In 1619, Johannes Kepler published his magnum opus Harmonices mundi in which the astronomer derived distinct pitches and scales for each known planet in the solar system from calculations of various aspects of their orbital motions. This was the first theoretical realization of the ancient tradition of musica universalis (also called musica mundana), or music of the celestial bodies. It was not until the Estonian composer Urmas Sisask (b. 1960) began his compositional career by deriving his own “planetary scale,” however, that the theoretical musica universalis came into audible existence. Sisask’s work represents a distinctive musical voice among today’s choral composers, and although he is steadily gaining attention for his unique comp...