I do not think there is any limit on how far collapse of a black hole can proceed. The real limit is rather on how far you can sensibly use the notions of size or distance at all.
It is not that collapse of a black hole runs up against a point that it can't compress anymore. It is that the collapse runs up against conditions in which the notions of space and time break down altogether.
The major lack in modern physics is a combination of gravity with the three other fundamanental forces. Basically, this will require some combination of quantum physics and relativity. There is no good match up at small scales.
This match up is definitely not going to save all the common day intuitions people bring to the table. We tend to rebel at the notions of unbounded collapse in size; and to a strong bound on durations. In a classical treatment of the black hole, for example, every world line terminates at the singularity. It is not even a case of "stuff" falling into the hole and remaining thereafter in an infinitely compressed state. There is no "thereafter" in the singularity either.
If we do develop a unified physics able to manage all fundamental forces and reconcile relativity and quantum physics at every level, then formal descriptions of the black hole may change. I consider it a fairly safe bet that any such theory will replance the currently unintuitive notions with stuff that is even further removed from our normal experience.
Cheers -- Sylas
This message has been edited by Sylas, 05-16-2005 11:04 PM
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