>>12048739travelling backwards in time is not possible.
even when you could go faster then light, you could just observe things before they happen but not interact with the past.
you see your cup of warm chocolate milk falling off your desk. you run with 2x lightspeed to the desk. will you be able to prevent the cup from falling down?
no, because going faster then light will not place the cup back on your desk. it will just change how fast or slow you see it falling. in fact, you would need to run away from your desk to see the cup getting back on the desk. you would have to travel away from the thing you want to observe making it impossible to interact with the past. running towards the thing you want to observe would speed up time for you.
sure, for the people around, you would appear on point b, before you started at point a. for them you would travel back in time. but relative for you it's another story.
let alone the fact of the energy needed and what would happen when you hit other atoms with over lightspeed.
