Is it possible to build a time machine??
455592
Some people like to wear time machines on their wrist.
502465
There is no such thing as time travel, it's a physical impossibility. The reason we haven't had any visitors from the future is because time travel simply cannot occur.
813626
Sadly, I've actually heard about this before.  I can't believe how much useless junk I put into my head...I'd say pure fiction.  Its just more likely that he was some bored computer geek trying to get some attention.  Its still unclear whether or not time travel into the past is possible.  Based on current science I'm leaning toward the impossible side.  Oh well, 2036 will be here soon enough.  Then we'll know for sure.   ;)
226037
I dont think So\n\nIt is possible only Physicaly not through any command.
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.
752397
I would go to the distant future and speak with people who perhaps allready have the time machine so I could understand how to use it carefully without disrupting the continuum. I would be careful on going to the future to get reports on sports games and the stock market because each future you visit is only one particular future, and with each passing second it creates a completely differrent future. I also might take christians and other religeous fanatics to the far distant past to prove to them that evolution occured once and for all and their bible thumping is basicaly meaningless. However this could also be dangerous because any foreign disease on us, or exhaled by us that was exposed to the primordial world could totaly change what we know to be current history. Every invention created by us happens very carefully, we make nothing before we are ready. If (in total speculation) a future time traveller visited the past he would have all precautions accounted for, such as disease, mistakes, and keeping a low profile. In our century we have no such precautions. So if I ever did get a hold of a time machine, I would return it to whoever it came from. Another problem with using a time machine to change the past or "the grandfather" paradox is Richard Feynmans theory of "a particle will take every possible path in space time" meaning if I went back and changed a past, I would change the past in a totaly differrent time frame then the temporal continuum I am used to, so when I returned everything would be the same. However I would be still messing with the universe. Theirfore if I ever found a empty time machine I would indeed leave it alone, or return it to the big temporal lost and found. We are not ready for such technology, and probaly wont be for a long time.
114656
It's not necessarily impossible according to theory, but given our current technology, it's out of the question.  There's a lot of trouble with time travel theory, including multiple paradoxes.\n\nThe most famous paradox is, of course, the grandfather paradox.  It goes something like this: One day, after you've built your time machine, you decide to travel back into the past to shoot your grandfather before your father is born.  Here is the major paradox, if you suceed in killing your grandfather, you couldn't be born to go back and shoot him.  Just as well, the conditions required for you to shoot him couldn't exist and thus he lives.\n\nStill on the 'travel back in time to shoot grandpa' string, several other things could happen as well.  You could be transported to an alternate timeline, similar to ours, but not ours, and whatever you do there doesn't affect anything in our time line.  You could go back and try and kill your grandfather, but you are thwarted in every attempt, which tends to imply some sort of destiny or grand scheme.  You could try to go back in time but are ripped to shreds because every fragment of your being wants to be in its natural time.  There's a million and one other things that could happen.\n\nThat, I believe, is not necessarily answering your question, though.  Time itself is not understood by physicists even now.  What it is, no one is quite sure!  (However, I'm fairly certain time is related somehow to mass.)  One thing that's always for certain is time moves forward in a very linear fashion, cause followed by effect otherwise called casaulity.  I can't say one way or another why exactly we can't go back in time and I won't say it's not possible, some theories say it is.\n\nHowever, I believe Stephen Hawking offered up the best proof against time travel to date: Wouldn't there be time tourists from the future visiting us if time travel was feasible?
1144162
Actually, the current theory on time travel is that the furthest back into the past you can travel with a time machine is to the point that the time machine was created.\n\nAccording to this theory, to travel back into the past, you would need to create two worm holes.  One wormhole would exist at the time that you turn on the machine and the other worm hole would be put somewhere to 'age'.  At some time in the future, something could be put into the wormhole in the future and it would come out in the past.
312777
Yes, there's still research going on. And yes, the theory still holds that if we could find a wormhole and create enough anti-matter to widen and stabilise it, and then find a way of surving the journey, time travel might be possible.\n\nBottom line, everything that's a theory today will either be proved or disproved somewhere down the line. Some things, like wormhole time travel and single-lifetime interstellar travel are the scientific equivalent of steeplechases - races with big old obstacles in the way. They might seem impossible at the start, but once you start running, you either have to figure out how to leap over the obstacles or fall down at them. But human beings are good at steeplechasing - look at the challenges we overcame between 1899 and 1970 - we couldn't fly when the century began. By the time we were seventy years in, not only had we fought two world wars in the air, we'd successfully landed on the moon. Who knows what we'll achieve by 2070...
46433
Nope....if it were possible in the future, someone would have come back by now, and brought the technology with him.  hasn't happened yet, so it's a no-go
155292
See my answer to the question "Is time travel a possibility?" especially the part about other universes
1156662
No we cannot. The time travel stories are our over enthusiastic mind's work. It just cannot be possible. Unless we attain speed of light. Do u believe in relativity? think about it... maybe u will find answers there.
1152196
I think it could be possible. Even though some people ask why someone doesn't come back and tell us this, if you came back in time and told everyone this, how would you know what effect it would have? What would probably happen it that they when it's invented, nobody will be able to use it, and then it might as well not exsist. There's irony for you.
887827
Time travel is possible. Theoretically.  According to some theories, there are random tears in the fabric of space-time.  Some researchers have even interviewed people who have had experiences of "lost time" and weird visions such as seeing things that were there one moment but gone the next only to find out that the particular thing they had see there only exsted in a time before.  For a better explanation you should visit http://paranormal.about.com/library/weekly/aa040802a.htm
84170
the answer is - it depends - on a lot of things\n\nI hate to answer a question with a question but here goes ...\n\n- do you mean in theory or in practice ??? (in [einstein's relativity] theory it is possible to travel into the future - all you need to do is to go out into space for a while - the time here on earth will continue to progress at a normal pace while time for you will progress more slowly - when you come back you'll have essentially traveled into the future - not quite a time 'machine' but same effect
56785
Yes, time travel is possible. :)\n\nIf you put a person in a rocket that can accelerate up to near light speeds on a round-about trip, when this guy comes back, he'd have aged much lesser than the guys who sent him. So he has travelled forwards in time.\n\nTravelling back in time is also possible. Oscilatting in time is possible. Time statis is also possible. All if we imagine a universe that has only a few elementary particles.\n\nHow? Well imagine a universe that has only a pendulum that swings back and forth. Now, we, as observers of this pendulum, can make the following observations, all different, and all "correct"\na. The pendulum is swinging back and forth as time advances\nb. The pendulum swings forth, then the direction of time reverses, and the pendulum goes back in time and swings back\nc. The pendulum is swinging forth and back as time retreats\n\nWhich of these is correct? We can't answer that question. So we can choose any one - it doesn't matter. These three are just different ways of looking at the phenomenon.\n\nYou may also want to read up about Feynman's diagrams
239506
Mr. Question's answer is baloney - a tell-tale sign is the complete lack of sources "a scientist in a northwest university"... give us names and places, please! \n\nAnyway, if you're interested in a "real-life" time machine, you need to look at General Relativity, in which time (being a dimension in space-time) can be warped in the presence of gravitational fields. However, you'd need a gigantic, massively heavy, incredibly quickly rotating object in order to warp spacetime enough to make any kind of dent in the passage of time.