  Massless neutrino exchange leads to a new long-range force between matter.
Recently, it was claimed both that the potential energy due to this interaction
i) dominates the total energy of neutron stars and ii) that it is zero. We
recalculate the energy of a neutrino propagating in a classical, uniform
background of neutrons and find a negligible, but non-zero contribution to the
total energy of neutron stars. We estimate the neutrino pair creation rate of a
neutron star caused by a density gradient of the background neutrons but found
it too small to be observable.
