Holes: Black and White

Lubos Motl has a new post up on Black Holes and White. I think that he gets a bit carried away with his theme that white holes are not time reversed black holes, but he makes some illuminating points. From the standpoint of pure general relativity, I think, it really is true that white holes are time reversed black holes - at least from the standpoint of a distant observer. There is one very important experimental fact about white holes: they don't seem to exist.

There is one sort of exception, however: the Big Bang. I asked him about this, and if I correctly understand his answer, it's this: entropy. Black holes have a very large entropy, but the big bang had extremely low entropy. I like this answer a lot, mostly because it takes us back to microphysics. What follows are my own thoughts, inspired by Lumo's comment but hardly his fault.

If we look at a black hole in terms of its interior, or maybe just its surface, as a seething mass of strings (or what have you), only an incredibly unlikely coincidence could correlate the momenta so precisely as to detonate the black hole as a white hole. (Like the shattered watch spontaneously reassembling itself times ten to the zillionth). The white hole at the beginning of time had to be different.

Perhaps that cosmic egg was in some state of very high symmetry such that it could only decay in some very precisely correlated way, such that the momenta really did conspire.