Is time travel possible?

Answer 1

Sure. You're traveling forward in time right now, at a rate of 1 second per second.

If we ever develop the technology to move at relativistic speed, you can travel into the future at an accelerated rate. For example, you might spend five years on a starship, then return to Earth to find that a century has passed. The proposed technology of cryogenic sleep will also allow one to travel into the future at an accelerated rate.

However, traveling backwards in time only happens in the movies.

Recommended reading:

Short Story "The Pusher" by John Varley, about a "pusher" (that is, starship crewman) and how he deals with accelerated time travel.

Novel "A World Out Of Time" about a starship crewman who travels deeply into the future to find a drastically altered Earth.

Answer 2

Theoretically, according to Einstein's theory of Relativity and normal Physics, time travel is possible. There is a relation between motion and time. In theory, the faster you go, the slower time becomes for you. When you reach the speed of light, time stops. When you travel faster than light, you begin to go back in time.

Consider this story. Sarah and Sam are twins. Sam stays on earth while Sarah goes off in a spaceship with a velocity nearly equal to that of light, orbits a star and returns in what she thinks was one month. When she come back, Sam will be 5 years older than her.

That is the simple theory of traveling to the future. The practicability of this must be questioned. You can never travel as fast as light. With speed, mass increases a lot. By the time one reaches the speed of light, one's mass would have become infinite.

There is something called the Grandfather paradox. Suppose you travel so much faster than light that you land way back to the past, to the childhood of your Grandfather and kill him before he meets his future wife (your grandma). That would make it impossible for one of your parents to have been born and there would be no you in your grandmother's future. then, there would be no one to travel back in time and kill your grandfather later in your grandmother's future. But here you are, having done the deed. So, since later it implies that you never existed, who travelled back in time? A shadow, a ghost? See how confusing it all becomes?

Theoretically, time travel is possible. Practically, far from so.

Answer 3

time is a relative term ( thanks Albert) it is a variable and can change relative to the observer. it can be speeded up or slowed down (in relation to the observer and their frame of refrence. however the speed of light is like a cosmic speed limit because the closer you approach it the more energy you must use to accelerate untill you need infinite energy to get any closer to it ( anything infinite is highly questionable) therefore you can bend the hell out of time but never bring it to a dead stop (to an outside observer)
If you cant even stop time you certianly cant reverse it.
there are some theories that the speed limit also works in reverse.That a particle moving at greater than the speed of light moves through time backwards and can never slow down enough to join our time line ...these are pretty fringe theories though and unproven
the bottom line is that at the speed of light matter and energy are interchangable and at that instant the participant partical ceases to exist as matter and that pretty much precludes time travel...sorry.......wish i knew then what i know now too
see you on the other side

Answer 4

(PhD Physicist responds) Time travel is possible. You're doing it right now, travelling forward in time at one second per second. On a fast moving spaceship, Lorenz contraction of time would have you return in 5 years while, say, 20 years had passed on earth, so you would have travelled into the future.
Travel into the past, or return to your starting point after travelling into the future? Most scientists believe it is not possible. If you could travel into the past, you could kill your grandfather before your father was born. In which case, you wouldn't be born. In which case, you couldn't go back and kill your grandfather. This is called a PARADOX. Scientists generally believe that paradoxes signal impossibilities. In order to travel back in time, relativity tells us that your mass would have to become imaginary. We know of nothing that will do that. Real dimensions are space-like and imaginary dimensions are time-like. So you'd have to turn space into time, and vice-versa.
Also, if time travel to the past does become possible, why haven't we ever seen travelers from the future here?

Answer 5

You'd have to get past the speed of light, without making the jump into becoming pure energy. If you could do this, you'd actually be traveling at a negative relativistic speed, and therefore, backwards. The problem then becomes how to build enough speed, and how to surpass the speed of light without actually reaching it.

Answer 6

Science makes all impossibles possible. Time has proved many. But 'Time travel' we have to wait and see, may be after generations.

Answer 7

no sorry. As my old physics teacher would say: "if you could go back in time, you wouldn't be here... (meaning in this class) And you would be very rich! So remember me if you ever figure out a way"

Answer 8

Sure, oops, got to run, my time machine is about to depart. I'll talk to you yesterday.

Answer 9

if you have a time machine