Illustration of gravitational waves emitted by two black holes orbiting each other. Yellow structures near the black holes illustrate the strong curvature of space-time in the region. Orange ripples represent distortions of space-time caused by the rapidly orbiting masses. These distortions spread out and weaken, ultimately becoming gravitational waves (purple). Space-time distortions radiate away orbital energy and cause the pair of black holes to contract, finally merging into a single black hole that settles into its 'ringdown' phase, where the final gravitational waves are emitted.