Space Scientists Find That Solar Wind Becomes Music In The Right Hands

Morales, a doctoral student at UC Berkeley's Center for New Music and Audio Technologies (CNMAT), has made a name for himself in the computer music field, generating music using rules or algorithms seldom associated with music.

"We are surrounded by computers and technology, we're being hit by media all the time, so you have to use it to create art," he said. "I see technology as a traditional tool for composition like Bach used the pipe organ in his time."

He was an obvious choice to work with physicists at UC Berkeley's Space Sciences Laboratory on a piece of software to convert data from a pair of NASA satellites comprising the Solar TErrestrial RElations Observatory, or STEREO, into sound, a concept that has acquired the name "sonification."

STEREO, scheduled for launch later this year, will provide a stereoscopic view of the sun and solar explosions called coronal mass ejections, which generate space storms that affect Earth. The IMPACT (In-situ Measurements of Particles and CME Transients) suite of instruments aboard STEREO, however, focuses, not on pretty pictures, but on the wind of electrons and ions from the sun, and the magnetic field of the sun.

Physicist Janet Luhmann, the principal investigator for IMPACT, realized that the data these instruments capture could be used to generate an audio counterpart to the STEREO images, not only drawing attention to the IMPACT data - typically not as sexy as the colorful pictures of the sun - but perhaps providing scientific value, too.

"You can look at wiggly lines, and you can look at spectrograms, which are kind of rainbow plots, and your eyes can give you certain feedback, but sometimes you hear patterns you don't see readily," she said. "I see the sonification as possibly adding to the ability to recognize certain kinds of characteristic behaviors."

With one of the STEREO satellites, dubbed A, leading Earth in its orbit around the sun and the other, B, following, the cameras and instruments will tell scientists how large the solar bursts are and how they vary from place to place and over time. Such data could easily be converted into sound, even music.

"If you have the record from STEREO A played in one ear and from STEREO B played in the other ear, you could hear particles arriving first in the right ear and later in the left ear, or hear a change in intensity as a crescendo," said Luhmann. "If you made the particular scale or note translation related to particle energy, you could see whether it was more energetic in one ear than another. It's really got acute potential for not only being a gee whiz kind of thing, but also conveying a sense of the physical thing happening, which is invisible."

Luhmann's colleague, Space Sciences Laboratory physicist Laura Peticolas, hired Morales to create a computer program, like a video game, that converts data from the instruments aboard IMPACT into sound. Together, they created three programs, one for kids that explains how numbers can be translated into music, one called "STEREO Spectro" that lets the general public play with the "sounds of space," and one called "Incandescence 1.1" for musicians who want to experiment with the sounds or weave them into a composition.

"Most people make this data sound like a solar wind, with the sound increasing and decreasing as the data intensity increases or decreases, which is a very literal translation of what's happening," Morales said. "But we wanted to ask, 'How can we look at the data in a new way? How can we map the data to increase the listenability, to make the music more appealing?' This way we can explore a new type of aesthetic."

One interpretation involves resonators, a tool developed at CNMAT by Adrian Freed. Morales uses these resonators to create new instruments based on resonance patterns inherent in the piano, "like building new pianos with a different sound-color perspective."

Morales tested his software with solar wind data from a satellite already orbiting Earth, NASA's Advanced Composition Explorer (ACE), and liked the results so much he incorporated them into a composition, "Turning Point," that was performed in 2004 by the University of Guanajuato's Philharmonic Orchestra. For that piece, Morales used two channels of data to determine the pitch, two others to set the rhythm, and two others to fix the dynamics, either forte or piano.

"You can make it as musical as you want," he said. "You can design your mapping strategies to make the generated sound tonal, D mayor for instance, or make intervals representing any rhythmic model you would like to explore. You are also able to configure the orchestration of the resultant sound to get the effect of a string quartet, a piano trio brass quintet, etc."

Peticolas noted that most sonification is akin to taking radio waves, which are inaudible, and shifting their frequency into the audio range.

However, "a direct translation of the data to sound may not be the best way for us to listen to it," she said. "The advantage of bringing Roberto on the project is that he is not stuck in the data. He has helped us think of different ways to make the sonification both musical and useful."

The software is already available for download from the laboratory's "Sounds of Space" Web site, http://cse.ssl.berkeley.edu/impact/sounds.html, but the proof of the pudding will be after STEREO's launch this summer, when data will be posted on the Web for anyone to download and turn into music. While Morales will have returned to Guanajuato with a newly minted Ph.D. from UC Berkeley, he hopes that the sonification software will bring people closer to what's happening in space.

"I see this idea of generating music from different sources - animals, the sea, light, space, the sound of the environment - as ways of getting close to nature," he said. "The musical technology expands your language as an artist and gives you a more complete vision of what you experience."