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ost_uid0]Well, if you travel ten minutes back in time, and then just wait out those ten minutes in a dark corner untill you see yourself travel back in time, (this would be like Harry Potter 3), you'd actually be adding mass to the total 4-axis spacetime-continuüm (4 dimensions, width, height, depth and time).
If you weigh 75kg, you'd add 75kg to ten minutes ago, but that'd only last for 10 minutes, because then the first you travels back in time. :smile: So that would add a total of 45000 KgSeconds to the spacetime-continuüm. (I'm not sure if that unit exists, theoratically, but it would in temporal mechanics
) You wouldn't be taking mass away from your current time. This would even work if you go back a 100 years. You die, decompose, and your mass stays in the universe.
On the other hand, if you go back in time, like a 100 years, and go back later it depends. If the time you would go back to travels forward like the time you spend in the past, it'd be like PHJ said. You'd take mass away from your time, and add mass to the past, but the total mass of the spacetime-continuüm would stay the same. But if you travel back a 100 years, then travel back to the exact moment you originally left, you'd again add mass to the total spacetime-continuüm, like in the 10-minutes-example.[/color
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