  As the mass-energy is universally self-gravitating, the gravitational binding
energy must be subtracted self-consistently from its bare mass value so as to
give the physical gravitational mass. Such a self-consistent gravitational
self-energy correction can be made non-perturbatively by the use of a
gravitational `charging' technique, where we calculate the incremental change
$dm$ of the physical mass of the cosmological object, of size $r_o$ due to the
accretion of a bare mass $dM$, corresponding to the gravitational coupling-in
of the successive zero-point vacuum modes, i.e., of the Casimir energy, whose
bare value $\Sigma_{\bf k} \hbar ck$ is infinite. Integrating the `charging'
equation, $dm = dM - (3\alpha/5)Gm\Delta M/r_o c^2$, we get a gravitational
mass for the cosmological object that remains finite even in the limit of the
infinite zero-point vacuum energy, i.e., without any ultraviolet cut-off
imposed. Here $\alpha$ is a geometrical factor of order unity. Also, setting
$r_o = c/H$, the Hubble length, we get the corresponding cosmological density
parameter $\Omega \simeq 1$, without any adjustable parameter. The cosmological
significance of this finite and unique contribution of the otherwise infinite
zero-point vacuum energy to the density parameter can hardly be overstated.
