] The voice of a black hole is a deep, deep bass, 57 ] octaves below middle C and far beyond the hearing range ] of humans. The Chandra X-ray Observatory has picked up ] sound waves for the first time from a cluster of galaxies ] 250 million light years away. ] ] Astronomers at the Institute of Astronomy in Cambridge, ] England, discovered the sound waves while analyzing the ] Chandra images of the Perseus cluster, an immense ] grouping of galaxies held in formation by the powerful ] tug of a supermassive black hole. |