> The boundaries of the universe are the light cone of the big bang. That "boundary" is not a spacial boundary, but simply the farthest distance we can "see".

> The boundaries of the universe are the light cone of the big bang. That "boundary" is not a spacial boundary, but simply the farthest distance we can "see". The universe is expanding fast enough that any given space-time point can only "see" a finite region of the greater universe. But it is all connected. We can see objects far away, whose citizens (if they exist) can see beyond our visible boundary, and so on. And our area is not expanding "into" other areas. Think of the expansion as equally inflating every area, including our own. Pushing distant areas to be more distant. All in a smooth way across the region of the universe we can see and beyond.