Gamma-ray bursts (GRBs) are one of the universe's most dramatic spectacles, shining hundreds of times brighter than a typical supernova and "a million trillion times as bright as the sun," according to NASA. But few humans ever get to enjoy one, since GRBs are rare, last just a few seconds and occur billions of light-years away. It also doesn't help that gamma rays are too energetic for human eyes to perceive.
Thanks to NASA's Fermi Large Area Telescope, however, not only can we indirectly "see" GRBs, but now we can "hear" them, too. And compared with the chaotic sonification of a solar storm, the audio translation of a GRB is downright symphonic.
Published Thursday on the Fermi blog, this cosmic concert came from GRB-080916C, an especially strong gamma-ray burst that NASA recorded in September 2008. To make it audible, Fermi researchers converted the GRB's energy signature into musical notes played on a harp, a cello and a piano. They also made an animation of its photon frequency, and then paired these sights and sounds in the following video clip:
GRB-080916C was one of the most energetic gamma-ray bursts ever recorded, but like most GRBs, it didn't last very long. The brightest part ended after less than a minute, so the actual event was much faster and shorter than the nearly four-minute musical version. The Fermi team didn't want it to sound too frantic, though, so they slowed it down by a factor of five to help listeners distinguish individual gamma rays.
As for how they converted those rays to music, the team explains thusly:
"In translating the gamma-ray measurements into musical notes, we assigned the photons to be 'played' by different instruments (harp, cello or piano) based on the probabilities that they came from the burst. ... In the beginning of the song, before the burst starts, the harp plucks out a few lonely notes. After about half a minute, the piano joins in on top of the harp background, and the notes begin to pile on more and more rapidly. The cello enters the scene as the burst begins in earnest."
Hearing gamma-ray music may not yield much scientific insight about the cosmos, but it can make a weird, distant phenomenon like GRBs seem more real to non-scientists — and maybe even boost interest in deep-space astronomy. If you want to follow along with the music, the Fermi folks offer this guide to the animation:
"The top panel shows each individual gamma ray. The colors refer to low- (red), medium- (blue) and high- (green) quality gamma rays (played by harp, cello and piano, respectively). The energy of the gamma ray is on the y-axis (higher-energy gamma rays are toward the top of the plot) and the arrival time of the gamma ray is on the x-axis (later-arriving gamma rays are farther to the right). The vertical white line tells you where the music is currently playing. The bottom panel shows the number of gamma rays in each time slice."
Also on MNN:
- Study: Gamma rays could end life on Earth
- Solar flare breaks gamma-ray light record
- What does a solar storm sound like?