1. David exists at time T = 2pm PST August 1, 2021.
2. David travels back in time to before time T.
3. Now there is the original David-O and a "copy" David-C.
4. David-C goes up to David-O and kills him.
5. Therefore, David-O is not alive at time 2pm PST August 1, 2021.
6. Therefore, David-O does not exist at time T.
7. And therefore, David-O does not travel back in time at all.
The Theory of Time Travel leads to a logical contradiction. Therefore, it is a bad and invalid theory.
Proving the Relativistic Energy-Momentum relation, the hard way and the easier way.
This adds the proof for the relativistic mass effects from motion, proving that gravity causes it.
Two reference frames in motions are not symmetrical. A system at rest on the surface of a planet moves faster in time than a moving system. This is not the case using just Special Relativity. This is proven just using the gravitational metric field in General Relativity.
