Do you think time travel will ever be possible?

[FreemanHL2]

I have this theory that if you could travel out in space far enough so that you are receiving light from the earth that is 100 years old, then get a telescope powerfull enough to see the surface of the earth from that distance, you could actually see the events of that time unfolding... it is by all means possible, and infact we are all witnessing the earlier events of thousands of stars right now when we look at the sky.

 

[AluminumStudios]

Originally posted by: cquark
General Relativity permits time travel, and you can find scientific papers explaining how to do it in detail.

If I recall (I may be wrong because I've just recently been reading about this), Special Relativity says that we are moving forward in time at the speed of light. If we move though any of our 3 spacial dimensions it takes speed away from trip through time (much like a person takes longer to walk diagonally across a long rectangular field than straight across because your speed it split among 2 axis or dimensions) - and hence the reason if you travel near the speed of light you age more slowly.

That would imply that you must go the speed of light to stop time for yourself, then exceed it to go back in time (assuming that plugging speeds greater than the speed of light into the known equations that give you the "time dialation" at various speeds yields sensical answers.

If time travel into the past is possible (and I absolutely don't think it is) it's discovery will come along with another one - exceeding the speed of light.

It's not very easy to break universal constants. The only thing that might have ever broken the speed of light was the period of inflation of our space in the microseconds following the Big Bang ... and there was a heck of a lot more energy available then than there is to us now!

So my answer to the question that started this thread is no.

 

[kotss]

Originally posted by: FreemanHL2
I have this theory that if you could travel out in space far enough so that you are receiving light from the earth that is 100 years old, then get a telescope powerfull enough to see the surface of the earth from that distance, you could actually see the events of that time unfolding... it is by all means possible, and infact we are all witnessing the earlier events of thousands of stars right now when we look at the sky.

But how do you propose to get into space that far and outrace the light that has already
left earth. Do you plan to go faster than the speed of light. Otherwise you will be seeing
light that has left earth after you did.

 

[f95toli]

The thing is : GENERAL relativiyy beats SPECIAL relativity every time.

SR does not include gravity and therefore and it is not possible to "fold" spacetime.
In GR you can "fold" spacetime, make holes(wormholes) etc and that is what opens up the possibility for time travel.
You no NOT need to exceed the speed of light in order to travel in time in GR.

 

[GRIdpOOL]

We have applied this principal. Once you use predictible distances, you can control the attitudinal. I don't want to get into the specifics here, but I can asure you that time travel has been accomplished within deployable spacetime.

 

[GRIdpOOL]

This is the most important fundamental in "time" travel. There is no speed necessary to accomplish any degree of movement. The addition of G to a field of space inherently possesses a "dent", if you will, and constitutes benign progression regardless of direction. Once again, we don't need to get into specifics, but you shouldn't have any doubts.

 

[FreemanHL2]

Time is very interesting, it plagues all of us! I do believe that time is infact different from different perspectives, for instance an insect actually sees things slower than us.

So time is both a perception and a reality. Time as we percieve it is just the unfolding of events, but physicaly those events are unfolding at a universal constant. So OUR constant and the universal constant are different.

Because we can see events before our time (i.e the stars), and time actually slows down in relation to the speed of light, it seems that light speed remains a key figure in space time theories. HOWEVER, there is nothing to prove that moving at a near light speed and slowing down time doesn't mean that time will not keep slowing after you surpass light speed. In other words, who says that it is in relation to light???

It could be a far simpler explanation... although I doubt simplicity is what we are trying to achieve . Greater speed = slower time. Is it not true that a ball will roll faster the closer it gets to a descending cone? Would it not prove logical that an object heading towords a wormhole continues to orbit closer to its centre at a faster rate and if it reaches the centre it should be sucked into the wormhole at an infinite speed, and therefore distorting time as we know it? Perhaps that is why light does not exist in a wormhole, because everything inside is travelling at infinite velocity and therefore time does not exist and nothing is visible.

This would therefore indicate that time can differ on a per-particle basis (each particle can travel at a differing speed). If an atom is travelling at a fast velocity then time slows down for the atom and everything around it appears to be moving faster... the difference is we have brains and time remains a constant element for us. Therefore when we travel at near light speeds our brain tells us that 5 sec have passed, but 5 min has physicly passed.

If light speed did = The speed of time. Then light would logically cease to ever appear because it would therefore be travelling backwords, or seace to exist because it would always keep par with time and would therefore fail to reach us. Light must then be travelling at a constant speed through time, and therefore "takes TIME to reach us."

It would also appear that gravity is important in relation to time, because it effects the speed at wich something travels. Perhaps a wormhole is a "tear" in gravity??? The closer you get the more gravity is applied, but that is all speculation. It may explain why it appears to be a tear in time space?

Let me know what you think of my theories .

 

[Particle]

Anti(hidden)matter is the key, because it's faster then light speed.

 

[Particle]

Originally posted by: Darksamie

Hmm... I don't see a whole lot here on parallel dimension theory which could occur in going forward or back in time.

Basically you would be travelling through time to a parallel dimension, so you could in effect travel to a state before the time machine was built. However, you could never travel back to "your" dimension in time as there would be no way to plot a course to a dimension in an infinite number of dimensions.

This is linked to string theory and cross dimensional time travel as some people believe it to be the only way time travel would be possible.

Having multiple dimensions or "instances" of time also raises many questions about "god" etc etc as in effect there would be an infinite number of worlds are parallel universes etc etc so you could theoretically go through time forever and never get back to where you started.

If anyone wants more info on this or wants to debate further, weigh in and lets have some interesting conversation.

The spiritual realm is what controls these verses within the mutiverse. So we would have to control Anti-matter to 'know' where were going which we now have some capability of doing. I'm still not sure on how Antoi-matter relates to all of this. But I do know that Love anf faith have a large roll.
Use the force Luke.

 

[H20Cool]

Time is just our perception, it's purely relative and subjective. The Physical properties of the universe would literally have to change as we know them, for time to change and that would mean the physical break down of us (matter) and everything around us. Time really is the perception of the physical unfolding (expansion) of the universe. Thinking you can travel in time is like thinking you can change the laws of physics as we know them.

I could make a permanent magnet "magically" loose its magnetism, if I could change the laws of magnetic force. I could float in mid air if I could manipulate the laws of gravity. And indeed, we could travel in time if we changed the laws of sub-atomic force, but then, we would cease to exist, and so would the rest of the universe.

A book I highly recommend is "The Final Theory" by Mark Mccutcheon. A great read, and explains the universe in terms of it's simplicity rather than its complexity.

Now time "perception" is entirely different. You want to perceive time differently, just pop a hit of acid and have a good trip

 

[cecallred]

I found all of this fascinating. It brings up many more questions than answers. I have a question, being a layman in this, but is Time itself an entity? What I mean is that we as human beings have given time a mathematical reference based on tangible criteria, but is TIME an entity? Today, right now, it's 12:27 pm where I sit in Knoxville, Tn. tonight it will be some time, say 8:00pm, and I can see and measure that on clocks. The few hours that passed have passed for real and because I have accepted the illusion of time so that I can function in this world along side of all of you. .... But what is TIME? Does it exist purely within itself?

Cec

 

[Particle]

Originally posted by: cquark

Originally posted by: thereaderrabbit

Originally posted by: cquark

Originally posted by: thereaderrabbit
1. Thermodynamics states that entropy of a closed system can only increase with time... Entropy is build upon random movements at a molecular level... Most particles are without memory at molecular level... Thus you must reverse a random process that has no memory of it's initial state billions of times to go back only a few seconds of time... I don't think it's feasible.

You don't have to reverse a process to go back in time; you have to rotate your dimensions to swap your radial and time coordinates. Applying entropy to curved space-time is even more difficult than applying conservation of energy (see my post above for that problem.)

I don't buy this explanation (yet). Swapping your 'radial and time coordinates' would not seem so troublesome to me if it were not for the fact that radial coordinates are so complex (as you need three pieces of information to fully define a location of an atom and there are then an unimaginable number of these particles which make up the universe) and *most notably* there is not any reverse button for entropy on the molecular level (with few exceptions which include the field I'm studying - rheology). What I'm driving at is that any shot's you've taken my first theory seem to be oversimplifications of the physical world.

You're not changing the whole universe. You're just rotating your radial and time coordinates. No one else's coordinates are modified. We're not talking about rewinding the history of the universe, so entropy doesn't come into this in any way, even if we could define it consistently in a curved spacetime, which no physicist has been able to do yet. The universe is a four-dimensional object; all of those points in the past are still out there and available to be accessed if you have a time machine. The time traveller simply moves from one 4-point to another 4-point; nothing else is altered.

Yes, I am guilty of simplifying matters to a high degree. So are you by ignoring the differences between flat 3-dimensional space and curved 4-dimensional spacetime; however, that's an essential difference because time travel is impossible in a 3-dimensional flat space with separate flat 1-dimensional time, but is permitted in a curved 4-dimensional spacetime. That difference is also the reason why thermodynamics isn't the obstacle it would be in flat Newtonian physics.

It's true that the swapping coordinates explanation in a highly curved spacetime is a highly simplified explanation. There are a lot of details in how frames are transformed in the region of a black hole, and understanding Morris and Thorne's time travel paper requires a solid understanding of Lie algebras and nonEuclidean geometries. I've heard Kip Thorne's popular book Black Holes and Time Warps is good, but I haven't read it myself. If this post doesn't help you understand general relativistic time travel, perhaps his book would be a good place to look.

I really haven't read this type of material on the subject but am going to. I heard something about a 'Ten String Theory' one time that sounds like dimensions. I mainly get allot of this from Sci-Fi I read. Also I am a computer scientist and am working with multi-dimensional programs at the moment. Graphics and A.I.
My theory of the 4th dimension and beyond is that it is a control or 'spiritual unseen and intellectual' aspect that binds the lesser dimensions together to form a cognitive reality. The dimensional hands of God
So, with the fourth dimension you would be using intelligence or other means to generate relativity between a 2d or 3d room. Digital is high level and analogue is low level but both have existed since the beginning.

About Time travel,. it obviously exists in our everyday lives. First person in line, Sports competition. Sound waves. The question is :How to change reality sufficiently to control it.. Better computers(digital) efficiency(analouge). The more we digitize or catalog our universe the more we will be able to plot and alter it at the same time. The Alpha Omega Theory. I think Digital is higher level and analogue is low level.

I think we would have to evolve to a complete extent to have this type of complete control of our universe to some sort of Godlike existence. We can do these types of things with prayer and fantasy right now but I think there should be more control somehow.
With Light you can trace the beam back to it's origin and so discover what was happening previously because it emits in a straight line. But with general matter it would be impossible to do an analogous 'Back to the Future' thing without fully altering the universe manually. With that, all particles would have to be tracked with a computer. Example simulation. This is becoming more and more frequent with 3d computing. I heard someone that a 1 gig computer could track a sufficient amount of particles to do a proper simulation.

 

[Hayabusa Rider]

I'm not convinced that humans are smart enough to understand time, much less manipulate it.

 

[CrispyFried]

Larry Niven had in interesting take on this.

He argues that is may be possible but wont happen for the following reason, I hope I remember it right..

This assumes time travel is possible. I know this doesnt prove or disprove it as per the original question, just what would eventually happen if it was.

If its possible, we will eventually get to a point where it wont happen. This is because if it were possible, eventually future people would keep changing history. The change can go two important ways, creating a new time line where time travel were still possible because someone finds a way, or a time line where no one finds a way. If the former, it will keep changing until the latter time line is hit. Once that time line where no one finds a way is hit, it stays that way. We would be at that point now because in all the infinite future, all the changes would be done by now, and we are at the "no one finds a way" timeline.

edit: spelling

 

[cquark]

Originally posted by: Gamble
I really haven't read this type of material on the subject but am going to. I heard something about a 'Ten String Theory' one time that sounds like dimensions.

String theory typically uses 10 dimensions, but it's just math until we have some feasible experimental test for it.

I mainly get allot of this from Sci-Fi I read. Also I am a computer scientist and am working with multi-dimensional programs at the moment. Graphics and A.I.

If you like that sort of thing, try Greg Egan. His book Schild's Ladder has some interesting ideas along those lines, and he often has science references and Java applets on his web site to help readers understand and visualize the concepts he discusses in his novels.
http://gregegan.customer.netspace.net.au/SCHILD/SCHILD.html

I heard someone that a 1 gig computer could track a sufficient amount of particles to do a proper simulation.

We don't have enough computational power to simulate the inside of a proton. It takes a modern supercomputer to simulate a 32x32x32 volume (volume units are typically around 10^-15 meters) for lattice QCD.

 

[jdsemler]

I don't have a PhD or any other meaningful piece of paper to talk to this subject, but even if time travel was possible, everything in the universe is constantly moving and spinning. Wouldn't you risk ending up going forward/backward in time and having the Earth be somewhere else? Perhaps someone came up with a way to travel in time, but ended up just suiciding when they were violently killed at their destination.

 

[cquark]

Originally posted by: jdsemler
I don't have a PhD or any other meaningful piece of paper to talk to this subject, but even if time travel was possible, everything in the universe is constantly moving and spinning. Wouldn't you risk ending up going forward/backward in time and having the Earth be somewhere else? Perhaps someone came up with a way to travel in time, but ended up just suiciding when they were violently killed at their destination.

Fictional time machines have this problem as they tend to be time teleporters, where whatever's put into the time machine instantaneously changes its time coordinate to be at another year.

However, the types of time machines permitted by General Relativity work in such a way that that doesn't tend to be an issue. They require that you undergo a spacetime displacement, where you're transported in both space and time, instead of just allowing you to move only in time while keeping space constant. You also need a spacecraft to use a GR time machine, as they require large near-light velocity black holes or wormholes that are too large or destructive to place on a planetary surface.