This topic uses some ideas of special relativity, so --since obviously not everyone in this forum is versed in SR-- if you don't understand some of my assumptions, apologies.  

First. We are using a theory posited by a man named Miguel Alcubierre called the Warp theory. It is a mathematical proof for the possibility of creating a warp bubble in Time-Space that basically collapses the fabric of space time in the direction of travel, and expands it in the opposite direction. Basically, folding up a sheet of fabric to make to end points much nearer together.  

The basic theory, sans most of the mathematics, can be found here:
PDF of Miguel Alcubierre's Warp Drive Theory
[note: This is NOT a viable means of travel at this point in time. The use of this idea requires "exotic" matter. Though, we are now better understanding what "exotic" matter is, and how it reacts with regular matter so lets keep our fingers crossed]

Ok, so based on this theory of space travel, one could travel at speeds that exceed 300,000 m/s [speed of light] without actually moving, thus upholding general relativity, and not requiring all of the energy in the universe to attain such a speed.

If we could do this, then we could travel to some where as, relatively, close as alphaCam in the Persius arm  Map of The Milky Way

then we might be able to return to earth in it's future.

The premise is this.  
Time is relative to speed. We know that. We have tested it and it is true [read: Atomic clock experiment]
But standing stationary is actually NOT stationary. Not only are we moving around as the earth spins, but we are traveling around the sun, as well as traveling around the Galactic nucleus in our star system.  

So. Let's look at the Milky way. It is a spiral galaxy, as far as we can tell, and we are on one of the more outer arms, though not the outermost. These arms spiral around the galactic nucleus at some speed, X. It stands to reason, then, that if we were to land our space ship on a planet in a star system in the outermost ring of the Galaxy, that we would be traveling faster than the Earth would, and thus, time would be slower.  

Of course, I would have to crunch the intensely complicated numbers to figure out how much of a time difference it would actually be, but imagine we could travel to a place in the galaxy where every year that passed by there, equated to 10,50, even 100 years on earth [it would likely not be that large, but a significant time difference could be seen].

So, then, if it takes only a short while to get to this other planet, and we set up a little space colony there, raise a couple kids, and come back to earth, we would have effectively [from our perspective] traveled into the future...

Ask away if you need clarification, and comment away about your thoughts on the matter, this is by no means a final copy, just some thoughts.

Post edited at 5:20 pm on July 25, 2008 by Event Horizon

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Life is pleasant. Death is peaceful.It's the transition
that's troublesome.   --Isaac Asimov

[ post scriptum: Screw verbosity]

Post edited at 5:34 pm on July 25, 2008 by Event Horizon

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Life is pleasant. Death is peaceful.It's the transition
that's troublesome.   --Isaac Asimov

Would not this sort of technology be comparable to the costs and energies required to say, accelerate a space ship at the speed of light?

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Genetics is fate. Change our genes, achieve free will.

The mention of "all of the energy in the universe" was referring to the amount of energy that would be needed to accelerate something to the speed of light.

No. it would NOT be comparable, since trying to make a ship go the speed of light would require, as I stated, all of the energy in the universe.

We may NEVER be able to travel between star systems, or even past mars, the technology might just NOT be possible without building planetary colonies and space "outposts" to "jump" from.
The space travel part isn't really my main concern with this though, it's really the implications of traveling to a system that is hurdling through space at a much faster speed than the Earth, and therefore is less effected by time.

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Life is pleasant. Death is peaceful.It's the transition
that's troublesome.   --Isaac Asimov

http://www.sciam.com/article.cfm?id=quantum-black-holes

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The problem lies in artificially creating such a light warp. A circulating light beam that twists and manipulates the fabric of time. However, this "time machine" isn't what we would normally define as time machine as.

It would only be able to allow travel from the moment it is activated. I compare it to a recorder. It would record all of time beginning from wence it is activated. And one would conceivably turn ON the Time Machine from Day 1, wait until Day 25, then go back to Day 1. This enables time travel from the FUTURE but it doesn't allow one to go any further than when the time machine was first turned on.

The implausibility lies within building the light prism. It would require vast amounts of light. And testing would also be difficult as well.

Does anyone have a good way of testing a functioning time machine to see if it was indeed working?

This is, I think, general scientific thought. Experimenting.

Post edited at 10:05 pm on July 29, 2008 by Takinam

If I built a ship and traveled at 99.99999999 percent of the speed of light, for 16 hours --my perspective time-- over 1000 years would have progressed on Earth [and a 27 year total trip would yield 6 million years of time difference. So if we, theoretically, built a ship that could --first off dampen the acceleration to a livable level so that we could reach that speed in some reasonable period-- travel at, say, a third of the speed of light, we could make month long journeys that would travel into the future.

If this were accomplished the only hard part --besides harnessing negative energy-- would be to create the wormhole that you would drag along with you into the future, so that you could set a starting point for the time travel.

As for the last question, it depends on the nature of what happens when you interfere with the past.
If time is like the space-loaf theory, and all events do not continue to happen, but merely exist. [based on the premise that from SOME perspective in the universe, if a universe-large camera were to take a picture, what we will call a now-picture, would see every event in time as happening NOW. Somewhere, from some perspective, the now-picture would be showing lincoln being shot, somewhere far distant from that we would see dinosaurs roaming the earth, somewhere else I might still be on the first word of this post.]
If that were the case, then regardless of what you do, it must be true that you did that in the past as well, even if you didn't know you did.

If the Universe's nature follows the many worlds idea, then you'd simply start a new branch of existence from your perspective, and the future according to you would change.

Though, back on topic, I was really only wondering about the possibility of super-fast craft allowing travel into the future.

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Life is pleasant. Death is peaceful.It's the transition
that's troublesome.   --Isaac Asimov

Travelling at light speed (excluding Alcubierre's or similar loopholes) is impossible, but not for the reason you might think.  The faster you travel, the more time dilates, and more your length along the path of motion is contracted.  This is called Lorentz contraction.  The faster you want to go, the more energy you need, and the amount of energy you need to go over light speed is infinite.  Literally.  

Second. we already travel into the future.  As far as we experience it, our travel through time is one-dimensional.  That is to say, we can travel in one direction, but not the other.  Straight line.  I think the effect you're attributing to "time travel" is actually "time dilation".  

Let's say you jump into the Enterprise, which has a new Alcubierre warp drive.  You fly off to the end of the galaxy, as I watch you in my super-telescope that can see your ship, no matter how far away you go.  From my point of view, several things happen as you fly at light-speed (or even near light-speed, for that matter): the ship's colors appear to be changing, moving from the bluer end of the spectrum to the red end.  Some of the red paint on the ship may even disappear, as they slide off the visible light part and into the infrared part.   This is called Doppler shift.

Also, most importantly, you and your ship will appear to be moving slower and slower as you accelerate.  This is time dilation.

From your point of view, the same will be happening to me.  Time runs normally for you, and the colors in your ship are the same.  

However, when you return, we compare what time our clocks say it is.  Because you accelerated, and I was still, your clock will have ran slower than mine.  I will say you've been gone, for say, 30 years, when you might say you've been gone for 3 months.  The specifics depend on how fast you were going, how far you went, and so on, but you get the idea.

Hope this clears it up for you.

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Some nits I feel an urge to pick.  

Travelling at light speed (excluding Alcubierre's or similar loopholes) is impossible, but not for the reason you might think.  The faster you travel, the more time dilates, and more your length along the path of motion is contracted.  This is called Lorentz contraction.  The faster you want to go, the more energy you need, and the amount of energy you need to go over light speed is infinite.  Literally.

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I'm not sure you are grasping the concept, however.

First of:
1. Alcubierre warp drive is a model for FTL speed utilizing distortions in space time. The craft used to traverse the distance does not move at all within it's warp bubble, it is, in theory, completely agreeable with special relativity. Once the warp bubble is created [and there have been supplemental models that have lowered the amount of negative energy needed to levels that are --theoretically-- attainable.  

2. I will post later a more developed idea, one which utilizes speeds approaching light speed, lets continue.  

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Second. we already travel into the future.  As far as we experience it, our travel through time is one-dimensional.  That is to say, we can travel in one direction, but not the other.  Straight line.  I think the effect you're attributing to "time travel" is actually "time dilation".  

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The effect I am explaining is time travel as a RESULT of time dilation.  
If you travel at a faster speed for time, X, and the earth travels around at its typical speed through the universe,  then there will be a difference in the amount of time experienced.  

If I travel for 10 years going a third of the speed of light, I will have experienced ten years, and the earth will likely have gone through perhaps 100. [I am working on the theoretical math and it seems that at 99.9999% --unattainable-- of the speed of light, if you travel 27 years round trip, the earth will have progressed 6 million years.  

THIS is what I am talking about, and if that is not time travel, then I don't know what is.

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Let's say you jump into the Enterprise, which has a new Alcubierre warp drive.  You fly off to the end of the galaxy, as I watch you in my super-telescope that can see your ship, no matter how far away you go.  From my point of view, several things happen as you fly at light-speed (or even near light-speed, for that matter): the ship's colors appear to be changing, moving from the bluer end of the spectrum to the red end.  Some of the red paint on the ship may even disappear, as they slide off the visible light part and into the infrared part.   This is called Doppler shift.

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I'm going to assume that this "explanation" was given to help develop a point? lol I'm studying Aerospace engineering, with a focus on vacuum propulsion. I'm also beginning a degree in Astrophysical theory, believe me, I know the material. [Note: I do not post this information to brag or to patronize, I'm merely mentioning that I am versed in the subject, and that if you are as well, we can skip the Chapter 1 stuff... Though, I appreciate your response, and understand where you are coming from, I too use elementary explanations in some of my posts when working towards bigger points; moving on    

Again, the process by which you would be moving is not one of propulsion. It is a "bubble" in space:

That, by its nature, distorts the fabric of the cosmos, basically changing the distance between the points.  

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Also, most importantly, you and your ship will appear to be moving slower and slower as you accelerate.  This is time dilation.

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agreed, but irrelevant in this discussion...  

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From your point of view, the same will be happening to me.  Time runs normally for you, and the colors in your ship are the same.

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Yes, if I looked in my super-telescope aboard my ship, you would appear to be looking at me. However because of the dilation of time, I would in fact be looking at you how you were in the past [several seconds, hours, days, or even years depending on how fast I'm moving away and how long I've been holding speed.    

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However, when you return, we compare what time our clocks say it is.  Because you accelerated, and I was still, your clock will have ran slower than mine.  I will say you've been gone, for say, 30 years, when you might say you've been gone for 3 months.  The specifics depend on how fast you were going, how far you went, and so on, but you get the idea.

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You realize that that is pretty much the exact point that I'm making, right?

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Hope this clears it up for you.

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Post edited at 7:55 pm on Aug. 24, 2008 by Event Horizon

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Life is pleasant. Death is peaceful.It's the transition
that's troublesome.   --Isaac Asimov

Anyway, I concede your point that it's time travel into the future.  Pretty pedantic of me, now that I look back on it.

Anyway, the Alcuiberre warp (assuming it works, of course) is pretty interesting.  It pops up from time to time here, and I admit I didn't quite think about what I was saying about FTL before I said it.  

Of course, the question remains: where you gonna get that much negative energy?  Squeezed laser states are too volatile and unreliable, and Cashimir plates would require huge amounts of precisely aligned materials...

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Okay, I apologize for the Chapter 1 stuff.  It's just that I've found that when this kind of stuff comes up on Livewire, it's best to start there, simply because more often that, the person is talking about something they don't fully get.  Majority of idiots, and all that.  I apologize if I offended you.

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Again. None taken, I do the same myself.

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Anyway, I concede your point that it's time travel into the future.  Pretty pedantic of me, now that I look back on it.  

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Ah, good. I mean not like it really matters, it is all theoretical and what not, but I'm glad when agreements are come-to.

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 Anyway, the Alcuiberre warp (assuming it works, of course) is pretty interesting.  It pops up from time to time here, and I admit I didn't quite think about what I was saying about FTL before I said it.

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Last time I saw it was when I posted it as Norock, way back when. It is a common misconception when talking about FTL speeds. Often people hear the word faster and associate it with velocity...  

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Of course, the question remains: where you gonna get that much negative energy?

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Squeezed laser states are too volatile and unreliable, and Cashimir plates would require huge amounts of precisely aligned materials...

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Yea, I don't see anything of the sort coming into action any time soon. I focus mostly on the Biefeld-Brown effect and its possible applications in a vacuum.

Post edited at 10:30 pm on Aug. 25, 2008 by Event Horizon

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Life is pleasant. Death is peaceful.It's the transition
that's troublesome.   --Isaac Asimov