Messier 51 (M51) is perhaps better known by its nickname of the Whirlpool Galaxy because its face-on orientation to Earth reveals its wound-up spiral arms. This gives telescopes here a view of another spiral galaxy similar to our Milky Way, whose structure we cannot observe directly from our position within it. 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. At wavelengths in which the spiral arms are prominent, the pitches creep upwards 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.
Video credit: JNASA/CXC/SAO/K.Arcand, SYSTEM Sounds (M. Russo, A. Santaguida)