Astronomers often look at objects in space through multiple telescopes. Because different telescopes can detect different types of light, each brings its own pieces of information to whatever is being observed. This is similar in some ways to how different notes of the musical scale can be played together to create harmonies that are impossible with single notes alone.
In the past few years, NASA has been producing “sonifications” of astronomical data of objects in space. This project takes the digital data captured by its telescopes in space — most of which is invisible to our unaided eyes — and translates them into musical notes and sounds so they can be heard rather than seen. Each layer of sound in these sonifications represents particular wavelengths of light detected by NASA’s Chandra X-ray Observatory, James Webb Space Telescope, Hubble Space Telescope, and Spitzer Space Telescope in various combinations.
R Aquarii (above)
The system called R Aquarii contains two stars — a white dwarf and a red giant — in orbit around each other. In a composite visual image, Hubble data (red and blue) reveal spectacular structures that are evidence of outbursts generated by the pair of stars buried at the center of the image. X-rays from Chandra show a jet from the white dwarf banging into the material surrounding it and creating shock waves. In the sonification of R Aquarii, the piece evolves as a radar-like scan of the image, clockwise starting at the 12 o’clock position. The volume changes in proportion to the brightness of sources in Hubble’s visible light and Chandra’s X-ray image, while the distance from the center dictates the musical pitch (higher notes are farther out). The deep thuds toward the four corners are “diffraction spikes,” which are artifacts from the bright central star. Listeners can hear jets from the white dwarf as the cursor travels near the two o’clock and eight o’clock positions. The ribbon-like arcs captured by Hubble create a rising and falling melody that sounds similar to a set of singing bowls (metal bowls that produce different sounds and tones when struck with a mallet), while the Chandra data are rendered to sound more like a synthetic and windy purr.
In Stephan’s Quintet, four galaxies move around each other, held together by gravity, while a fifth galaxy sits in the frame but is actually at a much different distance. A visual image of Stephan’s Quintet contains infrared light from the James Webb Space Telescope (red, orange, yellow, green, and blue) with additional data from the Spitzer Space Telescope (red, green, and blue) and X-ray light from Chandra (light blue). A sonification of these data begins at the top and scans the image downward. As the cursor moves, the pitch changes in relationship to the brightness in different ways. The background galaxies and foreground stars in the visual images Webb detects are mapped to different notes on a synthetic glass marimba. Meanwhile, stars with diffraction spikes are played as crash cymbals. The galaxies of Stephan’s Quintet themselves are heard as smoothly changing frequencies as the scan passes over them. The X-rays from Chandra, which reveal a shock wave that has superheated gas to tens of millions of degrees, are represented by a synthetic string sound.
Messier 104 (M104 for short), located about 28 million light-years from Earth, is one of the largest galaxies in the nearby Virgo cluster. As seen from Earth, the galaxy is angled nearly edge-on allowing a view of its bright core and spiral arms wrapped around it. Spitzer's infrared view of M104 shows a ring of dust circling the galaxy that pierces through the obscuring dust in Hubble’s optical light image. Spitzer also sees an otherwise hidden disk of stars within the dust ring. The Chandra X-ray image shows hot gas in the galaxy and point sources that are a mixture of objects within M104 as well as quasars in the background. The Chandra observations show that diffuse X-ray emission extends over 60,000 light years from the center of the M104. (The galaxy itself spans 50,000 light years across.) In sonifying these data, we can listen to each type of light either separately or together. Either option begins at the top and scans toward the bottom of the image. The brightness controls the volume and the pitch, meaning the brightest sources in the image are the loudest and highest frequencies. The data from the three telescopes are mapped to different types of sounds. The X-rays from Chandra sound like a synthesizer, Spitzer’s infrared data are strings, and optical light from Hubble has bell-like tones. The core of the galaxy, its dust lanes and spiral arms, and point-like X-ray sources are all audible features in the sonification of these data.
These sonifications were led by the Chandra X-ray Center (CXC) and included as part of NASA's Universe of Learning (UoL) program. The collaboration was driven by visualization scientist Kimberly Arcand (CXC), astrophysicist Matt Russo, and musician Andrew Santaguida (both of the SYSTEM Sounds project).
NASA's Marshall Space Flight Center manages the Chandra program. The Smithsonian Astrophysical Observatory's Chandra X-ray Center controls science from Cambridge Massachusetts and flight operations from Burlington, Massachusetts. NASA's Universe of Learning materials are based upon work supported by NASA under cooperative agreement award number NNX16AC65A to the Space Telescope Science Institute, working in partnership with Caltech/IPAC, Center for Astrophysics | Harvard & Smithsonian, and the Jet Propulsion Laboratory.
Different telescopes detect different types of light. Much of what they capture is recorded as digital data. Those data can then be translated into visuals, or even sounds. In today’s release, the data from three different astronomical observations is presented in collections of visualizations, and sonifications.
The first collection features observations of the system R Aquarii. There, a white dwarf star and a red giant star are in orbit around one another. In the composite visualization, the two stars are represented by brilliant white dots at the center of the image. The stars sit at the center of a giant, wispy orange cross that extends to all four edges of the image. This structure is evidence of outbursts generated by the pair of stars. A wavy line of soft, purple shapes, dot the horizontal bar of the cross. These shapes represent an X-ray jet from the white dwarf star. The jet creates shockwaves as it bangs into surrounding material. In the related sonifications, a radial arm sweeps clockwise around the image. Tones similar to a xylophone, or set of singing bowls, play when the sweeping arm encounters the wispy orange cross. The purple shapes are transformed into synthetic, windy purrs. The further from the center of the image, the higher the notes. And the brighter the [light] source, the louder the volume.
The second collection features observations of Stephan’s Quintet, a gathering of four galaxies held together by gravity. The fifth galaxy appears to be part of the group from our perspective, but is in fact much closer to us. The composite visualization combines optical, X-ray, and infrared data. In it, the galaxies resemble bright white dots surrounded by pale blue clouds. The distinct clouds are marbled with red veins, and connected by bright blue streaks. In the composite sonification, a faint line sweeps down the image from the upper edge to the bottom. Notes pluck and ping as the line passes background stars and galaxies. The bright Quintet of featured galaxies conjure sounds of deep winds and high-pitched wails.
The third collection features observations of a large galaxy known as Messier 104. Messier 104 is a spiral galaxy, but from Earth, we see its edge, not its face. In the composite visualization, Messier 104 resembles a misty purple cloud with a bright white core, encircled by a horizontal ring of spiraling arms. In the background are dozens of bright blue dots, which represent distant stars and galaxies. Several sonifications have been created for Messier 104. Some feature a single band of light, such as infrared or optical. Others are composite sonifications, combining the source data from several telescopes to create symphonies. In each, gently arching horizontal lines sweep down the image from top to bottom, prompting thrums, whirs, and whistles of various pitches, when they encounter light of varying brightness from different sources.