Post-doc astrophysicist Greg Salvesen creates music out of astronomy data, making outer space more accessible to the blind and more engaging for non-scientists.
Astrosom, short for Astronomy Sound of the Month, is a website created by Salvesen that incorporates astronomy data into computerized music compositions. By mapping the phases of gas (molecular, atomic, and ionized) to instruments (piano, acoustic bass, saxophone, and woodblocks), and aligning the velocities of these gases to different pitches of a minor pentatonic blues scale, Salvesen created an astronomical ensemble. New music is added monthly.
Salvesen’s inspiration for Astrosom came from his time in graduate school in the athletic social culture of Boulder, Colorado while he ran with blind and visually impaired athletes. Noticing how astronomy creates barriers to entry due to its predominantly visual domain, he began tinkering with ways to make astronomy more accessible to visually impaired people.
Salvesen is a National Science Foundation astronomy and astrophysics postdoctoral fellow at UCSB. His Astrosom project was initially started to satisfy his service work requirement for the fellowship but eventually became much more.
The Astrosom website is minimalistic and easy to navigate, an intentional choice by Salvesen to make the site compatible with screen reader software, which blind people commonly use to browse the web. The site even has its own built-in screen reader function for the descriptions of the projects.
The web page presents simple, concise material, but according to Salvesen, the underlying code is often very complex. Created in January 2018, the site currently features five projects, each of which took a considerable amount of time and effort to complete.
“Most of what I’m doing is Googling stuff. I’m figuring it out as I go,” said Salvesen in an interview with The Bottom Line.
Each project has distinct aims and varying aesthetics, using different types of interstellar media. Some are more interactive than others, incorporating mouse movements into the sonification process, while others are animations paired with sounds. Some incorporate blues riffs that sonify data of observed gas velocities in our galaxy (such as his “Milky Way Blues”), while others display sounds found from deep space (such as his “The Sound of a Fast Radio Burst”).
Salvesen’s first Astrosom release in January features a picture of deep space taken by the Hubble Space Telescope that contains over 10,000 galaxies, allowing the user to sonify each galaxy by hovering over them with the mouse. The data of each galaxy is mapped to piano notes according to distance. The farthest galaxies, over 13 billion light years away, sound the lowest notes of the piano while the nearest galaxies and stars sound the highest. Interacting with the animation feels like having a conversation with the galaxies.
Astronomers estimate that there are over 2 trillion galaxies in the observable universe. If you were to hold a grain of sand up to the sky at arm’s distance, that’s about how large the patch of sky in Astrosom’s January image was. That image displayed over 10,000 galaxies.
Salvesen’s first memory of hearing music paired with astrophysics data first came from Andy Fabian, a famous astrophysicist, who identified that the note emanating from the supermassive black hole at the center of the Perseus Cluster was a B flat 57 octaves below middle C. According to Salvesen, sonification of astronomical data is a growing field with many calls for this type of work in recent years.
“Never a Mundane Supernova in the Sky,” Astrosom’s February special, illuminates recent advances in imaging technology by mapping all of the observed supernovae over the last 67 years to a xylophone that plays the song “Champagne Supernova” by Oasis.
Each note of the song measures half of a year, and the animation plays one hit of the xylophone per supernova for the full seven minutes of the song. In 1950, an average of 11 supernovae per year were observed for the entire universe. This number leapt to over 6,000 observed supernovae per year by 2017.
Salvesen’s creative process is much akin to an architect who creates an acoustic structure that is then populated by other musicians. “With the astronomy data, I make a set of rules, I map [any given] aspect of the data set to sound following these rules … I set it all up, write a computer code to do it, and out pops … whatever!” Salvesen said.