What if time is just a biological clock, you could speed it up or slow it down. To speed it up would require a lot of fuel and it would be costly and you could never reach the speed of light because you have mass and therefore you would never experience the stoppage of time and it is impossible to go faster than the speed of light so you would never travel backwards in time, but you could slow it down dramatically in a time chamber and depending on how long you stay in there when you come out the world would be a very different place.
