"The squares of the periodic times are to each other as the cubes of the mean distances."
That's the formula now known as Kepler's third law of planetary motion, the last in a set of formulas that helped form the basis of modern planetary science -- principles established by the groundbreaking mathematician and astronomer Johannes Kepler, in the early decades of the 17th century.
At first glance, Kepler's laws may not seem particularly musical. Yet his thinking was rooted in the ancient concept of "the music of the spheres," and that third law played a major role in one of Kepler's most important works: the 1619 treatise Harmonices Mundi, or The Harmony of the World. And, while Kepler may not have had actual music foremost in his mind when he discussed the world's harmonies, his book has inspired a pair of striking, modern day operas.
The first was by the German composer Paul Hindemith. It was his 1957 opera Die Harmonie der Welt, featuring music that was also adapted as a large symphony.
The second appeared more than 50 years later, when Philip Glass's opera Kepler was first performed in Linz, Austria -- a city where Kepler himself worked for more than a dozen years.
Johannes Kepler was born near Stuttgart in 1571, and died in Regensburg in 1630. He's probably most famous for his laws of planetary motion, but he also made a number of other contributions to the 17th century's scientific revolution -- the period often considered as the birth of modern science.
Kepler contributed to optical science, creating formulas for eyeglasses to correct poor vision, and explaining the principles of the telescope. His discoveries led to the field of astrometry, which measures the distances between heavenly bodies, and his book Stereometrica Doliorum was the basis of integral calculus.
But Kepler's work dealt with more than just abstract science. The fields of astronomy and astrology were interconnected back then, and Kepler tried to relate the astrological "tones" of heavenly bodies to the fate of human souls. A devout Lutheran, he also pondered the relationship of God to the physical world, seeking to discover an overall plan that determines the nature of the universe.
In Philip Glass's opera, it's the breadth and influence of Kepler's thinking that dominates, rather than the details of his life story. So instead of portraying a specific narrative, the opera unfolds in a series of dramatic scenes, evoking the concepts and discoveries that led Kepler from one idea to the next.
On World of Opera,, host Lisa Simeone presents the American premiere production of Glass's Kepler -- and the world premiere of its English language version -- from the 2012 Spoleto Festival USA. Baritone John Hancock stars in the title role, with conductor John Kennedy leading the Westminster Choir and the Spoleto Festival USA Orchestra.