Ever wondered what the Milky Way might sound like as it rotates on its axis? According to a new “musical expression” by an astronomer, it has distinctly jazz-like tones.
Mark Heyer of the University of Massachusetts Amherst developed an algorithm that expresses the movement of gases in the Milky Way’s disc as musical notes. He’s titled the resulting composition Milky Way Blues.
“This musical expression lets you ‘hear’ the motions of our Milky Way galaxy,” Heyer says. “The notes primarily reflect the velocities of the gas rotating around the centre of our galaxy.”
Using a pentatonic minor scale, he mapped 20 years of radio telescope data on gas in the Milky Way to musical notes and instruments.
The gases that fill the interstellar medium appear in three phases: atomic, molecular and ionised. They also move in certain directions – either towards us or away from us.
Based on their spectra, the gas phases were translated into musical instruments – woodblocks and piano for molecular gas, acoustic bass for atomic gas and saxophone for ionised gas.
High notes indicate gas that is moving towards us, and low notes are for gas that is moving away. Longer notes indicate a stronger emission line.
“Each observation is represented by a line showing where the telescope was pointing and the positions of the circles along a line show the locations of the gas in the galaxy responsible for the played notes,” Heyer explains.
Turning astronomical data into music isn’t a new idea. In fact, “music of the spheres” has been a philosophical concept for millennia – the idea that the movements of the celestial bodies can be considered a kind of music, although in practice it is more of a harmony than actual music.
Johannes Kepler wrote The Harmony of the World in 1619 based on this concept, describing the planets as musical notes based on their orbital velocities.
More recently, astronomers have enjoyed translating their data as actual musical scores.
In 2014, Domenico Vicinanza, a project manager with European high-speed data network Géant, used 36 years’ worth of cosmic ray detections by the Voyager probes to create a musical duet.
And in 2015, Burak Ulaş, an astronomer at the Izmir Turk College Planetarium in Turkey, released a piece he had composed based on the vibrations of the star Y Cam A.
And check this out. Photonic data from a Fermi gamma-ray burst, the most powerful explosions in the Universe, converted into musical notes:
Heyer’s composition is currently featured on Astronomy Sound of the Month, a new website which features projects like these.
There, you can also hear other sounds from space, put together by astronomer Greg Salvesen of the University of California, who designed the visual element for Heyer’s composition.
“You can just enjoy my compositions for the music, but if you want to follow the astronomy, that is there for you to learn about, too,” Heyer said.
“It’s just a cool and different way to appreciate the two together.”