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 compositional style, only limited information exists about the specifics of his background, his interest in astronomy and shamanism, and the subsequent influence these interests have had on his choral music. At once traditional and modern, he bridges the gap between ancient Estonian folk song and the present. Through an application of exotic techniques including extreme repetition, ritualistically driving rhythms and sudden changes in timbre and texture; coupled with his own peculiarly crafted “planetary scale,” Urmas Sisask has created a completely unique body of work which is examined in this study by looking at representative works from his choral oeuvre including Gloria Patri…24 hymns for mixed choir, Magnificat, Ave Sol, and Benedictio.