Astronomers of the past believed that music and astronomy were intimately related if not outright the same thing. Going back to Nicomachus in his 3rd century work, Manual of Harmonics, this idea has been around in one form or other for a very long time all over the world. The music of the spheres was a very popular concept. Basically, astronomers of past eras believed that the planets "sang" as they orbited. After all, all moving or spinning bodies can produce a tone so why not a spinning planet swinging continuously around the sun?

According to Nicomachus, the Greeks had each planet represented by a musical note. The pitches fell the higher up the celestial ladder one went. The celestial ladder from nearest to farthest was conceived of as Luna, Mercury, Venus, Sol, Mars, Jupiter and Saturn. So Luna had the highest pitch and Saturn the lowest. But shouldn't Saturn be the highest since it is at the top of the ladder? According Nicomachus, the Greeks saw Saturn as being farther from the earth and so if one attached a string from earth to Saturn it would be much longer than the one attached from the earth to Luna. The longer the string, the lower the pitch. This may also explain why Greek scales were descending instead ascending as our modern scales. All the planets together sang in a beautiful harmony. The universe was a symphony.

Sounds like old superstitious garbage? The following is a Reuters news article a few years back:

WASHINGTON, Sept. 9 — Big black holes sing bass. One particularly monstrous black hole has probably been humming B-flat for billions of years, but at a pitch no human could hear, let alone sing, astronomers said Tuesday. "The intensity of the sound is comparable to human speech," said Andrew Fabian of the Institute of Astronomy at Cambridge, England. But the pitch of the sound is about 57 octaves below the middle C at the middle of a standard piano keyboard.

This is far, far deeper than humans can hear, the researchers said, and they believe it is the deepest note ever detected in the universe.

The sound is emanating from the Perseus Cluster, a giant clump of galaxies 250 million light-years from Earth. A light-year is about 6 trillion miles (10 trillion kilometers), the distance light travels in a year.

Fabian and his colleagues used NASA's orbiting Chandra X-Ray Observatory to investigate X-rays coming from the cluster's heart. Researchers presumed that a supermassive black hole, with perhaps 2.5 billion times the mass of our sun, lay there, and the activity around the center bolstered this assumption.