text: is possible to travel through time??   the answer is simple: we travel through time constantly.  is it possible to travel backwards?  science does not currently know the answer. travelling backwards would entail travel at speeds greater than c (the speed of light).  but it is a fact that to move any body from rest to that speed requires an infinite amount of energy, which does not exist.  so, the only option is to use a particle which always travels faster than c.  this particle is called a tachyon, as predicted by m-theory, but whether or not such a particle exists is currently speculative.  the tachyon has a negative mass, travels at velocities greater than c, and travels in the opposite direction of time as we do.