Also time travel is scientifically possible for a specific location. If you gather enough energy and observe every particle in the object you wanna reverse. If you can recall the cells previous state, you can technically re engineer or re develop the cell and its memories using the same energy and making it younger. The flow of time is just an illusion used to describe movement. The faster you move or think, The faster time flows since its only a documentation of the previous state or movement. It would kinda work like your body growing new layers of skin. If you cut yourself you will notice the skin will be fresh and pink a few weeks down the road. If we can take the human body and re construct the cells to a younger state. We would revert the humans age to a previous state. it would cost energy to do so but thats what our sciencey machines are for. This is why we do not recall time flow when unconscious. Since there is no memory to recall, from the time we go to sleep to the time we wake up, we will never fell time pass.