In 1619, German astronomer Johannes Kepler published his Harmonices Mundi (Harmony of the World), a text that investigated how mathematics could help the planets of the solar system create celestial music based on their orbital resonances. Three hundred years later, an astronomer using discoveries from NASA’s Kepler mission has arranged thousands of exoplanets in their own grand sonata.
As telescopes have become more automated, astronomical data have evolved from a trickle to a roaring river. During its primary and extended missions, Kepler identified nearly 5,000 confirmed and candidate exoplanets. The first candidates came in small doses, allowing astronomers to get to know them well. But later observations came in giant batches that were more challenging to parse.
“There’s too many of them to look at individually,” said Jason Steffen, an astronomer at the University of Nevada, Las Vegas. “Now that there are so many, they are falling through the cracks.”
Steffen, who studied some music theory and said he knows “just enough to be dangerous,” realized that the Kepler worlds could produce scientific insights when set to music. At the same time, he came across a YouTube video claiming that sonification—setting data to sound—doesn’t produce much useful science.
“I took that as a challenge,” Steffen said. “Planetary systems have good insight that can be gained when you sonify the data.”
Steffen produced a YouTube video of the thousands of exoplanets that combines information about their orbits with sound.
The volume of the system is set by its largest planet, with louder chords corresponding to larger worlds. The lowest note is set by the orbital period of the largest world, with a lower note lining up with a longer orbital period.