Listening to the Stars
Originally published in the New York Times 1/31/2011
By DENNIS OVERBYE
The search for distant planets starts with the vibrations of their stars, and in those vibrations lies a kind of music.
“We only know the planet as well as we know the star,” said Natalie Batalha, an astronomer from San Jose State University who works on NASA’s planet-searching satellite Kepler. To that end, Kepler listens to the internal vibrations of stars, gleaning crucial information on their size and structure.
By speeding up this data and transforming it into sound waves, Kepler’s astronomers have produced a sort of iTunes sampler of the cosmos, individual stars banging and whistling.
“Some of these are music only the Borg could love,” said Jon Jenkins, a Kepler data analyst from the SETI Institute in Mountain View, Calif., referring to the cybernetic foes from the “Star Trek” series. Dr. Jenkins made the recordings presented here.
Kepler monitors the light of 156,000 stars, checking for dips in intensity caused when their planets, if they have any, pass in front of them. It also records high-frequency variations in stars’ light caused by vibrations or “starquakes” in the stars themselves, from which astronomers practicing the science of asteroseismology can deduce the age and size of the star.
By knowing how big the star really is, and the dips in light from the planetary crossings, astronomers can measure the exact size of any planet.
In these audio clips, several weeks’ worth of Kepler measurements of a star have been compressed into a few seconds.
Kepler 10b is the first rocky planet to be discovered by Kepler. The first audio contains only the vibrations of Kepler 10b’s star. The next audio clip has the sound of the planet going by as a “wump wump wump.”
KIC1268220 is an eclipsing binary, in which a pair of stars pass in front of each other, producing a bass thumping of eclipses along with a “whistling forest” of stellar vibrations, in the words of Dr. Jenkins.
KIC12253350 is an unusual star. On a graph, its oscillations follow a heart-shaped envelope. The Kepler astrophysicists do not understand why, but they liked it so much that they put the heart-shaped oscillations on a T-shirt with a quotation about the cosmos by Carl Sagan: “For such small creatures such as we the vastness is bearable only through love.”