Musica Universalis: Astronomy, Music, and the Liberal Arts

The James Webb Space Telescope Reveals the Universe's Structure

In mid-2022, NASA's James Webb Space Telescope (JWST) released its first images, captivating the world by revealing the cosmos in truly magnificent colors [1].

The first image, transmitted in July of that year, famously displayed a galaxy cluster located in the Southern Hemisphere sky, 5.12 billion light-years away from Earth.

In the words of US President Joe Biden, it was the "deepest and sharpest infrared image of the distant universe to date" [2].

However, NASA was not satisfied with merely revealing these first JWST images visually. For this reason—and remembering the long love story between music and astronomy—scientists attempted to map the colors to different pitches and frequencies.

The result surprised many.

Ancient People Used the Stars as a Musical Template

Music and space, truth be told, might not seem like natural partners. After all, if there is no air, it stands to reason there is no sound. Nevertheless, the connections were obvious to our ancestors.

For example, in ancient Greece, thinkers such as Aristotle believed that Earth was at the center of the universe. However, this did not make it an unchanging ideal: to ancient people, terrestrial phenomena were constantly shifting, which meant our planet was likely "imperfect."

In contrast, the heavens were viewed as unchanging and eternal, and therefore worthy of imitation.

More specifically, some stars moved relative to others—these were "planets" in the etymological sense, as the word planet means "wandering star." At the time, ancient people knew of seven of them: Mercury, Venus, Mars, Jupiter, and Saturn, as well as the Sun and the Moon. This number later dictated the composition of the days of the week, as well as the musical scale [3].

Indeed, to the ancient Greeks, each planet "hung" on a specific sphere, which in turn supposedly rotated around Earth.

Ultimately, given that movement produces sound—for instance, when two objects rub against each other or when feet hit the floor—it made sense to perceive that the spheres moving in space should also emit certain sounds.

Unlike the sounds heard on Earth, these were considered perfect, so ancient people used the stars as a template for celestial music. This is why, in the Middle Ages, astronomy and music were grouped into the quadrivium, alongside arithmetic and geometry, laying the foundations for a liberal arts education.

Musica Universalis: Linking Notes and Planets

Some scholars linked pitch to a planet's distance, while others linked it to its speed. Making these compositions more complex, the understanding of the relative positions of the planets in the solar system varied at the time.

The German astronomer Johannes Kepler was one of the scientists who relied most heavily on this ancient Greek concept of the "music of the spheres." Exploring the musica universalis meaning, Kepler used this framework to help map the planetary system.

Kepler's discoveries catapult us into the modern cosmos: he determined that the Sun is not only at the center of the solar system—as Nicolaus Copernicus had proposed in the previous century—but also that the planets orbit it in an elliptical shape, causing their distance and speed to change along the way.

However, because Kepler believed it was impossible to associate a single note with a single planet, he concluded that the planets emit distinct melodies. In any case, it all had to remain harmonious: for a planet to create a melody, the highest pitch had to sound good—or harmonize—with the lowest.

Eventually, he abandoned this specific theory. Yet, even though the idea of planetary spheres was left behind, the music of the spheres left its mark. Even today, songs and albums continue to be inspired by astronomical concepts, objects, and figures, or alternatively, rely on astronomical data.

For Scientists, the Universe is a Musical Playground

Instead of mapping planetary systems, Kepler's successors now represent the sky through sound, following a few select rules.

More specifically, intense light in an image translates into intense sound: a brighter object creates a louder volume. In turn, the duration of the sound corresponds to the object's appearance. A short musical interlude represents a star, which is essentially a speck in the picture, while a long one represents a hazy cloud.

When discussing pitch, it can directly reflect the frequency of light—a higher pitch for a higher frequency. In this case, the image of a nebula's "mountain" will trigger a ringing rise and fall.

Interestingly, some photos of the galactic center combine both methods: spatial coding with different light frequencies represented by different instruments. For instance, bells are used for X-rays, strings for visible light, and a piano for infrared rays.

And so, although the 17th-century French philosopher Blaise Pascal wrote that "the eternal silence of these infinite spaces" frightened him slightly, for modern scientists, it is a playground of light and, especially, music.