The question of what the universe is expanding into seems to come up all the time and the answer is always the same--here's an example from one of the many FAQs around the internet on the subject that all say the same thing: In other words, the universe isn't expanding into anything because it is everything. And that's ok. But I don't understand how that's reconciled with inflationary cosmology, which if I haven't misunderstood anything predicts that our visible universe is most certainly not "everything" and is in fact only a tiny piece of a tiny bubble/pocket (of which there are unimaginable numbers) in a much larger (probably infinite) Universe. So the expansion of the visible universe is a local characteristic of our particular bubble--in fact, there's even an article at space.com today in which Mario Livio discusses the possibility that the value of dark energy varies from pocket universe to pocket universe (and I assume he's talking about the type of pockets that arise in inflation). Is that last bit correct? That the expansion we observe regards only our little piece of the Universe and not the entire Universe itself? Anyway, my main question: if the expansion of spacetime is just the expansion of the tiny amount inside our little bubble of Universe then isn't the generic "the universe isn't expanding into anything because it is everything" flat out incorrect? Isn't the expansion of the universe then similar to a bubble in my can of Sprite expanding (in that there clearly is an outside of the bubble to expand into)? Or am I missing something? I guess I just don't know how the accelerating expansion of "the universe" meshes with the superuniverse that inflation seems to say we're in.