Meteor, no, I haven't heard of sonic black nor white holes. Could you give us a short summary of those two?
Well, let's view white holes as purely theorethical constructs that are possible according to the best theory we have about spacetime. As such, what would be the properties of such a beast?
Would time slow down or speed up near a white hole?
Would a white hole be gravitationally repulsive or attractive?
Where would all this energy come from that the white hole spews out? (Virtual particles materializing because of its repulsive force?) Wouldn't it violate a few rules? Like the simple fact that you can't make something from nothing? (And doesn't the theory which allows white holes take this into account?)
If a black hole consists of too much mass in one place, what would a white hole consist of?
Is there anyone here that thinks quasars could be white holes?