The Laser Interferometer Gravitational-Wave Observatory (LIGO) has discovered ripples in spacetime created by merging black holes. About 1.3 billion years ago two black holes swirled closer and closer together until they crashed in a furious bang. Each black hole packed roughly 30 times the mass of our sun into a minute volume, and their head-on impact came as the two were approaching the speed of light. The staggering strength of the merger gave rise to a new black hole and created a gravitational field so strong that it distorted spacetime in waves that spread throughout space with a power about 50 times stronger than that of all the shining stars and galaxies in the observable universe.