Most celestial bodies—from stars and nebulae to quasars and galaxies—emitting light at a wide range of wavelengths. Some include visible light, which is how astronomers can image them with space telescopes like Hubble. But James Webb . Space Telescope and the Chandra X-ray Observatory, which observes celestial objects at infrared and X-ray wavelengths invisible to the human eye. That data is often translated into visible colors to produce breathtaking space images. Now, a team of astronomers is making those images accessible to a wider audience, including the visually impaired—by turning the data into sequences of quasi-musical sounds.
Kim Arcand, a visual scientist who collaborates with a small, independent team of astronomers and musicians on an art and science project called Kim Arcand, says: “If you just create out an image of a Chandra image or another NASA image, you can leave everyone behind. SYSTEM SOUND. Arcand, who describes himself as a former choir and band member, is also the leader of the emerging technology team of NASA’s Chandra observatory. Until a few years ago, this meant activities like adding audio to programs that approached science in virtual reality and augmented reality. Then, along with several others who became the SYSTEM Audio team, Arcand began converting the X-ray data into audio. She said: “We have received such positive feedback from everyone, both sighted and blind or low-vision, that the project continues to work. Today, the team also works with NASA’s Learning Universe, a program that provides science education resources.
visual images from JWST or Chandra instruments are, in a sense, artificial because they use false colors to represent invisible frequencies. (If you really went to places in this deep space, they will look different.) Similarly, Arcand and the SYSTEM Sounds team translate image data at infrared and X-ray wavelengths into sound, rather than into optical color. They call this “supersonication,” and they aim to provide a new way to experience cosmic phenomena, like the birth of stars or the interactions between galaxies.
The translation of 2D images into audio begins with the individual pixels of the image. Each can contain some kind of data—such as X-ray frequencies from Chandra and infrared frequencies from Webb. These can then be mapped onto audio frequencies. Anyone—even a computer program—can do one-to-one conversions between pixels and simple beeps and boops. “But when you’re trying to tell a scientific story about the subject,” says Arcand, “music can help tell that story.”
That’s where Matt Russo, an astrophysicist and musician, comes in. He and his colleagues select a specific image and then feed the data into audio editing software they wrote in Python. (It works a bit like the GarageBand.) Like the cosmic conductor, they have to make musical choices: They choose instruments to represent specific wavelengths (such as an oboe or a flute to represent the pink region. near-infrared or mid-infrared) and choose which instruments objects to capture the listener’s attention in, in what order, and at what speed—similar to moving across a landscape.
They guide the listener through the image by focusing attention on one object at a time or on a selected group so that they can be distinguished from other things in the frame. “You can’t express everything in the picture through the sound,” says Russo. “You have to highlight the most important things.” For example, they can highlight a specific galaxy in a cluster, an arm of an unfolding spiral galaxy, or an exploding bright star. They also tried to distinguish between the foreground and the background of the scene: A bright star in the Milky Way could make cymbals collide, while light from distant galaxies would trigger many lost musical notes. more muted.
