When scientists talk about time travel they don't talk about “time machines” as such, rather the ideas and principals that make time travel possible. In this documentary we hear some radical ideas about time travel from leading scientists from around the world such as Stephen Hawking and Micheo Kayku who believe that it may be possible in the form of a wormhole.
Time is not something that is a constant Einstein proved that, but we know that in our Universe it moves in one direction: Forward. So the idea that we could move through the fourth dimension as we quite easily do in three dimensions opens up an extremely strange world, perhaps something that humans should be doing in the near future as we are now considered to be rated 0.73 / 5 on the kardashev scale. Five being god.