Polarization of vacuum fluctuations: source of the vacuum permittivity and speed of light

There are two types of fluctuations in the quantum vacuum: type 1 vacuum fluctuations are on shell and can interact with matter in specific, limited ways that have observable consequences; type 2 vacuum fluctuations are off shell and cannot interact with matter. A photon will polarize a type 1, bound, charged lepton-antilepton vacuum fluctuation in much the same manner that it would polarize a dielectric, suggesting the method used here for calculating the permittivity ${ϵ}_0$ of the vacuum. In a model that retains only leading terms, $\epsilon_0 \cong (6\mu_0/\pi)(8e^2/\hbar)^2= 9.10\times 10^{-12}$C\mathrm{/}(Vm)\mathrm{.}Thecalculatedvaluefor$\epsilon_0$ is 2.7% more than the accepted value. The permittivity of the vacuum, in turn, determines the speed $c$ of light in the vacuum. Since the vacuum is at rest with respect to every inertial frame of reference, $c$ is the same in every inertial reference frame.