idea
Harmony of the spheres
The idea that the sky is a kind of music goes back to the Pythagoreans in ancient Greece. In 1619 Johannes Kepler published Harmonices Mundi, where he showed that for each planet, the ratio between its fastest and slowest speed around the Sun is close to a musical interval: about a major third for Saturn and a fifth for Mars. Today astronomers find simple ratios in real orbits, called orbital resonances, and they study stars by measuring how they vibrate, a little like listening to a bell.