Lecture 11: The Kerr Black Hole

In Lecture 11, we discussed the charged Kerr black hole. This is the most general stationary black hole solution. The metric for the Kerr black hole is messier to deal with, but we examined the near-horizon geometry and worked out the coordinate transformations that allowed us to cross the horizon in a smooth coordinate system. The interesting new feature that appeared here, was the presence of the ergosphere. In this region, which is outside the horizon except at two points where it touches it, the vector (d/dt) becomes spacelike. This also allows the Penrose process--where, a cleverly designed process can actually extract energy from the black hole.

Lecture 11 notes.pdf