Kepler’s Musical Mathematics
In Harmonices Mundi (1619), astronomer Johannes Kepler wrote musical notations for planetary songs. These celestial harmonies were based on Pythagora’s idea that planets move to a numerical scheme, creating a ‘harmony of the spheres’. Each planet’s speed produces its musical frequency or tone. Together, they make up a chord.
"Kepler scored a part for each of the planets known to him—Saturn, Jupiter, Mars, Earth, Venus, and Mercury—by calculating the high and low notes corresponding to their elliptical orbits. He also included the moon in his chorus: ‘Hicloeum habet etuam’ (Here the moon too has a part). Earth’s orbit is almost circular—only very slightly elliptical—so Kepler declared that its perihelion and aphelion are only one note apart, mi and fa in the medieval scale. Kepler thought this sound was a sad sound, like a moan, and a reminder of the corruption and imperfection of Earth, because of the symbolic association of the notes with misery and famine.” —Lynn Gamwell in Exploring the Invisible
At Bell Laboratories, experimental sound artist Laurie Spiegel composed “Music of the Spheres,” a version of Kepler’s song that was included on the Voyager Golden Record sent into space by NASA. Listen to a 37-second clip here.