In theory, Is time travel possible?

But you would not be able to see Light 1 from You 2 for a "second time" because you would have moved before Light 1 reached You 1 in what would be the first time, surely?

Time travel is pretty simple.


Im doing it now.

i agree with the grandfather paradox, in regards to traveling back in the past. but i can't see what harm would happen if one traveled to the future

I have always been fascinated by the concept of time travel. I wish I could say I believe it were on some level possible, but philosophically I have to doubt it for the following reason;

It is observable that as acceleration increases, time slows at a rate that indicates that at the speed of light its acceleration would be zero. By definition, time would then not exist. One cannot move forward, backward, up or down in that which does not exist.

Of course this only defines acceleration as a means to negate time. Perhaps there is a way to manipulate time other than acceleration. If anybody out there knows of any other theories, I would love to hear them. I would LOVE to believe time travel is possible!

Granted. You actually would be be seeing your past self

Wait a second, the earth isn't flat! I thought Einstein proved the universe is disk shaped and resting on the back of a giant turtle.

Well...if you travel faster than the speed of light...do you visit the future or not? What would Einstein say?

Einstein would say you cant travel faster than light. You cannot even travle as fast as light. But...but, if matter and energy are the same E=MC2, and matter is just condensed energy, then matter converted to energy could travle as fast as light (electromagnetic energy)

If you could travel from London UK to Auckland New Zealand in say 5 hours you would be in the future by almost a day.
Because we in NZ are 24 hours ahead of Greenwich mean time.
This is true, but I'm just kiddin'
I don't believe in time travel in physical nature.
I know there have been experiments with accelorators and in the findings there is a discrepancy in time but I believe there is an interdependancy of time and space.; but this gets a little too much above my understanding of quantum physics...

Theoretically yes time travel is possible.

One guy is making a machine based on one technique now.

But the future doesn't exist yet, so how can it be possible either going back in time or going into the future, plus the concept of time, i.e. like 12'o clock, is a man made concept

Source
The theory of relativity was revolutionary because it showed how the speed at which time happens is mutable; that space and time are not discrete entities: time and space and motion (ie, movement through space) collapse into a fourth dimension, in which all act on each other. It is impossible to say "now" without saying "here" and "how fast".

Or, to put it another way, imagine you have a twin. You stay on earth, your twin goes into space on a fast rocket ship for 10 years; when they come back, they're a couple of years younger than you are. It even works with aeroplanes: circle the earth, flying low; when you return to your starting point, your watch will be slightly behind. "If you were actually moving at the speed of light (which you couldn't do, but suppose you could)," says Penrose, "your watch would stop altogether." It's a rather more expensive method of age-defiance than Cr?me de la Mer, but then again, it has the advantage of being a physical law of the universe.

I'm certain I read that some scientists put an ultra sensitive clock on an aeroplane, when the plane landed (Presumably a long haul flight), they compared this with a clock on earth, and it was found that the aeroplane had travelled in time - albeit by the most fraction of a second.

Course, I might be imagining this.

well i depends on what you define as time travel.
well there was this scientist that did a study on whether gravity affects time. he got two quatum clocks that can measure time to a billionth of a millisecond and put one in his lab and put the other in a fighter jet and asked the pilot to fly round the earth twice as fast as possible.
and when he brought the two clocks back together the one that was in the jet was different to the one in the lab it was ahead by 3 milliseconds.
so when we are higher or lower than our usual gravity time affects us differently, so some scientists beleive that when you spend most of your time in airplanes moving to and from different countries your actually shortening your own life.

If the future is, in theory, already "set," then if we were to time travel, wouldn't it already be predicted that we WOULD time travel?

There's a paradox when it comes to time travel. You go back in time, give someone an object. This someone gives you that object later on in life. Before you go back to give it to him.

This would mean that he got the object from you, but you got it from him. Where did it originally come from?