Since time is part of the equation for acceleration, and time slows as gravity increases, would this not limit the amount of gravity a black hole could produce? It seems that this would be a kind of negative feedback that would prevent the formation of a black hole out of an accretion disk. What am I missing? Edit: Now, if this were so, we would observe that the outer reaches of galaxies are more effective in producing gravity than the inner reaches of galaxies where the gravitational field is strongest. Such a condition would skew our calculations about the orbital speed of stars as they move in galactic orbit. Stars with extra massive black holes would show the effect more than less massive galaxies.