The ZPE equates with the 'background' omnipresent ocean of universal energy, whose em vibrational wavelengths exist from the microscopic to the macroscopic. According WSM, all so called matter particles are formed of this energy at points where in out wave standing wave resonance occurs. And btw, the same logic applies to the reason for the spherical form that the macroscopic objects of the universe take....ie.planets , suns, galaxies etc.,...but the incoming outgoing wavelengths in this case are measured in thousands of kilometers to hundreds of thousands of light years