From looking at it, it appears to be pretty much a typical "overbalanced wheel" type of device (or rather a series of such wheels stacked on the same...
Obviously, if the distance between galaxy clusters is increasing, there must be more "new" space between them, or else the existing space is getting...
I've taught university-level introductory physics labs, and I'm sad to report that very few of the students I worked with had a decent understanding...