Originally Posted by edgeprod

Don't confuse "infinite" with "has no end". All an "infinite" universe means is that there is no point in the universe that you can go three feet to the left, and physics will work differently. It's more of a shape thing than a size thing. The universe is flat, and without defined boundaries. Other universes "outside" of the context of ours are in differently defined space, but coexist side-by-side (and, in fact, it's theorized that collisions between these universes caused the birth of ours). An infinitely-large universe would preclude this, so clearly it isn't a definitely of space as we think about it normally.