Since 2020, a "sonification" project has transformed astronomical data from some of the world's most powerful telescopes into sound.
Three new objects — a star-forming region, a supernova remnant, and a black hole at the center of a galaxy — are being released.
Each sonification has its own technique to translate the astronomical data into sound.
The sonification project is led by staff of NASA's Chandra X-ray Observatory and the Universe of Learning.
Space is mostly quiet. Data collected by telescopes is most often turned into silent charts, plots, and images. A "sonification" project led by NASA's Chandra X-ray Observatory and NASA's Universe of Learning program transforms otherwise inaudible data from some of the world's most powerful telescopes into sound. This effort makes it possible to experience data from cosmic sources with a different sense: hearing.
The latest installment of this sonification project features a region where stars are forming (Westerlund 2), the debris field left behind by an exploded star (Tycho's supernova remnant), and the region around arguably the most famous black hole (Messier 87). Each sonification has its own technique to translate the astronomical data into sounds that humans can hear.
Westerlund 2 (above)
This is a cluster of young stars — about one to two million years old — located about 20,000 light years from Earth. In its visual image form, data from Hubble (green and blue) reveals thick clouds where stars are forming, while X-rays seen from Chandra (purple) penetrate through that haze. In the sonified version of this data, sounds sweep from left to right across the field of view with brighter light producing louder sound. The pitch of the notes indicates the vertical position of the sources in the image with the higher pitches towards the top of the image. The Hubble data is played by strings, either plucked for individual stars or bowed for diffuse clouds. Chandra's X-ray data is represented by bells, and the more diffuse X-ray light is played by more sustained tones.
Beginning in the center, the sonification of the Tycho supernova remnant expands outward in a circle. The image contains X-ray data from Chandra where the various colors represent small bands of frequency that are associated with different elements that are moving both toward and away from Earth. For example, red shows iron, green is silicon, and blue represents sulfur. The sonification aligns with those colors as the redder light produces the lowest notes and blue and violet create the higher-pitched notes. Color varies over the remnant, but the lowest and highest notes (red and blue) dominate near the center and are joined by other colors (mid-range notes) towards the edge of the remnant. White corresponds to the full range of frequencies of light observable by Chandra, which is strongest toward the edge of the remnant. This light is converted to sound in a more direct way as well, by interpreting frequencies of light as frequencies of sound and then shifting them lower by 50 octaves so that they fall within the human hearing range. The different proportions of iron, silicon, and sulfur across the remnant can be heard in the changing amounts of the low-, mid-, and high-frequency peaks in the sound. The field of stars in the image as observed by Hubble is played as notes on a harp with the pitch determined by their color.
The giant black hole in Messier 87 (M87 for short) and its surroundings have been studied for many years and by a range of telescopes including Chandra (blue) and the Very Large Array (red and orange). This data shows that the black hole in M87 is sending out massive jets of energetic particles that interact with vast clouds of hot gas that surround it. To translate the X-rays and radio waves into sound, the image is scanned beginning at the 3 o'clock position and sweeping clockwise like a radar. Light farther from the center is heard as higher pitched while brighter light is louder. The radio data are lower pitched than the X-rays, corresponding to their frequency ranges in the electromagnetic spectrum. The point-like sources in X-ray light, most of which represent stars in orbit around a black hole or neutron star, are played as short, plucked sounds.
The data sonification project is led by the Chandra X-ray Center (CXC) with NASA's Universe of Learning program. NASA's Science Activation program strives to enable NASA science experts and to incorporate NASA science content into the learning environment effectively and efficiently for learners of all ages. The collaboration was driven by visualization scientist Dr. Kimberly Arcand (CXC) and astrophysicist Dr. Matt Russo with 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, the Center for Astrophysics | Harvard & Smithsonian, and the Jet Propulsion Laboratory.
Fast Facts for Westerlund 2:
X-ray: NASA/CXC/SAO/Sejong Univ./Hur et al; Optical: NASA/STScI; Sonification: NASA/CXC/SAO/K.Arcand, SYSTEM Sounds (M. Russo, A. Santaguida)
September 16, 2021
About the Sound
Left to right sweep across image (stereo position also indicates left-right position within the image)
Note pitch indicates the vertical position (higher pitches towards the top of the image)
Volume indicates the brightness
X-ray sources (Chandra) are played by bells, with the more diffuse X-ray light is played by purer sustained tones
Optical light (Hubble) played by strings: stars are plucked strings and nebula are sustained strings
X-ray: NASA/CXC/RIKEN & GSFC/T. Sato et al; Optical: DSS; Sonification: NASA/CXC/SAO/K.Arcand, SYSTEM Sounds (M. Russo, A. Santaguida)
September 16, 2021
About the Sound
Image is scanned form the inside out by a circle that starts in the middle and expands
The volume indicates the brightness
The stereo position indicates the left-right position in the image
X-ray layer (Chandra): the pitch indicates the color of light under this expanding circle (redder light produces lower notes, blue-violet produces higher notes, other colors are in between). Color varies wildly over the remnant but red/blue (low/high notes) dominate near the middle and are joined by other colors (mid-range notes) towards the edge of the remnant.
Spectra layer (Chandra): X-ray spectra is converted to sound. Frequencies of light are interpreted as frequencies of sound and then shifted by 50 octaves, (about 8 piano widths) to fall within the human hearing range. This is strongest towards the edge of the remnant where it appears white. Three high peaks are due to Iron, Silicon, and Sulfur (from left to right). Their changing proportions within different regions of the remnant can be heard in the changing amounts of the low, mid, and high frequency peaks in the sound.
Optical layer (Hubble): same mapping as the X-ray layer (color controls pitch, brightness controls volume) but notes are played on a harp, one for each