Can you move forward and backward in spacetime...whatever that is?
What I don't understand about sci-fi stories, is that the Earth rotates and orbits the Sun, etc., so if someone moves in time they won't necessarily be on Earth anymore. So if someone invented a time machine and moved a person into the past or future, they may very well reappear in empty outer space.
I’d love to go back in time to take care of certain things. But then, every experience, every action, every idea, everything that has ever happened in my life has made me the person I am today, living the life I do today. The same for you and everything in your life.
“If you can move forward and backward in space, why can’t you in time?”
Here is a fascinating article by Cosmologist Paul Davies about time.
Excerpts from That Mysterious Flow by Paul Davies:
To be perfectly honest, neither scientists or philosophers really know what time is or why it exists.
Our senses tell us that time flows: namely, that the past is fixed, the future undetermined, and reality lived in the present. Yet various physical and philosophical arguments suggest otherwise.
The passage of time is probably an illusion. Consciousness may involve thermodynamic or quantum processes that lend the impression of living moment by moment.
Time is an extra dimension akin (but not identical) to space. Mathematically, (time) is a one-dimensional space, usually assumed to be continuous, although it may be quantized into discrete chronons, like frames of a movie.