  We consider a simple model of the physical vacuum as a self-gravitating
relativistic fluid. Proceeding in a step-by-step manner, we are able to show
that the equations of classical electrodynamics follow if the electromagnetic
four-potential is associated with the four-momentum of a space-filling fluid of
neutral spinors which we identify with neutrinos and antineutrinos. Charged
particles, which we identify with electrons and positrons, act as sinks for the
fluid and have the structure of the maximal fast Kerr solution. Electromagnetic
waves are described by oscillations in the fluid and interactions between
charges occur via the exchange of photons, which have the structure of entwined
neutrino-antineutrino pairs that form twisted closed loops in spacetime
connecting the charges. The model predicts that antimatter has negative mass,
and that neutrinos are matter-antimatter dipoles. Together these suffice to
explain the presence of modified Newtonian dynamics as a gravitational
polarisation effect.
