According to what I have read, virtual particles are those which are intermediate photons in interactions, which cannot be directly observed. If my understanding is correct that would mean that they consist of (in low order perturbation theory), (among other things) u and t channel photons. But electron electron scattering processes are described by such diagrams. That leads me to believe that all electrostatic coulomb force is mediated by virtual photons. Am i therefore to conclude that coulomb force over observable distance is mediated by photons of sufficiently low frequency so as to be unobservabe? Help would be super. Regards, Gordon.