IMSN

When trying to explain the mechanics of Differential Expansion visual simulations are a good idea. It may give you a better understanding of how it works. Here the differential gravity is shown as a wave from the centre of masses, as the wavefront expands, and reaches another mass, it starts to influence the movement of the masses. Remember the expansion of space is everywhere, from every point, but that would be graphically intense. this simulation shows the differential of expansion caused by the mass.