move from one point in time to another point in time while "skipping" over some length of time that would have occurred between the point of origin and the destination.

It's this jumping that I am extremely skeptical will ever be possible. I mean, how would you specify your destination in all four dimensions being traversed?

To be honest, I hope time jumping is never achieved by mankind. The idea that the past could be secretly manipulated is something I never want to worry about.

Okay, so motion is Relative.
If you travel at 99% of the speed of light, then 1 year for you might be equivalent to 100 on the "stationary" Earth.

But.... motion is relative.
So the above journey could be viewed as YOU standing still, while the Earth zooms away at 99% of the speed of light. So the Earth would age 1 year to YOUR 100.

I must be missing something here.

as far as the time/motion being relative thing... let's do a little experiment.

look around you. everything still? nothing moving? aside from the kids, or the cats, or what have you? nothing flying across the room? or off into the atmosphere?

so you'd say everything around you is still, and unmoving, right?

you're right from your own frame of reference, but from a truly 'objective' frame of reference, we're all rocketing through space at an insane speed while spinning ludicrously, not unlike a top. we're still beings on a spinning planet, which is further spinning around a sun, which is also spinning around the middle of our galaxy, which is, itself, drifting through space. so, really, it IS all relative. you look at your computer, and to you, it's not moving, but to a truly objective observer, it's moving incredibly fast. all relative.

now, as for time... there are different ways you can view it, really, and which view you work with depends on how you should view time travel.

the fad right now is to see time as a fourth dimension, the same as our 3 physical ones. if that's the case, scientists hypothesize that eventually, since we're clearly moving in the dimension of time anyway, it's only a matter of time(heh) until we learn to control that movement. one good (but rudimentary) visual diagram I saw explaining how time travel might be accomplished under this model is, in the same way that a piece of paper (time) can be folded in half, and a pin pushed through so that, relative to the flat sheet (regular flow of time) the pin occupies two points 'at once', so might someone who can move freely through time pop in at two separate points in time 'at the same time' (in their perception). this is all rather sketchy, in my opinion.

another way to look at things is that time has to do with kinetic energy. as mentioned above, we're all moving at incredible speeds, and since relative changes in speed seem to affect local time, this has some merit. this would mean that as opposed to being a fundamental quality of our universe, time is simply a byproduct, function, or side effect of movement, momentum, kinetic energy, or what have you. this intrigues me mostly because I haven't heard it discussed as much as the 'time is the fourth dimension' theory.

i'm sure there are other models and theories (both amateur and professional) out there, but these are the two that spring to mind for me, personally.

you also need to consider the implication of quantum mechanics when discussing time travel in a serious manner, though. there's been hefty evidence that time is meaningless when you consider things on a quantum scale, as is space, which leads to some pretty interesting theories about time-space in the quantum arena.

Einstein lowered the Human I.Q. by about 50 points, he also stole your ability to think freely and rationalize concepts that are otherwise fairly simple ordeals.

Originally posted by LastOutfiniteVoiceEternal
Einstein lowered the Human I.Q. by about 50 points, he also stole your ability to think freely and rationalize concepts that are otherwise fairly simple ordeals.

So why do you say that?
I think he made the universe a rather more interesting, less obvious, place.
He showed that the world might not unnecessarily work according to the simple Newtonian laws we observe from our very limited point of view.

And, for what it's worth, Relalativity been tested and show to be correct.