"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.
There were a few famous 19th-century musicians who were seemingly in competitition for the title of "most long-winded composer." When it comes to orchestral music, for example, it's a tossup between Gustav Mahler and Anton Bruckner, who both wrote single symphonies lasting well over an hour.
With opera, though, there's one composer who has the field all to himself: Richard Wagner. His operas Die Meistersinger and Parsifal are both among the longest of all time. But those two are pipsqueaks when compared to his epic, The Ring of the Nibelungen -- a cycle lasting some 15 hours in all.
It's true that Wagner's Ring is actually four dramas, not just one. But together, they tell a single, continuous story -- in a form Wagner called "music drama." And that one story takes four evenings to perform.
Still, the individual works of the Ring do stand quite nicely on their own, and the opening drama, Das Rheingold, is actually one of the most concise operas Wagner ever composed. At about two and a half hours, it's easily the shortest drama in the cycle -- and it can seem even shorter than it really is. Das Rheingold is a 150-minute spectacle that flies by in a flash, introducing vivid new worlds where gods, giants and dwarves all vie for ultimate power. But while the story is surely compelling, the whole thing does take place in just one act -- with no intermissions. So, if you plan on listening to it all in one go, you might think about packing a lunch.
On World of Opera, host Lisa Simeone presents Das Rheingold -- which the composer called the "Preliminary Evening" of his Ring cycle -- from the Royal Opera House, Covent Garden, in London. The stars are bass-baritone Bryn Terfel and baritone Wolfgang Koch as the god Wotan and the Nibelung Alberich, whose vengeful anger sets the entire story of the Ring in motion, in a production led by conductor Antonio Pappano.
When Jacques Offenbach began writing The Tales of Hoffmann, in 1877, he hoped the opera would boost his reputation to a whole new level. It did exactly that -- but unfortunately, the composer never lived to see it.
During his lifetime, Offenbach became world famous as the composer of operettas -- often lightweight comedies, boasting scores of catchy tunes that have often outlived the works they were written for. The prime example is the ubiquitous "Can-Can" from his operetta Orpheus in the Underworld -- a number that tosses out three or four instantly recognizable melodies, all within the space of about ninety seconds.
Still, despite his fame, Offenbach wanted to be known for more than just his frothy operettas, and hoped The Tales of Hoffmann would establish him as a recognized master of serious opera.
The drama is based on a play by the writers Jules Barbier, who wrote the opera's libretto, and Michel Carré. The play takes the real life German poet, E.T.A. Hoffmann, and makes him a character in some of his own, fanciful stories. Offenbach's drama follows the same scheme, placing the title character into three stories of failed love. The result is one of the grandest and most expressive of all 19th-century French operas -- achieving a combination of emotional depth and musical brilliance that only the finest opera composers ever equaled.
The Tales of Hoffmann was scheduled for a premiere at a Paris theater called the Gaite-Lyrique, during its 1877-78 season. When that theater suffered budget cutbacks, Offenbach continued work on the opera -- now intended for another venue, the Opera-Comique. But Offenbach died in 1880, while the premiere production was still in rehearsal, leaving the score incomplete.
Over the years, all the way to the 1980s, scholars continued to find manuscripts for the opera that were left behind, and many different versions of the score have been assembled. But despite those difficulties, The Tales of Hoffmann has long been one of the most popular operas in the standard repertory.
On World of Opera, host Lisa Simeone presents Offenbach's magnum opus in a production from the Grand Liceu Theatre in Barcelona. The title character is played by tenor Michael Spyyres. Hoffmann's three loves are sung by three different sopranos -- Kathleen Kim, Tatiana Pavlovskaya and Natalie Dessay -- while the multiple villain roles are all sung by bass-baritone Laurent Naouri.
What do Jules Massenet, Madonna, Giacomo Puccini and Cyndi Lauper all have in common? As it happens, they all came up with music portraying women who know exactly what they want, and who aren't shy about admitting it.
Cyndi Lauper had a hit in 1983 with "Girls Just Want to Have Fun." Madonna expressed a similar sentiment two years later in "Material Girl" -- which includes the unabashed lyric, "'cause the boy with the cold hard cash is always Mr. Right."
As for Puccini and Massenet, they both wrote operas about a fictional material girl named Manon Lescaut. She had similar requirements for Mr. Right, and she also had a whole lot of fun -- at least for a while.
Actually, it was a fellow named Antoine-Francois Prevost d'Exile -- more commonly known as the Abbé Prévost -- who got it all started. He was an author, and in the 1700s he wrote a sensational, multi-volume series of novels. The last of them was Manon Lescaut -- the story of a willful young woman torn between true love and a life of luxury, and seemingly determined to have both. The book did so well that Massenet, Puccini and a third composer, Daniel Auber, all set it to music in the 19th century.
Auber's version appeared first, in 1856, and has all but disappeared. Massenet and Puccini came up with their Manon operas in 1884 and 1893, respectively. They were both smash hits pretty much right from the start, and have stayed in the repertory ever since.
In Puccini's Manon Lescaut, as in many of his operas, the female lead comes to a bad end. Back in the Abbé Prévost's day, and in Puccini's, as well, people might well have figured that Manon got exactly what she deserved. After all, she did take up with two very different guys, getting just what she wanted from each of them, while refusing to "commit" to either one; they both wanted exclusive relationships, and she told them to forget it. In the opera -- and the novel -- society punishes Manon for her brazen behavior. She's arrested for theft and prostitution, convicted, imprisoned and then exiled.
Today, audiences may not be quite so quick to dismiss Manon as a woman of loose morals. In fact, she could easily be seen as a sort of forward-thinking, iron-willed heroine -- a woman who straightforwardly set about getting what she wanted, using all the resources at her disposal. So, who was Manon? Feminist, or Floozy? We'll reserve judgment -- and urge you to check out the opera and decide for yourself.
On this week's edition of World of Opera, host Lisa Simeone brings us Puccini's Manon Lescaut in a production from the Royal Theater of the Mint, in Brussels, and the Belgian National Opera -- both of which are better known simply as La Monnaie. Eva-Maria Westbroek, one of today's most exciting sopranos, stars in the title role.

For creative artists, there's no single path to recognition. Some achieve it, if at all, only after years of modest triumphs. In contrast, others manage something most can only dream of: a single effort so remarkable that it sets an entire career in motion.