At the event horizon for a black hole is R=2GM/C^2 This means that, as a star collapses, it gets more dense until this limit is reached. Assuming a consistent density (just an approximation as I know this will not really be the case), the Mass will reduce proportionally to the cube of R, but the event horizon goes down proportional to M - so the event horizon radius reduces faster than the mass that would create it. This means that, below the event horizon, time is still moving. Assuming the minimum size of a naturally occurring black hole is about 2 stellar masses - this gives us a radius of about 6km inside every black hole where time still moves. Or does the star instantaneously collapse to a singularity? If so, how can it continue to collapse once time has stopped?