Time Travel Paradox Ideas - Except Grandfather

[rootone]

Transporting matter (in human or other form) into the past, increases the total mass-energy content of the past, and decreases the mass energy content of the future.
I think this could get problematic after a few iterations.

 

[BastianQuinn]

Transporting matter (in human or other form) into the past, increases the total mass-energy content of the past, and decreases the mass energy content of the future.
I think this could get problematic after a few iterations.

Wow... I think this might be the only example of a loop which will always close itself. The source of the extra energy is the point in the future, which will have been a universe with the extra mass-energy to spare, because it manifested when it came from the future. If T_p is the moment in the past that the traveling stuff emerges from the future, and T_f is the moment in the future it leaves for the past, then the mass-energy content of the universe at T_p-1 and T_f+1 are equal. There's nothing extra, just folded through space-time. Mass-energy doesn't age or die, and doesn't care if it's "the same stuff". There is no question of where this extra mass-energy comes from or goes, it does not have to stay in the same form, and the equation will always be balanced. This is merely a method of temporarily increasing the mass-energy content of the universe. Similarly, jumping forward in time reduces the mass-energy content temporarily.

I mean, yeah. doing so might be problematic, as you said, but I was surprised to find such a cleanly closed loop in a time travel model.

 

[cpscdave]

In Stephen Baxters Exultant they have FTL drives, and its possible depending on your FTL path to travel back in time. This causes the main character to travel back in time to before he was sent on a doomed mission.
Like many of the other examples listed this results in 2 versions of himself existing.

Later in the book Humans use these FTL loops to create a computer that can solve any problem instantly. It does this by using the time travel loops.
It first checks the time travel result register, if its empty it processes 1 step of the algorithm. If the step produces the answer it sends the result back in time, otherwise it repeats.
One of the engineers remarks that they can build the computer using very cheap components cause they will never actually do any work.
Always thought this was a fun application of time travel :D

 

[Khashishi]

Pool ball is sent into the corner pocket. The corner pocket is the entrance to a time machine. The exit from the time machine is the side pocket...
If the time travel pool ball deflects the original pool away from the pocket, but then enters the pocket itself, you also have a stable reality. Except now you have a loop created entirely by the time travel pool ball.

Maybe this paper is on your mind:
http://journals.aps.org/prd/abstract/10.1103/PhysRevD.44.1077