I hear the universe is infinite, and no matter how far away from earth you go, there’s just infinitely more universe. So like if you are standing on earth looking twelve billion light years that way and then twelve billion light years the other way you are in a sphere of unimaginable size right? But if you actually went twelve billion light years that way once you get there you can still look this way or that way and see twelve billion more light years every which way. So from that perspective, pretty much anywhere in the universe is the center of the universe…from a certain point of view…
Ctrl+F Hitler, ah, there it is. I feel like the xkcd comic missed an opportunity to have a 1932-1945 segment in there about the biggest cause of death for time travelers being OTHER time travelers killing them before they can successfully go back in time and kill Hitler, lol.
Re: conservation of reality, I feel like if I went back and shot Hitler, I would miss, or be stopped by security, or bad weather, or my gun would misfire, or even if I managed to actually do it, he’d be replaced by a look alike, and then it would turn out the guy we always thought was Hitler was actually just an actor, or something. Like if someone went back and killed baby Adolph when he was six months old, the parents would adopt another kid and name IT adolph, and there you go. Whatever happened happened and can’t be undone, not through magic resuscitation of a corpse, but through smooth and natural intervention of reality itself, if that makes sense…