All of a sudden a tiny little bubble will appear. It can appear anywhere—under your chair, or somewhere in Andromeda, very far away—and this little tiny thing starts growing at a speed that’s pretty close to the speed of light. And as it expands, all things that it engulfs turn into an alien form of matter. It may be approaching us right now. Say it nucleated at Andromeda some millions of years ago, it may be expanding toward us at the speed of light. But we don’t get much of a warning. So the good thing about it is you don’t really have to worry about it.
So what would happen to the Earth? It would just go, “FLOOP!” and not exist anymore?
Yeah. Inside of this bubble, ordinary matter as we know it does not exist. It’s made up of different kinds of particles. So everything will be turned into some other stuff that we just don’t know about. But aside from the fact that the end will come very quickly, the other piece of good news is that the probability of the universe ending at any given moment is extremely low.