The event horizon’s size depends on the black hole’s mass and spin, affecting its shape and properties.

A non-rotating black hole has a spherical event horizon defined by its Schwarzschild radius. However, rotating black holes, or Kerr black holes, have distorted, oblate event horizons due to their spin. The rotation drags spacetime around with it, altering the shape and size of the horizon and influencing nearby matter’s behavior. This spin can even affect how matter spirals into the black hole and the energy emitted from the vicinity of the event horizon.