What Kerr did was to sit down and write some very complex equations which model very accurately what goes on near a black hole. Scientists use Kerr's equations to guess what black holes might do as they pass through space, and science fiction writers ignore Kerr's equations when they make spaceships fly into them and arrive in another dimension. If Arthur C. Clarke had just done his maths, that whole 2001 Space Odyssey thing would never have happened. From the time of Kerr's announcement of his theory, it proved to be enormously useful way of describing what scientists call 'spacetime'. The 'Kerr Metric' (also known as the Kerr Vacuum solution), is still the method used to examine the complex geometry of the region surrounding black holes.