  Using the result obtained in a prevoius paper, in which I found an upper
limit on the region of particle creation in the vicinity of the event horizon
of a Schwarzschild black hole, and by assuming that all the created energy will
be absorbed by the black hole, a natural power law for the growth of the event
horizon is deduced. This result may explain the existence of galactic black
holes with very large masses. Application of this result on cosmological scale
shows that if we start with a Planck-sized black hole then the natural growth
of such a black hole will produce one with a density equals the present
critical density of the universe. Such a black hole universe will be in the
state of eternal inflation.
