So I was listening to this Radiolab podcast, an interview with Brian Greene. Apparently, if the universe is indeed infinite, there could be an infinite number of duplicate "Earths" and infinite near-duplicates somewhere out in the universe. If you flip a coin five times in a row, you'll have a certain pattern, like heads-heads-tails-tails-tails. Flip it five more times and you'll probably come up with a different pattern. But flip long enough and eventually you'll have flipped all possible combinations. Then, of course, the next set of five you flip is guaranteed to repeat one of the patterns you've done already. And if you live forever and flip infinitely, you'll flip each possible combination an infinite number of times. Well, the Earth has a finite number of atoms that make it up. An unfathomably large number, of course, but a finite one. So, there are a finite number of ways that this number of atoms can be arranged. A very very very large but finite number. So if you go out into the universe and look for planets, each one is going to be different from Earth in some way, right? Right. But if you go out long enough, you'll have exhausted all possible combinations of the way a planet's atoms can be arranged. Then, see, you'll inevitably find a planet that is an exact duplicate of a planet you've already visited, such as Earth. Keep going and eventually you'll come upon another Earth duplicate, and yet another, and another—remember, we're talking about ∞ here!—and another, and another.... So, yeah, an infinite number of Earth clones. Plus an infinite number of almost-clones, where everything on Earth is exactly the same, but maybe some wine glass on some table in some restaurant is sitting two inches to the left of its counterpart's position on our Earth. So basically, everything in the universe is infinitely duplicated elsewhere in the universe. There are infinite "you"s out there.
As weird as this sounds—and I'd have to say it must be the weirdest thing I've ever heard—what's weirder is that it ACTUALLY MAKES SENSE. I can't stop thinking about it. I can't stop thinking about how out there somewhere, there are an infinite number of Matts typing a sentence identical to this one, on an identical computer, in an identical apartment, in an identical New York, on an identical speck of dust known to its inhabitants as "Earth".