What is you'r definition of time travel? A person who by some means transports his person to a point in time other than his starting point without living the interviening time period.

A>time travel is a unidirectional trip. going the speed of light or faster will form a time pocket around your ship.time will work normaly to the ships occupants but will seem to accelerate outside the ship.

B> if you go twice the speed of light(not yet possible) for ten years you will move twenty light years away. Then you stop and look back you will see your starting point as it looked ten light years before you left.but you are only seeing a recording of a sort.you could not go back to your starting point instantly so its only a window to the past not door...