Is it true that black holes can be used for time travel?
94500
The gravatational pull from a black hole is so strong that the likelyhood of an object being released is slim at best. The reason it is called a black hole is because gravity is so strong it even absorbs and disburses the waves and particals that make up light. Most scientists believe that even atomic coheasion is lost so that the smallest particals of the nuclious are torn apart.
1093002
the theories of time travel are extremely complex. it is often mistaken that one can use radiation or electro-magnetics to warp space into  an alternate reality. one of the popular theories of time travel is only from a certain point. what I'm saying is that we will not be able to visit this time from the future. \n\na few theories are;\n\n1: warping the very fabric of space, then accelerating to near the speed of light through the folds. the speed would then turn you body into pure energy, eventually reformulating somewhere in the future. Problems: 1; to warp space fabric would require more energy than it takes to make a black hole. 2; this is my personal theory.\n\n2: do you know how a worm-hole works? if not, ignore this section. but take an opening of a worm-hole and some how place by a point of high gravity (a neutron star). while at the same time directing negative energy at both openings in order to keep them from collapsing into a black hole. time slows down in super-high gravity, therefore if you throw yourself into the opening with no gravity, you'll wind up in the past. and vise-versa. Problems; 1; worm-hole technology is beyond our reach at this time. 2; worm-holes are flickering in and out of existence every infinitely small spec of time, therefore it is difficult to isolate one.\n\nas for what time travel exactly is, i could go one for about three pages.\n\nI'm a nerd. \n\nStargazer.
68159
it is not that confusing. About three year ago on PBS there was a program that talked about time travel and one of the scientist stated that even if we could travel back in time we coul donly travel up to the point when the time machine was invented.\nBut do not forget there are manyh theories about time travel. For instance the grandfather paradox claims that you could not travel back in time, but others say you can but in a different dimension.
945559
Relativistic time travel is possible. Time passes more slowly for an observer who is in motion relative to one that is at rest. The next trick is to define which is which, which is why Einstein won the Nobel Prize (although it actually wasn't for relativity, but that's another question).
721881
I dont think time travel is possible! Even if you were to go faster than the speed of light, it still takes time to get to where you are going. And that brings up another question, where do you go?? Do you zoom around the planet a few million times? Which direction? Does it matter, it still takes TIME to do it.\n\nJust for argument sake, lets say you could go back (or forward) in time. I dont know why you couldnt be seen, you just traveled to a different time and when you get there your there, just as if you were to travel to a different city.
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.
391887
yes you can. it takes you back in time...or you get to see the future..this is how time machines work.
630252
Teleportation. We at least have theory on how teleportation could work. If the universe under discussion permits of time machines, then no time machines will be invented. The noted s/f author Larry Niven wrote a couple excellent essays on these topics, which I recommend to your attention. They will provide all the information you could possibly need.
85344
Based on the relativity theory, there are many studies that are taking place to look into the possibility of traversing the time-space continuum.  As far as I know, we're not quite there yet.  But if and when we are, we should be able to tap into the theoritical "worm-holes" to go into different points in space without having to exume too much time.
303837
Time travel is possible when we travel forward not backward. IF you look to the history books there are no such thing of human come form the future. So that is the proof that has defined the theory that we can't go to the past. There are theory that we can move forward by using the method of speed. Once you increase the speed of travelling the time will change very fast, and you might be in the future. But to have that kind of machine to bring you forward needs a lot of discovery especially about the strenght of metal, fuel, speed, and a lots more. You can get the theory about speed from einstein. Whatever you want to know about it, you can get it there, BUT eventhough you learn about time travel, you won't get that technology while you still alive. Maybe you can use that information just for you knowledge. Not more than that.
551619
These answers sound pretty good.  However, if the fantasy idea were real and I looked up teleportation in the dictionary, which is based on common usage, I suspect I would find 'time travel' as the definition.\n\nWith my two cents, Teleporting would be a method of time travel, as opposed to others, I guess like OBE's.  I'm sure there would be more than one way to time travel by then.\n\nYou might not be the same person, Star Trek transported people out and back without their diseases or illnesses as a cure.  But if you did the sling-shot effect, using that method as opposed to teleporting you would be the same person.
558181
I haven't.But.......\n\nTime travel has been a popular science-fiction theme since H. G. Wells wrote his celebrated novel The Time Machine in 1895. But can it really be done? Is it possible to build a machine that would transport a human being into the past or future? \nFor decades, time travel lay beyond the fringe of respectable science. In recent years, however, the topic has become something of a cottage industry among theoretical physicists. The motivation has been partly recreational-time travel is fun to think about. But this research has a serious side, too. Understanding the relation between cause and effect is a key part of attempts to construct a unified theory of physics. If unrestricted time travel were possible, even in principle, the nature of such a unified theory could be drastically affected....
5272
A worm hole is a idea, not a proven fact. With that said, if a worm hole does exist, then its two points in space that are connected by a "shortcut" in the universe. Formed by a fold in space-time or bending of space-time via gravity or collapsed star or whatever. Anyway, it would be useful if somehow the ends could be controlled. If the ends could be controlled and moved this would lead to the time machine. Example, one end is taken at relativistic speeds away from earth and then returned, when it gets back you have a time machine. Because of the relativity effects, by going threw the "shortcut" aka worm hole, one could travel back and forth threw time. Of course the idea is just an idea and the technology needed may be impossible. Hope this is thought prevoking though!
938858
YES! Time travel is possible. For example, an object traveling at high speeds ages more slowly than a stationary object. This means that if you were to travel into outer space and return, moving close to light speed, you could travel thousands of years into the Earth's future.\n\nNewton's most important contribution to science was his mathematical definition of how motion changes with time. He showed that the force causing apples to fall is the same force that drives planetary motions and produces tides. However, Newton was puzzled by the fact that gravity seemed to operate instantaneously at a distance. He admitted he could only describe it without understanding how it worked. Not until Einstein's general theory of relativity was gravity changed from a "force" to the movement of matter along the shortest space in a curved spacetime. The Sun bends spacetime, and spacetime tells planets how to move. For Newton, both space and time were absolute. Space was a fixed, infinite, unmoving metric against which absolute motions could be measured. Newton also believed the universe was pervaded by a single absolute time that could be symbolized by an imaginary clock off somewhere in space. Einstein changed all this with his relativity theories, and once wrote, "Newton, forgive me."\n\nEinstein's first major contribution to the study of time occurred when he revolutionized physics with his "special theory of relativity" by showing how time changes with motion. Today, scientists do not see problems of time or motion as "absolute" with a single correct answer. Because time is relative to the speed one is traveling at, there can never be a clock at the center of the universe to which everyone can set their watches. Your entire life is the blink of an eye to an alien traveling close to the speed of light. Today, Newtonian mechanics have become a special case within Einstein's theory of relativity. Einstein's relativity will eventually become a subset of a new science more comprehensive in its description of the fabric of our universe. (The word "relativity" derives from the fact that the appearance of the world depends on our state of motion; it is "relative.")\n\nWe are a moment in astronomic time, a transient guest of the Earth. Our wet, wrinkled brains do not allow us to comprehend many mysteries of time and space. Our brains evolved to make us run from saber-toothed cats on the American savanna, to hunt deer, and to efficiently scavenge from the kills of large carnivores. Despite our mental limitations, we have come remarkably far. We have managed to pull back the cosmic curtains a crack to let in the light. Questions raised by physicists, from Newton to Kurt Gödel to Einstein to Stephen Hawking, are among the most profound we can ask.\n\nIs time real? Does it flow in one direction only? Does it have a beginning or an end? What is eternity? None of these questions can be answered to scientists' satisfaction. Yet the mere asking of these questions stretches our minds, and the continual search for answers provides useful insights along the way.
786311
You can travel to the past but you can not travel to the future BECAUSE it did not occur yet.\nCheck the latest Physics web sites on this topic of time travel
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.
127702
Black holes are full of electrons.They are not capable of any expansion or constriction. Time also does not expand.