The Kerr metric describes space-time around a spherical mass M which has an angular momentum J (such as a rotating black hole). According to the Kerr metric, rotating bodies exhibit frame dragging, which "predicts that objects coming close to a rotating mass will be entrained to participate in its rotation, not because of any applied force or torque that can be felt, but rather because of the curvature of spacetime associated with rotating bodies" (from Wikipedia).

This is a relatively good link to explain the Kerr solution: http://www.statemaster.com/encyclopedia/Kerr-solution

In my opinion a white hole can't exist. I mean, if it's the opposite of a black hole, and releasing a massive amount of mass/matter, then surely that matter would then collapse on itself, and form a black hole...which is ironic if you think about it. So in that respect, worm holes can't exist either since you need a point of entry, and a point of exit...and who decides which is which? And as mentioned earlier, how can a white hole exist if by principle the matter coming out of it would most probably bind, increase in mass...and end up being a black hole?

I'm not too clued up about these things, but to my knowledge the Kerr Black hole is the theory of the black hole having a center which consists of the planet which it originated from...almost like a pit in a fruit...just much smaller in comparison. Thus, everything being sucked in, would then "hit" that center, and either form part of it, increase it's mass and so too the gravity of the black hole...but I might be wrong. The rest is well...above my pay-grade.