I was thinking of this, a bit. If there is more than one universe, and if (which does not have to follow on all cases) there are "larger" and "smaller" universes, and the smaller are parts of the always invisible level of the microcosm of the larger one (by which i mean that you cannot break up matter enough if you are in the larger universe, so as to reach the outer part of the smaller universe), then wouldn't there have to be, at least in some cases, a specific (maybe even constant, or analogous) ratio of the size of the "parent" universe to the immediately smaller universes contained within it but not reachable from it?
I mean some ratio such as 1 to a trillion trillion trillion etc (just to give an example).
In some cases this won't have to be so (and i suspect in almost all of them). In some cases though, it could.
What do you think of this? Do note that the universes in this model do not have to expand infinitely. They can even have a circular/spheric relation to the smaller and smallest ones, and so just co-exist without expanding. Same goes for the overall 'mass' (it will be another way to view mass, obviously) of each universe in relation to its "density" or some similar quality, they can all be 'equal' in that too.