james44028 :

Ha ha! I actually tried building a time machine too, but I guess my theory was wrong...

Actually, I think it is theoretically impossible for HUMANS to Time travel, but it is very, very possible for GOD to do so since God is not bound by it. It's like a river with a really strong current: you just have to go with the flow and you can only choose where to land if you were outside of it at first.

I do not believe in time travel simply because almost all physics we know would have to be changed if  it did, but I do like thinking about what you could do if it was possible.

yoyogamr : There is nothing in the Laws of Physics about going back in time.

Oldschool41 : Paradoxes can quite easily be prevented if it was possible as long as we all follow the Doctor's rule: we just watch, unless there are crying children. Actually, strict rules would have to govern the potential of paradoxes and their creation. Just going back would be a paradox in itself- the air you breathe should go in someone else's lungs, that sort of thing. I don't see how to get past THAT particular problem, but other than that, I do not think paradoxes are that big of a deal in time travel unless someone is like Marty McFly and stop themselves from being born.

I think that it could eventually happen but the only way we could know if time travel was invented was if a time traveler came back other than that there is no other way we could know.

Dragonlord Stephi :

"There is nothing in the Laws of Physics about going back in time."

Actually, there is. The entire world of physics is derived from calculus equation. Our world is in 4 dimensions, time being one of them. We put rules of how everything in our Universe behaves in equation format. The thing that pretty much governs the way everything in this Universe works is gravity. Gravity shapes the behaviors of all energy and matter, and the dimensions of our Universe, time included. In the equation of gravity's effect on time, the stronger you make gravity, the more it bends time itself. So in essence, the stronger the gravity, the slower time itself moves. I will explain this in a more tangible example. Keep in mind that this example is very exaggerated just to simplify it.

Lets say you have a twin (because they would be biologically the same age as you). Both of you were given a stop watch. Your twin will stay on Earth, and you are instantly taken to Jupiter (I know it is impossible because it is a gas planet, but this is hypothetical). The moment you  are in Jupiter, both of your stopwatches start at the exact same moment. The stopwatches are set to end at 315,360,000 seconds (10 Earth years). The moment your stopwatch reaches that time, you will instantly be brought back to Earth. As far as you can tell, you were gone 315,360,000 seconds, and have aged that much. You are brought to your twin. You would see that your twin has actually aged considerably much more than you. When you compare stopwatches, you will see a lot more seconds are on your twin's stopwatch than yours. That is because Jupiter has a higher gravity than Earth. The stronger the gravity, the more it bends time itself, which means the slower time travels. Now, like I said, this is very much exaggerated. Though Jupiter's gravity is stronger than Earth's, the difference in their gravity is not enough to show any noticeable difference in time. This was just an example. So imagine we actually knew of a place that had gravity strong enough to where if you spend 315,360,000 seconds (10 Earth years) there, 100 years would pass on Earth. Where you are, time is moving very slow. But you don't notice it, and everything seems the same. But you spend what seems to be 10 years there exactly. You go back to Earth in an instant, and you will see that everyone that is alive when you were in this other place is dead and their children are middle aged to elderly adults. But you only aged 10 years. So technically, if you stayed there all your life, you would live for 900 years in Earth's perspective. But to you, you only lived for 90 years. Time is moving slower. If someone from Earth were somehow able to observe you in this place, you would be moving so slow to their eyes that you would appear to almost not be moving at all. But there is no known planet that has a high enough gravity for this to happen.

There is only one known thing in our Universe that has a strong enough gravity that, when plugged into the equation, would have a noticeable difference in the rate of time. That would be a black hole. Now, a lot of people thing that a black hole is some crazy portal through time itself. That is just silly and pure science fiction. A black hole is a place of immense and incomprehensible strength of gravity. it is so strong that it sucks up light itself. That means that being pulled inside would make your energy travel faster than the speed of light. The speed of light is the speed in which time essentially stops. In terms of the equation, the speed of light is the point where time hits 0. If you were traveling at the speed of light, everything would seem normal as far as time goes. But to everything else looking at you, it was as if time has frozen completely for you. Again, it is like the point in the equation where time is 0. Since light is sucked into a black hole, that means the gravity is strong enough to make the energy go even faster than that. Plugging that kind of force into the equation, it is like a variable amount that puts time into the negatives (simple way of putting it). This is the point of singularity where time and space are essentially meaningless. As Lazlo stated a long time ago here, that would be where energy would be popping forward and backward at time randomly. 

The thing is, humans are not pure energy. They are matter. Matter cannot travel the speed of light or faster. The speed of light is the speed in which matter is converted into pure energy. This is the meaning of Einsteins most well known equation e=mc². If you reached the speed of light, your physical body would essentially be vaporized into pure energy, meaning the process would kill you. 

So to sum up and restate, the Laws of Physics to specify the concept of time travel. However, it is not testable. It is pure formula derived. The concept is in the math. It works in the mathematical equation of how our Universe behaves and works. Now, the idea of people traveling forward or backward through time and holding their physical body and living is science fiction. But the actual concept of time travel itself is not.

Dragonlord Stephi :

"There is nothing in the Laws of Physics about going back in time."

Actually, there is. The entire world of physics is derived from calculus equation. Our world is in 4 dimensions, time being one of them. We put rules of how everything in our Universe behaves in equation format. The thing that pretty much governs the way everything in this Universe works is gravity. Gravity shapes the behaviors of all energy and matter, and the dimensions of our Universe, time included. In the equation of gravity's effect on time, the stronger you make gravity, the more it bends time itself. So in essence, the stronger the gravity, the slower time itself moves. I will explain this in a more tangible example. Keep in mind that this example is very exaggerated just to simplify it.

Lets say you have a twin (because they would be biologically the same age as you). Both of you were given a stop watch. Your twin will stay on Earth, and you are instantly taken to Jupiter (I know it is impossible because it is a gas planet, but this is hypothetical). The moment you  are in Jupiter, both of your stopwatches start at the exact same moment. The stopwatches are set to end at 315,360,000 seconds (10 Earth years). The moment your stopwatch reaches that time, you will instantly be brought back to Earth. As far as you can tell, you were gone 315,360,000 seconds, and have aged that much. You are brought to your twin. You would see that your twin has actually aged considerably much more than you. When you compare stopwatches, you will see a lot more seconds are on your twin's stopwatch than yours. That is because Jupiter has a higher gravity than Earth. The stronger the gravity, the more it bends time itself, which means the slower time travels. Now, like I said, this is very much exaggerated. Though Jupiter's gravity is stronger than Earth's, the difference in their gravity is not enough to show any noticeable difference in time. This was just an example. So imagine we actually knew of a place that had gravity strong enough to where if you spend 315,360,000 seconds (10 Earth years) there, 100 years would pass on Earth. Where you are, time is moving very slow. But you don't notice it, and everything seems the same. But you spend what seems to be 10 years there exactly. You go back to Earth in an instant, and you will see that everyone that is alive when you were in this other place is dead and their children are middle aged to elderly adults. But you only aged 10 years. So technically, if you stayed there all your life, you would live for 900 years in Earth's perspective. But to you, you only lived for 90 years. Time is moving slower. If someone from Earth were somehow able to observe you in this place, you would be moving so slow to their eyes that you would appear to almost not be moving at all. But there is no known planet that has a high enough gravity for this to happen.

There is only one known thing in our Universe that has a strong enough gravity that, when plugged into the equation, would have a noticeable difference in the rate of time. That would be a black hole. Now, a lot of people thing that a black hole is some crazy portal through time itself. That is just silly and pure science fiction. A black hole is a place of immense and incomprehensible strength of gravity. it is so strong that it sucks up light itself. That means that being pulled inside would make your energy travel faster than the speed of light. The speed of light is the speed in which time essentially stops. In terms of the equation, the speed of light is the point where time hits 0. If you were traveling at the speed of light, everything would seem normal as far as time goes. But to everything else looking at you, it was as if time has frozen completely for you. Again, it is like the point in the equation where time is 0. Since light is sucked into a black hole, that means the gravity is strong enough to make the energy go even faster than that. Plugging that kind of force into the equation, it is like a variable amount that puts time into the negatives (simple way of putting it). This is the point of singularity where time and space are essentially meaningless. As Lazlo stated a long time ago here, that would be where energy would be popping forward and backward at time randomly. 

The thing is, humans are not pure energy. They are matter. Matter cannot travel the speed of light or faster. The speed of light is the speed in which matter is converted into pure energy. This is the meaning of Einsteins most well known equation e=mc². If you reached the speed of light, your physical body would essentially be vaporized into pure energy, meaning the process would kill you. 

So to sum up and restate, the Laws of Physics to specify the concept of time travel. However, it is not testable. It is pure formula derived. The concept is in the math. It works in the mathematical equation of how our Universe behaves and works. Now, the idea of people traveling forward or backward through time and holding their physical body and living is science fiction. But the actual concept of time travel itself is not.

I think it is indeed quite possible. We need to first develop the technology capable of doing this first before we can attempt it. I think it is very possible and I do believe in it. I also think that it is dangerous as well and there are many problems that will follow with attempting time travel. There are many things that we have to take into account when we attempt this.


I agree with everything rcarter said, it all makes sense, the only place where gravity is at its most powerful is in a black hole, where the immense strength is enough to suck in light itself without it being able to escape. It works in such a way that mass is linked to space in a way that physicists still don't completely understand. However, we do know that the stronger the gravitational field of an object, the more the space around that object is curved. That means that straight lines are no longer straight if exposed to a strong gravitational field: instead they become curved. Since light travels in such a way, it will travel in a curved path when it comes in contact with a strong gravitational field, this is what is meant by 'curved space' and this is why light becomes trapped in a black hole and cannot escape it.

No. I think that it is just something that can't be done. Doing it would mess with Time-Space  and that wouldn't be good. But you could make gravity that is higher then a black hole. It will be done. Oh, gravity higher then a black hole, not time travel. 

Razor-987 : You seem to misunderstand my explanation. Light isn't sucked in because it's strait line path is curved in the event horizon. Light, though behaves much as a wave, it still has they physical characteristics of particles, which is matter. It is just like when you throw a ball while standing on Earth. For a while, it has enough speed and trajectory to overcome the gravitational pull that is pulling it down to the ground. But it does slow down to the point to where it's speed is not enough to overcome gravity, and is pulled down. Same aspect here only in reverse. Light travels strait. As long as it does not pass through the Event Horizon, it's speed is enough to overcome the gravity of the black hole. But the event horizon has a gravitational pull stronger than the trajectory of light at it's speed. So the light gets pulled in. It isn't because of some concept of strait lines becoming curved lines or strait paths being curved paths. 

But the thing is, we can't have the technology to do this. There is no object that can withstand that kind of gravity without being stretched, vaporized atom by atom, and converted into pure energy. Any technology we come up with will be made of matter. Light can't escape without being crushed, and that is going literally the speed of light, which matter cannot do. And that doesn't change the fact that we are made of matter, and we would be vaporized into pure energy, which would kill us. It is how our Universe works. Matter can't hold in that strong of gravity. The only reason why I summon you here to tell you this is because you said you agreed with what I said, but misrepresented it.

Yes, I do to a certain extent. I believe that someone has the ability to create it, but I don't think it would happen anytime soon. I really wish it would happen soon because I want to go back in time and tell my stupid self not to do certain things. But, it would be pretty cool to jump into the future just as well. 

No, I don't believe in time travel. I know that it will always be impossible to travel to an earlier or later time. I'm sure that if time travel did exist in real life (which it doesn't and never will), if one person tried to turn back or fast-forward time it would completely erase everything from the present time to the time you go back or forward to and it will wipe out you as well. I sometimes imagine the possibilities of what it would be like to time travel, but I don't actually believe in time travel in general.

PacmanandMariofan : Although messing everything up would only be if time were linear like a river. But if time were not linear, that would indicate that changing something in the past would only create a whole new timeline. For example, if someone saved Hitler, there would be this timeline where Hitler died and the other timeline where Hitler didn't die as he died here. Although the math works for the idea of distorting time, I'm not sure i am as convinced in the aspect of non linear timelines. 

I believe in Time Travel because I remember about a year ago that my science teacher said the scientists are working on moving particles through solid objects faster than the speed of light, and the scientists are trying to prove if that particle really did travel faster than the speed of light, if it did, then that means you could go super fast and maybe travel through space time. Or you could teleport, which ever comes first. =]

On most days you might not credit gravity
with anything more than keeping your feet on the ground, but a
gravitational field can also warp time. That's gravitational time
dilation in a nutshell, and for an example of time dilation in action,
we need look no further than the nearest geosynchronous satellite. Even
with ultra-precise atomic clocks, these satellites would inevitably wind
up a few microseconds fast without correctional programming. This is
because massive objects such as suns and planets warp time. Yes, time
passes a little slower on Earth than it does in orbit. It would pass
even slower on the surface of a Jupiter-sized planet and get slower
still near a black hole. NASA even purposely "misadjusts" the clocks
before liftoff on space shuttle missions, so that time on the shuttle
will sync properly with time down here on Earth at the space center. GPS
satellites make similar time adjustments, because if they didn't we
would all get lost pretty easily when the calculated location in our
car's mapping system comes out wrong. All of this gravitational bending
and warping factors into Albert Einstein's theory of general relativity

yes
Because if you think about it maybe time travel requires two machines acting as doors
I wont be able to travel in time until to exist at a time and I cant go back in time before the door existed

No I don't believe in time travel and I don't think we will ever be capable  of traveling in time because time isn't a place nor does it have a physical form of structure, time is just a perception to which we use  measure life spans and periods of events.

The Ender's Game series has an interesting concept on a sort of "time travel". I'd like to believe that that kind of travel, forward, is possible. I doubt backwards time travel is anything but fantasy, though.

Hell yeah,You can Travel time exept if you Run at least 44000 miles in hour which mean
You break up the speed limits and have a crack in time (not that crack you think)..
Witch lead you to Random place and time ..

rcarter2 : Now that I think about it, I read something similar about Einstein's relativity. The famous picture of the balls distorting a grid comes to mind, the balls being matter and the grid being the time-space continuum.