  We present a first-principles' prediction that two charged particles of
masses M_1 and M_2 separated R apart in a dielectric vacuum act on each other
always an attractive force in addition to other known forces in between. This
component attractive force on one charge results as the Lorentz force in the
radiation depolarization- and magnetic- fields of the other charge, being an
attractive radiation force, and is in addition to the ordinary repulsive
radiation force. The exact solution for the attractive radiation force is
F_g=G' M_1M_2/R^2, an identical formula to Newton's law of gravitation.
G'=\chi_{0^*}e^4/4\pi\epsilon_0^2\hbar^2\rho_l is identifiable with Newton's
gravitational constant, \chi_{0^*} being the susceptibility and \rho_l the
linear mass density of the vacuum, and the remaining fundamental constants of
the usual meaning. The F_g force is conveyed by a transverse vacuuonic
dipole-moment wave traveling at the velocity of light and can penetrate matter
freely. In all of respects, the F_g force represents a viable cause of Newton's
universal gravity.
