  Starting from the Oppenheimer-Snyder solution for gravitational collapse, we
show by putting it into the harmonic coordinates, for which the distant Riemann
metric is galilean, that the final state of collapse for a collapsed star of
any mass, including the one thought to occupy the centre of our galaxy, has a
finite radius roughly equal to its Schwarzschild radius. By applying an
expression for the gravitational energy tensor, we are able to explain the
concentration of stellar material in a thin shell close to the surface, which
gives an explanation for why such a star does not undergo further collapse to a
black hole. The interior of the star is characterized by a low density of the
original stellar material, but, far from being empty, this region is occupied
by a very high density of gravitational energy; this density is negative and
the consequent repulsion is what produces the surface concentration of stellar
material.
