Maybe it's expanding into places where there are spaces between universes (voids). If universes are spheres, there are naturally going to be some voids, as the other, nearby universes can't touch every surface of the sphere. And, maybe the other universes are contracting or expanding in relation to the movement of our own universe.
But how can you explain red shifting( the universe expanding rapidly)
Maybe it's expanding into places where there are spaces between universes (voids). If universes are spheres, there are naturally going to be some voids, as the other, nearby universes can't touch every surface of the sphere. And, maybe the other universes are contracting or expanding in relation to the movement of our own universe.