Is time travel possible?

Answer 1

Einstein's theory of relativity allows for time travel into the future by going near the speed of light. Traveling into the past isn't possible because it creates impossible paradoxes. For example, suppose you could change the past in a way that made sure you were never born (i.e. you killed one of your ancestors). Then you would both exist and not exist at the same "time", an impossible situation. Einstein's theory of relativity doesn't treat time as having both a forward and a backward direction anyway, it just exists and you can travel through it at different "speeds", but always forward.

Answer 2

The possibility that wormholes in General Relativity might act as time machines is still an unresolved issue, though last I heard the general feeling was that quantum gravity would _probably_ prevent this. Since nobody has a definite theory of quantum gravity yet, there's a lot of room for argument over what quantum gravity would or would not prevent. The main issue is that quantum vacuum fluctuations are predicted to occur which are likely to destroy any wormhole which attempts to become a time machine.

There are some theorems in GR which prohibit finite sized time machines without "exotic matter", which is matter with a negative energy density. (Dark energy would also do, in a pinch as far as satisfying the theoretical requirements).

Answer 3

when we consider universe as a space time continuum time depends mostly on the entropy change of the universe. for an entropy in a closing system it is always increasing and cannot be reversed. thats why time travel is not possible.

another probability is that traveling beyond the velocity of light makes time meaningless theoretically. at that situation time travel is somewhat possible but it is an improbability since traveling beyond the velocity of light makes the mass meaningless. thats why time travel is some what impossible.

(good question!)

Answer 4

The calculations of quantum mathematics seem to conclude that time travel to the past may be possible by entering a parallel universe...believe it or not..something similar to that old TV series, "Quantum Leap." However, scientists believe that time travel to the future may be impossible because the future has not yet been determined...for if the future were determined, it would prove the existence of God.

Answer 5

S Hawking once said "If time travel is possible, then where are all the tourists from the future?"

Answer 6

Good question, but no.
To travel to the future, you have to know what will happen. Since we don't, we can't do time travel. Otherwise, knowledge of the future whould prove that God exists.
Time travel would be awesome, though.... :)

Answer 7

Yes, but only into the future, at the rate of 60 minutes per hour.

Answer 8

Reverse time travel is impossible.

Forward leaps have been posited via black hole proximity mechanics or simply by speeds approaching light (i.e. you will age slower than your friends and family).

Answer 9

Any thing is possible. The impossible merely takes longer.

Answer 10

time travelling is IMPOSSIBLE