Why ask if time travel will ever be possible?It already has happened.?
339701
Time travel occurs everyday with everyone.  Just sitting in front of the computer now I am advancing into the future at a rate of one second per second.  What the clock on the jet experiences is time dilation.  This simply means that for the clock on the Jet, time slowed down.  In this sense it is possible to travel into the future.  This would be done by travelling at extremely high speed.  This would essentially "fast forward" you into the future, but is a one way ticket as there is no way back.\n\nTime travel as a sci-fi concept (e.g Dr Who or Back to the Future) is not possible (as currently thought), as this would mean travelling into the past as well as the future.  There are some theories that could allow time travel into both the future and the past  However, in these theories, you could not travel futher back in time than the instant the time machine was built - the reasons for which are complicated and stop paradoxes from occuring!
1092955
First off, there's the famous Big Paradox:  Suppose you have a time machine, you go back 80 years and accidentally kill your grandfather before he meets your grandmother.  Whoops!  Now you'll never be born!   So you won't kill him, so he'll meet your grandmother and you'll be born and you'll kill him, so you'll never be born and ... See?  That represents a big problem right there, not just with your grandfather but with events in general.\n\nSecondly, as has been noted, if time travel were possible, don't you think that by now we'd have had visitors from the future?  (And no, I don't think they're sneaking around in disguise; why would they?)\n\nFinally: in the universe as we know it, we experience time in one direction only.  If you don't like the way a movie ends, you can rewind it and watch it again, but the ending won't change no matter how many times you do it, or how far you rewind before pushing 'play' again.  So, make the most of time as you move through it.  You won't be able to change it later, so enjoy it now and do things you'll enjoy revisiting in later years with your own 'internal' time travel -- memory.
1102835
Nope.  There is no time like the present, so why waist it waiting.
18327
If you would belive in the parallel universe theory\nthere is a possibility that the past exists in a \nanother parallel univerese.However if you would\nbelive in the space-time continum,the past would\nnot simply exist as would the future.But theoriticaly\ntime travel is possible is you consider slowing down\nthe rate of time advancing but this will not lead you to the past but it would take longer you to reach the future in your particluar reference of time\n,here relativity comes into picture and the solution is still not clear.
71991
cool question ! i dont believe in time travle , and thats a good point ! thanks
290592
*Edit*\nSorry for editing again!\nTo answer your questions. Yes the past still exists! But objects in the past have a fixed (p,q,r,s,u,v,w,x,y,z,t) location (where each letter represents another dimension in space, t = time). To realise this, think about where you were last Friday at exactly 4:00pm. You're position at that time will never change again. Wherever you were, that's where you'll always have been last Friday at 4:00pm. The rest of this post explains why you cannot go back to that time without dramatic changes in your string physiology, but that time travel may be possible for some types of matter (possibly supersymmetric matter?). Unless matter has moved backward along the time dimension, it cannot move forward, because the time dimension is expanding along with the rest of the universe.\n\nI had this discussion on a drive up to play hockey in Edmonton the other day. Here's my idea but I don't know if it is true:\n\nYes, time travel is possible. Time is just like the three other open dimensions we are used to - you can travel back and forth along the 3 space dimensions and it is possible that things (notice I don't say people, keep reading to find out why) can move back along time. But as far as I know, the four dimensions of space and time do not have radii like the 5-11 compactified dimensions of M-Theory do. Therefore something travelling in time cannot loop back to the same place in time that it was before. Thus you could not go back in time and have yourself arrive at the same place in spacetime that you are today. The dimension is linear.\n\nThe MOST important part of this is the idea of symmetry breaking. In my mind, symmetry breaking accounts for why something traveling back along the time dimension will not encounter the same events that originally occurred when it started it's motion along time. Symmetry breaking is a time dependent event. The easiest way to explain it is to reference the poem "The Road Not Taken" by Robert Frost. Events in time diverge at critical points (usually at critical values for state variables like temperature). Travelling back in time would cause disorder of various aspects of energy and matter in the universe, and different bifurcation paths, or "decisions", might occur, effectively changing the future in ways imperceptible to things that are made up of baryonic matter, which leads me to my final point.\n\nThe only objects that could time travel are those made up of closed, unattached strings. The strings of ordinary matter, like that which we are made up with, are open ended and attached to dimensions. This is why the mass that makes up us and objects like the sun distort spacetime. Time actually travels slower as you approach mass, and this is what causes masses to move toward each other. Time gets warped and masses fall towards spacetime that is in a lower transient state. What makes us up is effectively 'attached' to time, so unless we could change ourselves to be made up of matter of closed loop strings, we cannot attach ourselves from time. This also means we cannot leave our universe either, but that's another story.
1090
Causality prevents information from traveling "backward" in time, and is the most sacred tenant in physics.  Relativistic time-dialiation (above) is certainly interesting, but there is no time-travel theory (quantum or otherwise) that won't be met with anything but snide remarks by a real physicist.
519456
There are some strange solutions to Einsteins field equations which some theorists claim to offer the possibilty to travel backwards in time but these are pure hypothesis.\n\nFor one of these possibilties you would need a huge amount of "strange matter" which we yet even don't know what it is exactly, other of these hyothesis would allow to travel back in time, but not past the invetion of the thime machine, since this time machine is the "exit" on the other side of the "time tunnel".\n\nOther scientists say it will never be possible, for varios reasons, one of the most mentioned is the problem with causality (althogh there are again theories that that would't be a problem) another very funny one is by Stephen Hawking: There never will be time machines, becaus if it would we would see tourists from the future all the time.\n\nSo, seriuosly, don't expect to see a working time machine during your lifetime.
855043
It's all theory, we don't know if (something) can exceed the speed of light. I would argue that time would be void at that moment, but again it's my theory. Interesting thought though.
1005289
You have just described the concept of temporal paradox.  This is a central theme in time travel science fiction.  If you travel back in time and kill your grandfather, how then can you have ever existed?  Well, the most common explanation is that we exist in a "multiverse" where many realities coexist simulaneously, and when you "travel in time" you actually traverse to a different reality where your actions have no bearing or effect on the reality that you came from.  Each new change, choice, or action spawns a new reality...
355289
it is believed by many time travel is not only possible but that it has all ready begun. look up time traveler john teeter or it may be john titor .tell me what you believe the truth is that you see
734390
Theoretically, time travel is possible. But current technology does not permit it. An interesting article appeared in Popular Science a while ago on time travel physics (see link). You're right about the stars - in that we're not looking at them in real time. In a similar vein, light from the earth reaches outward into space. An alien civilisation looking at us from far away through a telescope could theoretically view our past history. But light also weakens the further it gets away from its source, so to really look way back into our past, we'd need a really powerful instrument to detect such light patterns.
50535
OK, first fo all Mr cliffx has it backwards.  As you continue to acellerate tworads the speed of light time will slow down for you and stay normal for everyone else.  Thus at that speeds you could travel 10000 lightyear in only 1 year, your lifetime, but thousands of years could pass on earth.\n\nIt has been theorized that time travel is posible but you could not simply accelerate to that speed.  Even if we could travel that fast the economical need would be currently beyond what any country has, even if they put all there funding into that one project.  but I am getting off the subject.\nOne theory is to travel into a black hole.  The gravetational field in a black hole is so strong that it has been theoryzed that even time cannot escape.  Thus if we were able to travel into a black hole we could use the captuered time there, so to speak, and transverse the timeline.\n\nThen there are ideas of actually traveling on light waves, lasers, to allow us to travel to the speeds necisary.  Of course then we could only travel to the time of how long that peice of machinery is on.  Also we would have to convert ourselvesinto an electrical signale, data (essicially transport), which would then bring up the promblum of measuring matter without moving it and blah blah blah.\n\nSummery, Yes it is possible to travel through time.  We just do not havet he knowledge and/or technology to do it yet.
164691
According to Einstein, it's only possible to travel time to the future, although he never said that going back in time is impossible.\nTime slows down for you and your vechicle as you travel close to the speed of light (186,000 miles per second).  Anything outside is at normal time and speed obviously.\n\nTheoretically, if you travel 30 mins out into space at the speed of light and travel back to earth, you're only an hour old (by the way, at that speed, you've traveled an equivalent of six of our solor systems).  However, as you return to earth get ready to meet your great great grandson.\n***\nI don't know why.\nIf I did I'd own this freaking corporation.  *L*
386007
yes, and that's why it's impossible to time travel (no going past the speed of light either)
1068787
travel into the future is possible by einstein theory as one approaches the speed of light.  \n\nTraveling into the past is a different story though, access would have to be open from the past for this.  There is no way to create a portal to the past, someone from the past would have to create the portal to the future where the future person could pass.  \n\nIt is argued though that this would only open a door to another dimension and another universe independent of our own universe.  If you think about it, the fact that someone could 'travel' to the past is direct evidence that other parallel universes exist.  If you were to travel back into time history and events would inevitably be changed from occurences known to us in the present, therefore you must be in another universe.  \n\nAnother way to see the past is to create a large gravitational force bending space time such as a blackhole, and align it so that the light traveling from where you are would be bent back to a location where you could observe it.  This would be like viewing T.V. though, because you could have no interaction.
186420
Time travel seems to make sense to us because we have the concepts of past and future.  In particular, we can vividly picture in our minds the parts of the past we have experienced.  The past can seem to have a kind of reality because of memory, as the can future because of imagination.  But, neither the past nor the future have any real existence.  There is only the present.\n\nTime is not a container like space is.  We can travel in space because other places really exist.  Time is not a container.  There's nowhere to go.  So, no, time travel is not possible.