Astronomers have detected the deepest note ever generated in the cosmos, a B-flat flying through space like a ripple on an invisible pond. No human will actually hear the note, because it is 57 octaves below the keys in the middle of a piano.

The sound waves appear to be heating gas in the Perseus galaxy cluster, some 250 million light-years away.

Other studies have shown that the riotous activity around black holes where gas is accelerated to nearly light-speed produces many notes that are, all together, much like music. Collectively, the cosmos produce, scientists believe, a cacophonic symphony of inaudible tunes.