As far as we know, time only moves in one direction – forward –? but if you could loop back to visit the universe at an earlier point in time, a famous paradox arises.
What if you killed your grandfather when he was a child?
Then your father or mother wouldn't have been born, so you wouldn't have been born, so you wouldn't have been able to go back in time to kill your grandfather in the first place. Paradox.
The simplest resolution to the grandfather paradox is that when you go back in time, you're actually not going back into your own history but to a copy, and everything you do there influences the new alternate future of that universe, not your own past.
But that's boring, because it just avoids the paradox.
If what you do when you go back in time actually influences your own past, and the effects of your time travel do loop back to the present. . . future. . . past– no problem.
Let's just follow the paradoxical timeline through BEYOND its paradoxical conclusion.
You go back in time, kill your grandfather, thus you aren't born so you can't go back in time, thus your grandfather isn't killed, thus you are born, so you go back in time and kill your grandfather, and so on. . .
I'm showing this as a linear series of events but really it's two entangled histories happening in parallel.
Is that even possible?
