The band Echo Movement wanted something distinct so they asked Georgia Tech for help. Rhythms, pitches and tempos needed to evoke a "heavenly" sound so the musicians and students went to work with existing data gathered by NASA's Kepler telescope. They began with a binary star, Kepler 4665989, which had brightness levels recorded for more than a year. The star dimmed and brightened each time its companion star crossed its path, providing varying brightness measurements.
"Those numerical values were loaded into our Sonification Sandbox software to create sequences of sonified musical pitches," said Riley Winton, a psychology student and leader of the project. "The process put us on the right track. When the band reviewed it and requested timbres instead of pitches, we audified the data."
The team played the varying brightness levels as waveforms to create a different sound, then cleaned the signal and removed some of the ambient sound before sending audio pitches to the band. Echo Movement looped the sounds and composed them into a four-part harmony. For the final step, the students used a different binary star, Kepler 10291683, to adjust the timbre even further by adding a tremolo effect. This created a shuddered, natural sound rather than a flat, computerized noise.
The final result is a melody that will be used in the intro of Echo Movement's song "Love and the Human Outreach," which will be released in September. The intro is here.
"People have made music with space sounds before, but largely using pulsars and space events that can be recorded in the radio spectrum. We wanted something completely off the chart," said band member David Fowler, who was encouraged by Edna DeVore at the SETI Institute to look at the Kepler Mission. "Discovering planets around other stars is a relatively new science worthy of everyone's attention and digs deep at the core of humanity's most basic quest to orient itself in reality," he said.
The project's goal, to create an authentic, aesthetic sound, was a success. The melody is further proof that sonification can be a valuable tool when working with large data sets.
"The Sonification Lab receives a lot of requests to convert scientific data into sound, but this one was truly unique," said School of Psychology Professor Bruce Walker. "It's not often that we have a chance to help an actual star compose music.
"Sound is the best pattern recognition tool we have. Instead of visually scanning through a long list of numbers, looking for patterns or random occurrences, sometimes it's easier to create an audio file and listen for them. Very interesting patterns can often be discovered by using sound."
The Georgia Tech team will present the sonification process at the International Conference on Auditory Display (ICAD) in Atlanta June 18 – 21, 2012.