A Tour of Data Sonification: Stellar, Galactic, and Black Hole

As part of our ongoing data sonification series, three new images have now been released. In this project, astronomical data collected by NASA's Chandra X-ray Observatory and other telescopes are translated into sounds. Data sonification converts the data from these space-based telescopes into a form that users can hear instead of only see, embodying the data in a new form without changing the original content.

These three images include some of the most famous objects associated with Chandra. The first is the Chandra Deep Field, which contains some 7 million seconds worth of the telescope's observing time. At first glance, this image may appear to be a view of stars. Rather, almost all these different colored dots are black holes or galaxies. Most of the former are supermassive black holes that reside at the centers of galaxies. In this data sonification, the colors dictate the tones as the bar moves from the bottom of the image to the top. More specifically, colors toward the red end of the rainbow are heard as low tones while colors towards purple are assigned to higher ones. Light that appears bright white in the image is heard as white noise.

The second new image is the planetary nebula known as the Cat's Eye. 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. To listen to these data, there is a radar-like scan that moves clockwise emanating from the center point to produce pitch. Light that is further from the center is heard as higher pitches while brighter light is louder.

The final member of this trio of newly sonified images is the Whirlpool Galaxy, which also goes by its formal name of Messier 51. The Whirlpool is oriented face-on to Earth, giving telescopes here a view of another spiral galaxy similar to our Milky Way. As with the Cat's Eye, the sonification begins at the top 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 obtained from NASA telescopes in space (infrared, optical, ultraviolet, and X-ray) is assigned to a different frequency range. The sequence begins with sounds from all four types of light, but then separately moves through the data from Spitzer, Hubble, GALEX, and Chandra.