I'm not sure that it's so straightforward a situation as that. Since the "one lone particle in the universe" is firmly in Mach effect / Mach principle territory

I'm not sure that it's so straightforward a situation as that. Since the "one lone particle in the universe" is firmly in Mach effect / Mach principle territory. https://en.m.wikipedia.org/wiki/Mach%27s_principle https://en.m.wikipedia.org/wiki/Mach%27s_principle