Verified answer

Time Travel into the future is possible. If Free Will exists, then time travel into the past is not possible.

Two Time Machines for travel into the future:

Type 1

Build a space ship capable of near light speed. Put it into a long orbit like a comet that returns to earth every 100 years. Get in the ship and blast off. When you return you will have aged a few years and be 100 years into the earth's future.

Type 2

Build a space station in near orbit to a Black Hole. As long as you are in the space station you age very slowly. When you leave you could be 100s of years in the future.

Special and General Relativity makes either of these possible. The science is solid, the engineering will take some work.

Time Travel into the past:

The possibility of travel to the past hinges on: Does Free Will exist? If we have Free Will then we can change the past and thus the present. The Law of Causality does not allow this. All time travel paradoxes arise from the fact that causality does not allow us to change the present. But, IF everything is fixed and we can’t change it, then some of us, at least, could be time travelers caught in a loop stretching enough years to cover a life time or more maybe 1000s of years. Time Travel need only involve “quantum leaps” that prevent us from meeting ourselves and we live the same lives over and over with no memory of the last time we did it. Something like Joe Haldeman’s “The Accidental Time Machine” would work.

Modern Theoretical Physics offers another way out of the Time Travel to the Past Paradox trap. If there are an infinite number of parallel universes, we can travel back, violate causality and snap to a different universe that results from us changing the past. I.e.: Go ahead and kill your father. You snap to a universe where your father ain’t your father, but your father, he don’t know. Or, maybe he does and he does not care. Or, your mother was raped. Or, .........

See: “Closed Timelike Curves in Asymmetrically Warped Brane Universes,” Pas, Pakvasa, & Weiler

http://science-junkie.group.stumbleupon.com/forum/...

On a basic level sort of and sort of not...

Theories suggest that if you were to travel faster than the speed of light (the fastest 'thing') then theoretically you would be travelling back in time, so hypothetically it is possible. However this would require infinite energy, so physically its highly improbably. SORRY!

I think that if it is possible, then it'll bring about some changes in history that will **** **** up.