Patagonia (above & below) “demon rat” http://go.nasa.gov/2idXyXs
Heavenly Sounds: Hearing Astronomical Data Can Lead to Scientific Insights
Converting the energetic hail of cosmic radiation into audible tracks has produced better understanding of the solar wind and other astrophysical events—along with musical enjoyment
By Adam Hadhazy | April 30, 2014
COSMIC SYMPHONICS: The “solar wind,” a barrage of charged particles streaming from the sun , is one example of an astrophysical phenomenon that can be translated into audible sound.
While on a spacewalk, if you plucked a guitar’s strings, you would, of course, hear nothing—sound waves cannot travel through space’s near-vacuum. Although soundless to our ears, however, the cosmic “void” is actually a cacophony of zipping particles and light waves. As atomic nuclei and radiation strike scientific instruments, they can be construed, in effect, as the “sounds” of space. We can listen in on the universe’s hidden melodies. That is because the sequence or intensity of detected particles can be converted into vibrations that fall within our human hearing range. Scientists have long transformed inaudible data in this manner into audible information—take, for instance, the “beep…beep…beep” of a heart-rate monitor.
DEEP-SPACE SONATA: A conversion to audible sound of one of the most powerful explosions on record in the universe, the gamma-ray burst GRB 080916C. The number of notes played represents the gamma rays received by the Fermi Gamma-ray Space Telescope. The accompanying sounds correspond to the probability of the rays emanating from the burst itself, with lowest-likelihood rays played as a harp, medium by a cello and highest-probability by a piano.
Many kinds of astronomical data have received this “sonification” treatment, ranging from solar wind particles streaming off our sun to gamma rays blasting across billions of light-years. These audible conversions have aided public outreach and allowed the vision-impaired to experience the universe’s proceedings.
But hearing data, it turns out, also can open new scientific frontiers. That’s thanks to the remarkable human ability to parse sound for patterns and meaning. “The auditory system is the best pattern-recognition device that we know of,” says Bruce Walker, a professor of psychology and director of the Georgia Institute of Technology’s Sonification Lab. “If you’re looking through a data set and trying to understand what’s going on, it’s often easier and more efficient to listen to the sound of it rather than looking at a screen or a printed version.” A paper published in The Astrophysical Journal in 2012 relied on such an approach. The finding—that varying forms of charged carbon atoms spewed by the sun can reveal differences in solar atmospheric temperatures—sprung from tuning in to audibilized data. “I was listening to some raw solar data and I heard this underlying hum,” says paper co-author Robert Alexander, a sonification specialist with the Solar and Heliospheric Research Group at the University of Michigan.
SUNNY ANTHEM: The audio that Alexander was listening to when he noticed an underling “hum.” The sound file corresponds to audibilized data of charged atoms, including carbon, within the solar wind from 1998 to 2010 recorded by a spectrometer onboard NASA’s Advanced Composition Explorer spacecraft.
The frequency of the hum, 137.5 hertz, corresponded to a period of around 27 days in the compressed data set. That’s how long it takes the sun to complete a rotation. The duration implied a link to a surface or atmospheric feature, such as a region belching out a particular kind of solar wind, brought back around to face Earth periodically. “It gave me an inkling that this data could potentially be important,” Alexander says. The ratios of carbon ions proved a reliable indicator of whether solar wind is either of two types, “fast” or “slow.” That in turn speaks to the temperatures of the source regions for the wind in the solar atmosphere.
NASA, noting the innovative results, awarded Alexander a fellowship to further explore sonification applications, and new papers are pending. “This technique can be applied to an extremely wide array of data,” Alexander says. “If you think about music as the ‘universal language,’ then you can think of audio as a universal platform for scientific inquiry. You can take data from any number of different sources, convert them into an audio file and then push ‘play.'”
Over its history space sonification has yielded a number of other novel insights. Back in World War I primitive radio equipment picked up the phenomenon known as “whistlers.” Decades later these spooky signals were tied to lightning strikes. Lightning sets off an electromagnetic wave in the soup of ionized gas, or plasma, surrounding Earth. High frequencies generated during the event travel faster in this milieu, arriving at a receiver before lower-sounding frequencies—hence, making a whistlelike effect. Explicating how whistlers worked helped advance the understanding of plasma physics in Earth’s radiation belts.
West Coast of Chile (above) http://go.nasa.gov/2ijxtUT
http://go.nasa.gov/2ijxOa2 (above) slightly enhanced for structure & sepia
http://go.nasa.gov/2ie2POS slightly enhanced
West coast of Chile (above) http://go.nasa.gov/2ijvy2x
http://go.nasa.gov/2ie1OpN / slightly enhanced (above)
one more gruesome detail…Galapagos Islands west of S. Amer.
detail: the intense r/f ribbing waves show up better in Sepia, also slight enhanced contrast
Galapagos Islands west of South America (six above) http://go.nasa.gov/2ijttUd