Ok, I knew if I just let it ferment for a while I would come up with something more to say.
Assume that our universe is a bubble of low density in a much larger universe which has a much higher density. Just for grins lets call that the bigverse. Then, since there is much less mass in the universe than in the bigverse there will be a reduced attraction on the side of the bigverse that bounds the universe. That means that the matter at that contact point will be more strongly attracted away from the universe. So then matter in the bigverse will start to clump up. And, as we have seen in the universe that means that the bigverse will start forming the equivalents of stars and galaxies. So that the bigverse will no longer have anything like a consistent density. So most of it will consist of low density areas and there won't be any bubbles such as our universe. Most of the bigverse will consist of a gigantic collection of low density regions with galaxies scattered through it.
Bill Gill
