Sonifications

Ever wondered what the music of the spheres would sound like? Hubble brings us cosmic sights, but these astronomical marvels can be experienced with other senses as well. Through data sonification, the same digital data that gets translated into images is transformed into sound.

Elements of the image, like brightness and position, are assigned pitches and volumes. No sound can travel in space, but sonifications provide a new way of experiencing and conceptualizing data. Sonifications allow the audience, including blind and visually impaired communities, to “listen” to astronomical images and explore their data.

The Mice Galaxies are a colliding pair of galaxies, that will eventually merge into a single galaxy. They’re located about 300 million light-years away in the constellation Coma Berenices. In this data sonification, scientists represented brightness with volume and pitch – brighter light is louder and lower pitched. The vertical position of objects in the image is used to control the pitch of sustained musical strings, and cymbals swell following the brightness of the galaxy cores. Listen for a cymbal crash played for the foreground star with diffraction spikes, too!

This data sonification of Arp 140 shows a pair of interacting galaxies. The leftmost galaxy is a barred spiral galaxy known as NGC 275, and the right-side galaxy is a lenticular galaxy called NGC 274. In barred spiral galaxies, a bar of stars runs through the central bulge of the galaxy (seen here as a bright-white, vertical haze in NGC 275). Lenticular galaxies, on the other hand, are classified somewhere between elliptical and spiral galaxies, getting their name from the edge-on appearance that resembles a disk. They typically don’t have much gas and dust and are made up primarily of old stars.

Scientists sonified the data in this image, assigning pitch to color for the image as a whole (bluer light is higher, redder is lower). Pitch is mapped to brightness for the resolved stars and background galaxies, based on their apparent size – objects that appear bigger are lower, and smaller are higher in pitch. Brighter light is louder throughout the image. 

This data sonification of the star V838 Monocerotis, or V838 Mon, shows two Hubble images taken almost seven months apart. A pulse of light from the central star illuminates clouds of dust and gas surrounding V838 Mon.

This star is located about 20,000 light-years away, at the outer edge of our Milky Way Galaxy. In this sonification, scientists mapped brightness to pitch and volume, and the surrounding stars are pitched to musical notes. The sonification radiates outward from the center of the first image of the star, taken on May 20, 2002, and then fades away. The sonification then radiates outward from the center of the second image of the star, taken on Dec. 17, 2002.

RS Puppis is a glittering star 200 times larger than our Sun and wreathed with dust reflecting starlight. Located about 6,500 light-years away, this star rhythmically brightens and dims over a six-week cycle. In this sonification, scientists represent data in the image as sound for a new, festive way of experiencing RS Puppis. Pitch is assigned based on direction from the center; as the circle travels inward, points at the top of the circle are mapped to higher notes and points near the bottom are mapped to lower notes. Light toward the left is heard more in the left speaker and light toward the right is heard more in the right speaker. Additionally, brightness in the image is mapped to louder volume.

Pismis 24 is a stunning star cluster that lies within the nebula NGC 6357, which resides about 8,000 light-years away. In this sonification of the Hubble image, a top-down scan maps brightness to volume and pitch for both the stars and nebula. The stars are assigned to musical pitches played on a classical guitar (brighter stars are louder and higher pitched), and the nebula uses a continuous range of frequencies (brighter regions are louder and higher pitched). Red, green, and blue channels are mapped to low, medium, and high frequency ranges, respectively.

The majestic barred spiral galaxy NGC 1300’s arms hold blue clusters of young stars, pink clouds of star formation, and dark lanes of dust. NGC 1300 is considered to be prototypical of barred spiral galaxies. Barred spirals differ from normal spiral galaxies in that the arms of the galaxy do not spiral all the way into the center, but are connected to the two ends of a straight bar of stars containing the nucleus at its center. In this image, blue and red supergiant stars, star clusters, and star-forming regions are well resolved by Hubble across the spiral arms, and dust lanes trace out fine structures in the disk and bar. Numerous more distant galaxies are visible in the background, and are seen even through the densest regions of NGC 1300.

To represent this image with sound, scientists assigned louder volume to brighter light. Light farther from the center is pitched higher as a counterclockwise radar scans across the galaxy. NGC 1300 resides nearly 70 million light-years away in the constellation Eridanus.

Studied by scientists for decades, the black hole in Messier 87 (M87) gained celebrity status after the first release from the Event Horizon Telescope (EHT) project in 2019. This sonification does not feature the EHT data, but rather looks at data from other telescopes that observed M87 on much wider scales at roughly the same time. This image of a jet emerging from the nucleus of M87 contains three panels that feature: X-rays from the Chandra X-ray Observatory, visible light from Hubble, and radio waves from the Atacama Large Millimeter Array in Chile. The brightest region of the image is where the black hole is found, and the structure ejecting from it is the jet, produced by material falling onto the black hole. The sonification scans from left to right across the three-tiered image, with each wavelength mapped to a different range of audible tones. Radio waves are mapped to the lowest tones, visible data to medium tones, and X-rays to the highest tones. The brightest part of the image corresponds to the loudest portion of the sonification, which is where astronomers find the 6.5-billion solar mass black hole.

Welcome to one of the most active galaxies in our cosmic neighborhood, NGC 1569. This starburst galaxy creates stars at a rate 100 times faster than in our own galaxy, the Milky Way! Scientists represented information in this Hubble image with sound to create a beautiful sonification with a bottom to top scan. Brighter light is higher pitched and louder. The three color channels used to process this image are each given their own pitch range, with red representing lower pitches, green in medium pitches, and blue in high pitches.

Stretching over 100,000 light-years across, the galaxy dubbed Hoag’s Object is slightly larger than our own home galaxy, the Milky Way. The blue ring is dominated by clusters of young, massive stars, while the yellow nucleus consists of mostly older stars. In this sonification, a clockwise radar scan transforms data in the image into sound. Bright light is represented with louder volume, and light farther from the center is higher-pitched.

In this Hubble image, a super-hot, massive star is blowing an enormous bubble into space. Fittingly named the Bubble Nebula, this beautiful cosmic object is roughly seven light-years across and resides 7,100 light-years from Earth.

Scanned from top to bottom, color is mapped to pitch in this sonification of the nebula. The bright blue of the bubble can be heard as higher pitches; the red and orange regions’ lower pitches are heard most clearly at the beginning on the left and in the top half of the bubble in the middle. Brightness controls the volume and stars are represented by chimes.

This spectacular Hubble image of the Butterfly Nebula shows a colorful view of star death. The "wings" of the butterfly are regions of gas heated to more than 36,000° F (about 20,000° C) that are tearing across space at more than 600,000 miles an hour (966,000 kph)!

This sonification scans left to right. Vertical position is mapped to pitch – meaning that light towards the top of the image is higher pitched. The nebula is played on strings and synthetic tones, while stars are represented by digital harp. Brightness controls the volume, and the tilted hourglass orientation of the nebula produces an overall rising motion, with the prominent iron-rich jet producing a quick rise near the center.

About 5,000 light-years from Earth, the stunning nebula NGC 2392 formed after the demise of a star like our Sun. The fuzzy outer region of this nebula is a disk of material embellished with a ring of comet-shaped objects, with their tails streaming away from the central, dying star. The inner nebula's bright central region that resembles a ball of twine is really a bubble of material being blown into space by the central star's intense "wind" of high-speed material.

In this sonification, the image is scanned clockwise like a radar. The radius is mapped to pitch, so light farther from the center is higher pitched. The outline of the nebula’s shell can be heard in the rising and falling of pitch, punctuated by its spokes. Brightness controls the volume.

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 by 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.

This sonification of the 2014 Hubble Ultra Deep Field plays a single note for each galaxy in the image. The later the note plays in this musical piece, the farther away the galaxy is. The pitch of the note indicates the galaxy’s color (lower notes are redder, higher notes are bluer) and the volume indicates the galaxy’s apparent size. In just under a minute, we can hear back nearly 13 billion years to the farthest galaxies in that photo. The light we see from those galaxies was emitted when the universe was only a few hundred million years old.

Astronomers previously studied the Hubble Ultra Deep Field, a small section of space in the southern hemisphere constellation Fornax, in visible and near-infrared light in a series of images captured from 2003 to 2009. In this 2014 image, astronomers combined the full range of wavelengths available to Hubble, stretching all the way from ultraviolet to near-infrared light. The resulting image contains approximately 10,000 galaxies.

The Whirlpool Galaxy (M51) is named for its face-on orientation to Earth, which reveals its winding spiral arms. The sonification begins at the top of the image and moves radially around the image in a clockwise direction. The radius is mapped to notes of a melodic minor scale. Each wavelength of light in the image is mapped to a limited range of pitches, from low to high pitch, which corresponds to low to high light frequency: infrared, optical, ultraviolet, and then X-ray. The sequence begins with sounds from all four types of light, but then separately moves through the data from Spitzer (infrared), Hubble (visible), GALEX (ultraviolet), and Chandra (x-ray). At wavelengths in which the spiral arms are prominent, the pitches creep upward as the spiral reaches farther from the core. A constant, low hum associated with the bright core can be heard, punctuated by short sounds from compact sources of light within the galaxy. For more information on this sonification, visit the Chandra Observatory's sonification page.

When a star like the Sun begins to run out of helium to burn, it will blow off huge clouds of gas and dust. These outbursts can form spectacular structures such as the one seen in the Cat's Eye Nebula. This image of the Cat's Eye contains both X-rays from Chandra (around the center) and visible light data from the Hubble Space Telescope, which show the series of bubbles expelled by the star over time. A radar-like scan of the image emanates from the center point of the nebula and moves clockwise to produce pitch. Light that is further from the center is heard as higher pitches while brighter light is louder. The X-rays are represented by a harsher sound, while the visible light data sound smoother. The circular rings of the Cat’s Eye create a constant hum, interrupted by a few sounds from spokes in the data. The rising and falling pitches that can be heard are due to the radar scan passing across the shells and jets in the nebula. For more information on this sonification, visit the Chandra Observatory's sonification page.

On February 24, 1987 observers in the southern hemisphere saw a new object in the Large Magellanic Cloud, a small satellite galaxy to the Milky Way. This was one of the brightest supernova explosions in centuries and soon became known as Supernova 1987A. This time lapse shows a series of Chandra X-ray Observatory (blue) and Hubble Space Telescope (orange and red) observations taken between 1999 and 2013. In this image, the dense ring of gas ― which was ejected by the star before it went supernova ― begins to glow brighter as the supernova shockwave passes through. As the focus sweeps around the image, the data are converted into the sound of a crystal singing bowl, with brighter light being heard as higher and louder notes. The visible-light data are converted to a higher range of notes than the X-ray data, so both wavelengths of light can be heard simultaneously.

This image of the Bullet Cluster provided the first direct proof of dark matter, the mysterious unseen substance that makes up the vast majority of matter in the universe. X-rays from Chandra show where the "normal" matter (pink), in the form of hot gas, has been wrenched away from dark matter (blue), shown by Hubble and ground visible-light observations. The separation occurred during a collision of two massive galaxy clusters.

In converting this into sound, the data pan left to right, and each layer of data was limited to a specific frequency range. Data showing dark matter are represented by the lowest frequencies, while X-rays showing normal matter are assigned to the highest frequencies. The galaxies in the image revealed by Hubble data, many of which are in the cluster, are in mid-range frequencies. Then, within each layer, the pitch is set to increase from the bottom of the image to the top so that objects towards the top produce higher tones.

Located 40,000 light-years from Earth in the constellation Columba, this globular cluster is called Caldwell 73 or NGC 1851. A globular cluster is a spherical group of stars that are gravitationally bound to each other, with most of the stars concentrated at the cluster’s center.

As the radar scans around in this sonification, the radius of the stars is mapped to pitch, so stars farther from the center are higher pitched. The entire image is converted to the sound of a choir, while the orange and red stars are represented by a marimba, and the blue stars are represented by a glockenspiel.

The Crab Nebula is the expanding remnant of a supernova that occurred in 1054 A.D. Modern telescopes have captured its enduring engine powered by a quickly spinning neutron star that formed when a massive star collapsed. The combination of rapid rotation and a strong magnetic field generates jets of matter and anti-matter flowing away from its poles, and winds outward from its equator.

For the translation of these data into sound, which pans left to right, each wavelength of light has been paired with a different family of instruments. X-rays from Chandra X-ray Observatory (blue and white) are brass, optical light data from Hubble Space Telescope (purple) are strings, and infrared data from Spitzer (pink) can be heard in the woodwinds. In each case, light received towards the top of the image is played as higher pitched notes and brighter light is played louder.

Several hundred galaxies reside within the core of galaxy cluster Abell 370, located approximately 4 billion light-years away from Earth. The mass of the galaxies distorts space, and magnifies and bends the light coming from distant background galaxies. This effect, called "gravitational lensing," makes it possible to see extremely distant objects.

This sonification scans from left to right. Sound waves are generated based on the brightness and position of the cosmic objects in the image. Brighter light is converted into louder sound, and the frequency increases from the bottom to the top of the image.

The Helix Nebula is 655 light-years away and three light-years across. When a low-mass star sheds outer material near the end of its life, nebulae like this form.

In this sonification, which scans from left to right, red light is assigned lower pitches and blue light is assigned higher pitches. Just as the frequencies of light increase from red to blue, frequencies of sound increase from low to high pitches.

This Hubble image of two galaxies colliding resembles a face. The “eyes” are the bright cores of the two galaxies, and the outline of the face is a ring of young, blue stars. The system is catalogued as Arp-Madore 2026-424 (AM 2026-424), from the Arp-Madore "Catalogue of Southern Peculiar Galaxies and Associations." The system resides 704 million light-years from Earth.

In this sonification, data is scanned from left to right. Vertical position is mapped to pitch and brightness is mapped to volume.

Hubble’s 30th anniversary image of the Cosmic Reef shows two nebulae, NGC 2014 and NGC 2020. Located in the Large Magellanic Cloud, a satellite galaxy to our own Milky Way, the Cosmic Reef is 163,000 light-years away.

The red nebula is a stellar nursery, while the blue nebula is created by material ejected from a massive star. Red indicates the presence of hydrogen and nitrogen, and blue indicates oxygen. Color is mapped to pitch in this sonification, which scans from left to right, with blue assigned higher pitches and red lower pitches.

The immense gravity created by massive clusters of galaxies can distort and magnify the light of much farther objects behind them, an effect called gravitational lensing. In this image, galaxy cluster RXC J0142.9+4438 provides warped glimpses of very distant galaxies that would not otherwise be visible.

This sonification scans from left to right. Objects near the bottom of the image produce lower notes, while those near the top produce higher ones. Stars and compact galaxies create short, clear tones, while sprawling galaxies emit longer notes that change pitch. The higher density of galaxies near the center of the image results in a swell of mid-range tones halfway through the video.

These pillars of gas and dust in the Eagle Nebula are regions of starbirth. The aptly named "Pillars of Creation" hide newborn stars in their wispy columns. Stretching roughly 4 to 5 light-years, the towers are a relatively small feature of the entire Eagle Nebula, which spans 70 by 55 light-years.

In the sonification, sounds are generated by moving horizontally across the image from left to right as seen in both visible and X-ray light. The vertical position of the recorded light controls the pitch. Particular attention is paid to the structure of the pillars, which can be heard as sweeps from low to high pitches and back. For more information on this sonification, visit the Chandra X-ray Observatory’s sonification page.

The center of our Milky Way galaxy houses a massive black hole surrounded by a dense nest of stars and bright clouds. This image combines observations from the Hubble, Chandra, and Spitzer space observatories, and shows energetic regions of starbirth, hundreds of thousands of stars, glowing dust clouds, and intense activity near the galactic core.

This sonification scans from left to right. The light of objects located towards the top of the image is pitched higher, while the intensity of the light controls the volume. Stars and compact sources are converted to individual notes while extended clouds of gas and dust produce an evolving drone. A crescendo happens at the lower right of the image. This is where the 4-million-solar-mass supermassive black hole at the center of the galaxy resides, and where the clouds of gas and dust are the brightest. For more information on this sonification, visit the Chandra Observatory's sonification page.