Roy Kerr discovered the Kerr metric for rotating black holes in 1963.
Kerr, a New Zealand mathematician, found an exact solution to Einstein’s field equations describing the spacetime around a rotating, uncharged mass. His result was published in the paper “Gravitational Field of a Spinning Mass as an Example of Algebraically Special Metrics.” It became one of the central mathematical descriptions of astrophysical black holes.
The metric was important because earlier solutions, such as the Schwarzschild metric, described non-rotating objects. Real astronomical bodies almost always rotate, so Kerr’s solution introduced frame dragging: rotating mass twists nearby spacetime. A rotating black hole also has an ergosphere outside its event horizon, where no observer can remain stationary relative to distant space.
A common mix-up is crediting John Wheeler, Kip Thorne, or Roger Penrose. They made major contributions to black-hole theory, but the 1963 rotating solution is specifically Kerr’s work. In 1965, Kerr and Alfred Schild helped develop the Kerr–Newman solution for rotating, electrically charged black holes.