ROBERT SIEGEL, HOST:
This week, thousands of astronomers gathered just outside Washington, D.C., for their annual meeting. The talk there was of big things like the birth of universe and the death of stars. NPR's Geoff Brumfiel met one scientist who was chronicling the last moments of a star's life, using sound.
GEOFF BRUMFIEL, BYLINE: Alicia Soderberg works at Harvard University. She says it's tricky to witness a star's death.
ALICIA SODERBERG: Because if you want to watch a star die, you have to be in the right place at the right time, and often we're not. So all we can do is do a stellar autopsy and go back and try to pick up the pieces and figure out what happened.
BRUMFIEL: Soderberg's autopsy involves collecting every signal she can from the explosions of dying stars: radio waves, light, X-rays. Then she tries to make sense of it.
SODERBERG: The data analysis itself is very detailed.
BRUMFIEL: Now, a few years ago, Soderberg met a graduate student.
WANDA DIAZ-MERCED: Wanda Liz Diaz-Merced.
BRUMFIEL: Diaz-Merced is blind, so she studies astronomy not with sight but by turning data into sound.
DIAZ-MERCED: I have been able to listen, for example, to meteors passing through the atmosphere, solar storms. That is just to give you a gist.
BRUMFIEL: Stars, comets, planets, all sound different.
DIAZ-MERCED: Every sound I listen from the skies, it has its own voice.
BRUMFIEL: Soderberg wondered what all the data from her dying stars might sound like. So she had her team work with Diaz-Merced to translate data points into musical notes. Soderberg says each signal collected as part of her autopsy gets its own place in the orchestra.
SODERBERG: The radio gets the drums, the X-ray gets the harpsichord, and everything in between gets a different instrument, like a violin or a flute.
(SOUNDBITE OF MUSIC)
BRUMFIEL: Listening to these signals together, Soderberg started hearing things - things she hadn't noticed when she looked at graphs and numbers.
SODERBERG: I hear the data points.
(SOUNDBITE OF MUSIC)
SODERBERG: I hear a very fast crescendo and I hear the sound doesn't trickle off as slowly as I would expect it to.
(SOUNDBITE OF MUSIC)
SODERBERG: This one, it sounds completely different.
(SOUNDBITE OF MUSIC)
BRUMFIEL: They sound different because the death of every star is different.
SODERBERG: Stars can die by running into each other, for example, like a car crash, or they can die by just running out of fuel. A lot of stars will do interesting things before they die, like pulsate or spin or get overheated.
BRUMFIEL: Each song eerily replays a star's dying moments as it explodes into a supernova, expands and cools into a cloud of gas and dust.
SODERBERG: It is eerie. At the end of the day, you end up with a supernova remnant. It's just a nebula of just gas.
BRUMFIEL: But these aren't only deaths. Supernova explosions release enormous quantities of elements like carbon, oxygen, nitrogen - elements we need. Elements we're made of.
SODERBERG: I mean, supernovae fertilize the universe. We wouldn't be here if it wasn't for supernovae.
BRUMFIEL: In a way, these funeral songs also announce a birth. Geoff Brumfiel, NPR News.
SIEGEL: We've posted some of Soderberg's music along with images of what's left behind when stars explode. It's all at our website, npr.org.