The most mind boggling paradoxes of all time; the grandfather paradox deals with the repercussions of time travel.
The grandfather paradox is a paradox of time travel in which inconsistencies emerge through changing past.
A person travels back in time to the past and kills their grandfather before the conception of their father or mother, which prevents the time traveler’s existence. HERE LIES THE PARADOX.
The first solution to this famous paradox is that when you go back in time to kill your grandfather, you’re not going back to your own history, but a copy of your history, and everything you do in this version of your history will affect the alternate future of that universe, not your own.
Think about it. All your atoms are scanned and destroyed in the process, because there’s no cloning allowed in quantum mechanics. Then all that information about you is teleported to the new location, where a bunch of new atoms are used to build a whole new you, complete with memories, personality quirks, and that oddly shaped birthmark on your left butt cheek.
Basically, if you go back in time and kill your grandfather, you don’t exist, so your grandfather can’t be killed. So there are two realities happening in parallel here. While all of this is 100 percent hypothetical, because no one’s actually gone back in time to test this out, we do have evidence of two separate realities happening in parallel.