I'll assume a perfect sphere under no other influence. What is the exact centre doing? It must be rotating because the rest of the sphere is doing so, and in a measureable way.
I'd think the exact center point is with a high probability empty, so it wouldn't be doing anything. If there happens to be an electron or a muon or whatever other weird crap, idk.
Our brains have just one scale, and we resize our experiences to fit.