Star, galactic and black hole

• Astronomical data from three new objects has been translated into sound as part of a data sonification project.
• The Chandra Deep Field, the Cat’s Eye Planetary Nebula, and the Whirlpool Galaxy are the latest objects to turn their data into sound.
• The data comes from the Chandra X-ray Observatory as well as other NASA telescopes in space.
• Sonication of data allows users to be able to hear information from cosmic objects as well as see them.

This latest installment in our data sonification series features three diverse cosmic scenes. In each of them, astronomical data collected by NASA’s Chandra X-ray Observatory and other telescopes is converted into sound. Data sonication maps the data from these space telescopes into a form that users can hear instead of just seeing, embodying the data in a new form without changing the original content.

Chandra Deep Field

This is the deepest x-ray image ever taken, representing over seven million seconds of Chandra’s observation time. For this reason, and because the observed field is in the southern hemisphere, astronomers call this region the “Chandra Deep Field South”. At first glance, this image may appear to be a view of stars. On the contrary, almost all of these different colored dots are black holes or galaxies. Most of the former are supermassive black holes that reside in the center of galaxies. In this data sonification, the colors dictate the tones as the bar moves from the bottom of the image to the top. Specifically, colors towards the red end of the rainbow are heard as low tones while colors towards purple are assigned to higher colors. Light that appears bright white in the image is heard as white noise. The wide range of musical frequencies represents the full range of x-ray frequencies collected by Chandra from this region. In the visual color image, this wide range of frequencies in the x-rays had to be compressed to be represented as red, green and blue for low, medium and high energy x-rays. Played as a sound, however, the full range of data can be experienced. As the room sweeps upward, the stereo position of sounds can help distinguish the position of sources from left to right.

Cat’s eye nebula

When a star like the Sun starts to run out of helium to burn, it will blow out huge clouds of gas and dust. These explosions can form spectacular structures like the one seen in the Cat’s Eye Nebula. This cat’s eye image contains both x-rays from Chandra around the center and visible light data from the The Hubble Space Telescope, which show the series of bubbles expelled by the star over time. To listen to this data, there is a radar-type sweep that moves clockwise from the center point to produce the height. Light that is farther from the center is heard at higher pitches while brighter light is stronger. X-rays are represented by harsher sound, while visible light data is softer. The circular rings create a constant buzz, interrupted by some ray sounds in the data. The ascending and descending footsteps that can be heard are due to the radar sweep passing through the shells and jets in the nebula.

Messier 51

Messier 51 (M51) is perhaps best known by its nickname the Whirlpool Galaxy because its orientation facing the Earth reveals its coiled spiral arms. This gives the telescopes here a view of another spiral galaxy similar to our Milky Way, the structure of which we cannot observe directly from our position within it. As with the cat’s eye, the sonication starts at the top and moves radially around the image in a clockwise direction. The ray is mapped to the notes of a melodic minor scale. Each wavelength of light in the image obtained from NASA telescopes in space (infrared, optical, ultraviolet and x-rays) is assigned to a different frequency range. The sequence begins with the sounds of the four types of light, but then moves separately through data from Spitzer, Hubble, GALEX, and Chandra. At wavelengths in which the spiral arms are prominent, the steps move upward as the spiral moves away from the nucleus. A constant low hum associated with the luminous core can be heard, punctuated by short sounds from compact light sources in the galaxy.

These sonifications of the Deep Field, Cat’s Eye and Whirlpool galaxy were conducted by the Chandra X-ray Center (CXC). The collaboration was led by visualization researcher Dr. Kimberly Arcand (CXC), astrophysicist Dr. Matt Russo and musician Andrew Santaguida (both from the SYSTEM Sound project).