Sun

In classical physics the future is just a half of the timeline. In special relativity the future is considered as absolute future or the future light cone. In physics, time is considered to be a fourth dimension. Physicists argue that space-time can be understood as a sort of stretchy fabric that can bend due to forces such as gravity. While a person can move backwards or forwards in the three spatial dimensions, many physicists argue you are only able to move forward in time.