What Do The Planets Sound Like?

For a world-renowned composer, Philip Glass is not a very good listener.

On the evening of February 21, Glass joined University of California, Santa Cruz astronomer Greg Laughlin at New York City’s Rubin Museum of Art for a discussion entitled “How Do We Listen to the Music of the Spheres?” — the third event in the Rubin’s 2010 Brainwave series, which provides a forum for communication between scientists and artists.

Downstairs at the Rubin — which houses a collection of Himalayan art — about 100 people gathered in front of a stage furbished with a stylish grand piano, swanky orange lounge chairs, and a large projection screen hooked up to Laughlin’s aluminum MacBook. The evening was an opportunity for two great minds to discover where the orbits of their different disciplines overlap. Although many fascinating ideas were exchanged, Glass often tried to be the sole center of gravity in the room.

Perhaps Glass did not realize how often he interrupted Laughlin only two seconds after asking him a question, claiming that he already knew what Laughlin was about to say (regardless of the audience’s curiosity). Maybe Glass let his excitement get the better of him. But how can Glass announce he’s always loved science and then spend so little time actually learning from the expert scientist sitting right next to him? In fact, the 73-year-old composer proved a very impatient listener, demonstrating an avuncular affinity for rambling narratives, half-formed ideas, and questions of such cosmic proportions that no one could easily or intelligently respond.

Despite the barriers to reciprocal communication, science and art managed to find one another. Admirably, Laughlin was not content to circle Glass like a mere satellite. He made his research a major focus of the evening. And Glass responded with moments of genuine—and even patient—interest and respect, sharing insightful and humorous interpretation of Laughlin’s research.

Laughlin has developed software that translates mathematical models of planetary systems into sounds. Planets orbiting a star cause that star to wobble; Laughlin can plot this wobbling as both equations and audible waveforms. Using Laughlin’s software, one can compare the even tone of a stable planetary system with the wonky vibrato of an unstable one, from which planets will be thrown with great force.

“The ear can sometimes hear what looking at a graph won’t tell you,” Laughlin said. In some ways, it makes more sense to listen for the difference between a stable planetary system and an unstable one than to look for that difference in graphs. Scientists need to predict planetary behavior over many eons — a timescale that is easier to compress as sound than to squeeze into a visual representation.

As one of the most influential composers of the 20^th century — one who has worked on operas about astronomers Galileo Galilei and Johannes Kepler, no less — Glass certainly agreed with Laughlin about the power of sound. But the pensive composer couldn’t keep his mind from indulging in a little philosophical wandering.

“The sound becomes the incident that makes me think about the sound,” Glass said, denying the audience enough elaboration to make complete sense of the statement. “Can we imagine a giant cosmic ear?” Glass asked, wondering if anything like the ‘music of the spheres’ actually exists in the universe and if anyone can hear it. Later on, Laughlin said that “out in space there is no music of the spheres — it’s just a representation of something we create.”

In truth, the sounds Laughlin played for the audience on his Macbook cannot exist on their own. If you fly to space, you won’t hear Earth and Venus engaged in a haunting duet. And yet, all planets in a solar system play together in a kind of orchestra. The planets’ movements follow physical laws, creating patterns in space and time. Scientists can measure and model these patterns: if math is one way to do so, sound is another. Although these sounds require a computer program — a composer — to interpret them, they still correspond to actual interactions between real bodies of mass spinning around one another in space.

The onstage piano inspired many in the audience with the hope of a performance by Glass — but he never touched the instrument. Laughlin also brought musical talent to the Rubin in the form of a Garage Band composition of planetary movements he said he’d composed on the red eye flight to New York City. But Laughlin never got a chance to play his song for us.

Glass may simply have been in too much of a rush to stick around. According to some post-discussion rumor, he left the Rubin almost immediately after the event ended with his stage microphone still attached.