Are ther any laws in Physics that totally rule out the possibility of time travel?

Question

To Kaiser:Yes,but if there were some kind of way we could cross into a parallel dimension and cross back,would that not contradict any laws?

Answer 1

Conservation of mater and energy. The law states that at any given time, the total mater and energy in the universe must remain constant.

To get around this problem, you could say that when you traveled back in time, you would have to simultaneously move the same amount of mater forward in time, and visa-versa. You could also get around this problem if you said that energy was added to the point of origon and removed from the destination.

There are some entropy laws that might be violated.

Answer 2

Most, if not all of the "laws in Physics" that prohibit time travel have been sited in your other answers. I'd like to add this scenario to them:

I light a candle at 10:00 am. At 11:00 am the candle is burned out - a slab of limp, molten wax dripping off the table.

I then travel back to 10:00am and, this time, I don't light the candle.

In what condition would I find the candle when I traveled back to my original time of 11:00 am? And where did the time I was gone go if I left at 11:00 am and returned at 11:00 am? Did time just atop and wait for my return? If so, did it affect anyone else? And, if it didn't, is everyone else in the future now?

It is this type of paradox that absolutely rules out any realistic hope of time travel.

I know full well that simple common sense isn't always a good indicator of the workings of the universe, but I sincerely believe the notion of time travel is an exception.

Answer 3

No there is no law that rules out time travel, only explanations to laws like exchanging matter and energy, time travel is just warping space and time wich giant bodies like black holes do everyday but you may end up in a parallel universe.

Answer 4

I agree with Michael. One of the laws in thermodnamics states that the total entropy of the entire universe has to increase and hence entropy is used a time arrow in a way. Traveling backwards in time wuld contradict that.

Answer 5

Einstein's famous E=mc^2 basically rules out this possibility. He postulates that an object would have to travel faster than the speed of light to travel backward in time. E=mc^2 makes this an impossibility because it implies that as an object's velocity increases, its energy also increases (kinetic energy=.5mv^2). Because E is increasing, the object's mass must also be increasing to satisfy E=mc^2. For an object like a car, this mass change is miniscule because its velocity is so much smaller than the speed of light. But as an object gets closer and closer to the speed of light, its mass gets larger and larger, and therefore it takes more and more energy to increase its speed. Essentially this means that it would take an infinite amount of energy to accelerate an object with mass to the speed of light, because you would never quite be able to break the barrier.

Hope that helps answer the question.

Answer 6

Well considering that we are already traveling in time, I don't think so. I have always thought that if someone could cross the ERP Bridge to another dimension, a dimension whose time is in reverse of ours (ie. anti-time), you could hop to that universe, then hop back to our, and in doing so, you will have travelled backwards in time. Of course, we have get past that whole ERP Bridge science, first!

Answer 7

Go to:

http://en.wikipedia.org/wiki/Time_travel

Answer 8

if time travel was possible, why has the future not come to visit us now?

Answer 9

See, I told you so!