harmonices mundi

Johannes Kepler - Geometrical Harmonies in the Perfect Solids, “Harmonices Mundi”, 1619.

Kepler was convinced “that the geometrical things have provided the Creator with the model for decorating the whole world”. In Harmony, he attempted to explain the proportions of the natural world - particularly the astronomical and astrological aspects - in terms of music. The central set of “harmonies” was the Musica Universalis or “Music of the Spheres”.

Kepler began by exploring regular polygons and regular solids, including the figures that would come to be known as Kepler’s solids.
Harmony resulted from the tones made by the souls of heavenly bodies - and in the case of astrology, the interaction between those tones and human souls. In the final portion of the work, Kepler dealt with planetary motions, especially relationships between orbital velocity and orbital distance from the Sun. Similar relationships had been used by other astronomers, but Kepler treated them much more precisely and attached new physical significance to them.