It's referring to the planets, but not the bodies' shape. (Destiny)

by Funkmon , Saturday, September 05, 2015, 22:15 (3464 days ago) @ cheapLEY

Pythagoras and his cult came up with a lot of good stuff and a lot of nutso stuff. One thing they did that was nutso is believe the planets created music in proportion to their orbits. This made more sense then, since they were perceived to travel on spheres, and each orbit was a solid sphere which might have resonant frequencies. The concept is called the Music of the Spheres, referring to the celestial spheres on which the planets travel. They actually thought a bunch of crazy stuff about music, and crazy stuff about space, too. Like they thought the Earth revolved around a central fire with an anti Earth at its other side. Anyway, here's an engraving in Church Latin with info on the orbits, their corresponding Classical muses, and their musical signatures.

THIS is the music of the spheres he is talking about and referencing. It's probably a musical theme written for each of the planets in a corresponding scale.