Originally Posted By: F
Their motion can be taken to be circular in a plane perpendicular to the radius of the universe.


As I visualise this, the galaxy groups could be moving in circles in a wide range of directions, because there is an “infinite” (that's a mathematical infinity smile ) number of directions in which the radius of a spherical universe could lie. However, I suspect that this may not be what you mean, as it is difficult to equate such motion with the type of expansion we observe, and you describe.

There never was nothing.