In 2002, astronomers discovered that the supermassive black hole at the center of the Perseus Galaxy Cluster, which is 250 million light years from earth, sings a single note, detectable only through X-ray observation. The note is a B-flat 57 octaves below middle C, and is estimated to have been constant for approximately 2.5 billion years. The sound may explain a celestial mystery – how galaxy clusters form. Astronomers have long wondered why the gas around galaxy clusters remains so hot instead of cooling and condensing to form trillions of stars. The sound from the black hole may be the answer, providing enough energy for the gas to remain hot and therefore supporting the growth of galaxy clusters, the largest structures in the universe. Black holes don’t just destroy, then; they also help create.