What happens when science puts the universe to music?

Just over six months ago, NASA’s James Webb Space Telescope (JWST) presented its first images, dazzling the world as it revealed the universe in brilliant technical colours. The first image, sent back in July, showed a galaxy cluster in the southern hemisphere sky, 5.12 billion light-years from Earth. In the words of US President Joe Biden, it represented “the deepest and most accurate infrared image of the distant universe” taken by humanity to date.

But NASA didn’t just visually reveal the first JWST images. Drawing on the long love story between music and astronomy, the scientists plotted the colors according to different pitches of sound.

Music and Astronomy: An Ancient Love Story

Music and space may not seem like natural partners – after all, no air means no sound. But the connections were obvious to our ancestors. In ancient Greece, thinkers such as Aristotle believed that the Earth lay at the center of the universe. However, this did not make him a static ideal: for the ancients, terrestrial phenomena were constantly changing, which is a reflection of the imperfection of our planet. By contrast, heaven was seen as immutable and eternal, and thus worthy of emulation.

A few stars moved relative to the others – the so-called “planets” in the etymological sense (for “planet” means “wandering star”). The ancients knew seven of them: Mercury, Venus, Mars, Jupiter and Saturn, in addition to the Sun and Moon. This number will continue to report the composition of the days of the week as well as the musical scale.

Indeed, for the ancient Greeks, each planet was suspended on a sphere, which, in turn, revolved around the Earth. Given that motion from sound here – as when two objects rub against each other or feet hit the ground – it makes sense that moving balls in the universe would also make sounds. Unlike those heard on earth, these were thought to be perfect, which led the ancients to use the stars as a model for earthly music. This is why medieval astronomy and music were grouped together in the quadrangle, which also included arithmetic and geometry, laying the foundations for a liberal arts education.

Draw stars on the musical scale

But how do we weave the observations and planets together? This is the hardest part admittedly. Some scientists associate pitch with the distance of a planet, others with its speed. To add more complexity to the compositions, perceptions at the time differed in the relative positions of the planets in the solar system.

German astronomer Johannes Kepler (1571-1630) was one of the scientists who notably drew on this ancient Greek concept of “music of the spheres” (also known as musica universalis) to map the planetary system.

Kepler’s findings will propel us into the modern universe: He determined that not only was the sun at the center of the solar system—as Nicolaus Copernicus suggested last century—but also that the planets revolved around it in an ellipsoid rather than a circular motion. As a result, the distance and speed of the orbital path changed. It became impossible to associate a single note with a single planet, which led him to conclude that planets sing melodies.

Of course, all of this must remain in harmony: for a planet to produce a melody, the higher one must harmonize well with the lower one. Eventually, Kepler abandoned his tunes to focus on elucidating his third law of planetary motion in 1619.

While we’ve long left the idea of ​​planetesimals behind, Balls Music has left its mark—and even today, songs and albums still bear its name, including Coldplay’s latest work. The relationship between astronomy and music continued to evolve further, with music inspired by astronomical concepts, objects, or people, or alternatively drawing on real astronomical data.

Kepler’s heirs

Instead of mapping planetary systems, Kepler’s heirs are now mapping the sky with sounds, following a few chosen rules. The intense light in the image translates into intense volume: a brighter object produces a louder sound. In turn, the duration of the sound corresponds to the object’s appearance: short for a star (which is essentially a spot in an image), and long for a hazy cloud.

For tone, it can either directly reflect the frequency of the light (a higher pitch if the frequency is higher) or be a spatial notation (the louder the object in the image, the higher the pitch). In this case, the image of the “mountain” nebula will produce a sonorous ascent and descent. In an image of the center of our galaxy released for the Chandra Space Telescope, both methods have been combined: spatial coding with different light frequencies represented by different instruments (bells for X-rays, strings for visible light, and pianos for infrared).

In 1606, the French philosopher Blaise Pascal wrote that the “eternal silence of these infinite expanses” terrified him. However, for modern scholars, they are a playground for light and especially for music.

This article is republished from The Conversation under a Creative Commons license. Read the original article.