  Massive stellar gravitational collapse is not an endless process. The
Standard Model of particle physics predicts the existence of a repulsive
interaction, two-neutrino mediated, with a coherent weak charge of macroscopic
matter proportional to the number of constituents. After gravity, this is the
second longest range -- microns -- force and, below nanometers, its magnitude
overcomes the attractive gravitation. The layer distribution of pressure inside
a compact neutronized uniform sphere, independent of its size, is compared for
the two interactions with opposite pressure gradient. Taking as reference the
mean square radius, the volume evolution of the pressure, for fixed mass and
weak charge, leads to an equilibrium scenario with a characteristic black-hole
radius $R_B = 1.58$ nm. This size scale should be universal, independent of the
mass, as long as the mass is nearly proportional to the weak charge.
