I'm sure it is probably possible, but it has yet to be done. At least, to the knowledge of anyone who would leak it to the press. Several people have claimed to come back from the future. In March of 2003, a man was arrested for insider trading, and claimed that he was a time traveller and thats how he knew what to buy. He claimed to be from 2256 and there were no records of him existing before december 2002. http://tv.yahoo.com/news/wwn/20030319/104808600007.html John Titor is one of the more well known "time travelers." In late 2000/early 2001 he posted at several online "paranormal" website forums about how he was from the year 2036. He said that he came from "post world war III" America. Also, post-civil war II america. He claims that late 2004/early 2005 we break out in a civil war over the elections. If not true, his story is still a very interesting read. As well, he gives a few clues as to how his time machine works, plus pictures. This site was not done by him but by a "fan." http://www.johntitor.com/ I'm sure there are more. I know this doesn't answer the question of "how" but if I knew how, I wouldn't be here now typing this. I'd be elsewhere. Not sitting in 2004 about to see how true Titors story really is.

Suppose I was to make a time machine. I go back to yesterday and meet myself. So now there's two of me. Then we both go back to the day before yesterday and meet myself again. Now there's three of me. Then the three of us go back to the day before that...etc. Eventually there could be lots of myself. The above scenario is impossible because it violates the Law of Conservation of Mass, which says that mass cannot be created or destroyed. If there are suddenly two of me, that implies an increase in the amount of mass in the universe, which is impossible. Now you could say, "I'll go back to a time before I was born". That's no good either, because the matter that you are made of today, has been around since the universe began. No matter how far you go back, "your" matter will be there, and you will violate the Law of Conservation of Mass.

Possible? Almost certainly not. If it were, though, Einstein had some things to say about it... All paradox aside, the prime candidate is time dialation. Relativity states that as an object travels significant portions of the speed of light, it experiences a shorter amount of time than an observer at rest. As one approaches c, one's experienced time approaches 0. If one could go faster than light, mathematically one would be moving backwards in time. Good luck with that, though, since mass also increases with speed. The reason c is an absolute limit is that anything with any mass at all to start with would end up with an infinite mass, which would take infinite energy to accelerate past c. Of course, Einstein had his own problems with quantum theory. It's possible that, at some point, our understanding of quantum states will allow us to transport sentient beings into the past. As to who would be so recklessly irresponsible as to allow it, I suspect only some nations' governments would dare.

If one does exist, where are all the tourists? It is not possible to move backwards in time. Period. Even if we could, hypothetically, there are risks in doing so. Quite apart from dealing with annoying tourists slumming in the past. You can travel to the future, theoretically, but the technology isn't there yet. If you managed to build a vehicle that could travel at a relatively high percentage of C, over a suitably long period of time, looping out from the earth and returning to it, you would arrive in the future. Bon voyage.

There is a theory which may allow for time travel to occur but it relies on the existance of super dense strings of matter in space, the idea is that given all massive objects (massive as in having mass not as in being huge), for want of a better word "warp" space-time, with the extent of warping being in direct proportion to the amount of mass contained in the system; a super dense string would distort space-time in such a way that it would assume a "bowl" like form with the string orientated such that it emerged from the centre like an axle. If we can consider the "regular" passage of time as observed by us to be the standard frame of reference (as pointed out in earlier answers the passage of time is greatly affected by the velocity of the subject and the frame of reference of the observer) then this would be equivelent to moving along the flat surface around the edges of the bowl from point x on one side to point y on the opposite, we will call the person undertaking this route observer A, if however, we were to instead go down into the bowl at x and emerge at y it is possible, given the correct mass of the causal string, that the distance travelled could be shorter than the distance between x and y around the edge, we will call the person undertaking this route observer B Thus observer B who went down into the space-time distortion at point x in time and emerged at point y in time would get to y before observer B who followed "normal" time passage and would from B's perspective have gone forward in time.

Life IS a one way Time Machine. to modify the tempo or direction; now that takes some energy and a method to appily it.

.85 of C before you begin to see a signifigant change

also, every moment of time from every perspective has already \"happened\" as a probability in an infinite probability. if you could actualize visiting one of those other points in time now you would not be traveling in time but visiting the present long ago. same true for future.

if it was possible, then everything we see at present is how things would ultimately end up. if anyone did invent a time machine, they were most likely from the future and we would probably be seeing them sometime or other. but so far there has been no record or suspicion of anyone that might have come from the future/past, which will most likely be the ultimate outcome.

Get a waffle maker, a few light bulbs, an aluminium hat, several electrical leads, a 12V battery, a few toggle switches, a handful of capacitors and relays, some old television circuitry and a good amount of super glue. Oh, you wanted a real one? Sorry, they don't exist.

A time machine has already been invented long ago. It's called a camera. Go look at a photo of your great grandfather taken in 1911.You've went back in time. Or look at a picture you took yesterday-Same thing.Or an old newsreel. If someone did invent a machine that would actually transport your body back in time the results would still be the same. All you would be able to do is stare at wherever or whatever you're at. But of course this would be a lot more interesting (seeing it "live")But you will not be able to do anything or change anything. I believe this will be possible someday because I believe everything living or inanimate leaves a photo-like negative behind. (Or an energy-field image if you prefer)--Once we have a machine that can develope these "images" you will be standing right in the middle of a Civil War battle. Or you may be watching Lincoln shot. But it will be like a movie. You would no more be able to warn Lincoln than if you were trying to warn an action hero on film of a bad guy sneaking up on him.This is admittedly a simple explanation of my theory and ther's a lot more to it of course. As far as traveling to the future,I won't say it's impossible but it would be a horse of an entirely different color as the future has not happened yet. At least as far as we know.

greatestgranddad is exactly right.

go check area 51, they probably have something like it there

Sure they make time machines. You can buy them just about any where, Wal-mart, convenience stores, flea markets and they go by two names, clocks and watches. :-)

If a person wants a time machine they should consider the aspect of Soul travel if they believe in that type of spiritual practice.

i dont think so but you can try inventing one