If that's correct (and I have no idea if it is, it just seems logical to me), then even if it were technically possible to, the actual act of sending anything
physically "back in time" would instantly cause that same matter/energy not to exist in its present (future?
) form, and as such, cease to exist completely... Which means the past wouldn't really be affected in any way whatsoever, in the end.
Did any of that make any kind of sense?
While that might make sense logically
, you have to remember that the new areas of physics being explored defy logic. Just read anything related to Quantum Physics, and you'll scratch your scalp off wondering how the hell ANYTHING you read could be possible.
To answer the question: "If you go back, won't that remove the present (future) you from existence?".
Not necessarily. Quantum Physical experiments in teleportation have provided us a reasoning for how it could be possible. Experiments have proved that teleportation of particles IS possible! However, it doesn't disappear and reappear in another place. Rather, lets say you have particle A, B, and C.
You want to teleport particle A to the location of particle C. Experiments have produced the following results:
Particle A was COPIED to particle B, and vice versa. Then the NEW particle B (originally: Particle A) was copied to particle C, and vice versa. Now, they did not merely "change spots". Rather, their "anatomical" configuration was transposed from one to the other. As a result, Particle A had been "teleported" to Particle B.
Quantum Physics has also taught us about particle pairs. Where, no matter how far the distance between them, if one particle changes it's spin
, the other particle changes it's spin correspondingly.
To bring these ideas together, it could be possible (assuming that we had created some sort of apparatus to move into the past), for one to send themselves back. They would, however, be making a copy of themselves in the process. Then any actions this "new" person makes would (through the Butterfly Effect) have an effect on their original, future self.
One other implication is that not only the copy and the future are linked together through Quantum Physics...The copy, the future, and the past-self where the copy was sent; they would have effects on each other. The future self would have no effects on the Past-Self or the copy, yet the opposite WOULD be true, seeing as the reactions (health, environment, etc.) of the future self is dependent upon the actions of the Past-Self and the copy (if it were to interfere in the course of the Past-Self.
Sorry if anyone is too confused