Earlier this month, NASA's Kepler Mission announced it had found 54 planets orbiting stars in so-called "habitable zones" in our galaxy, where the climate could be suitable for liquid water.
After the planets were found, NASA alerted the SETI Institute (Search for Extraterrestrial Intelligence) of their locations. The institutes's scientists started listening to those planets, and while they haven't heard any intelligent life yet, there's plenty of other noise to be heard in space.
Few people know more about sounds in space than University of Iowa physics professor Don Gurnett. He's been collecting sounds using instruments on satellites and space explorers for more than 40 years. Here's some of what he's heard.
SETI chief Jill Tarter says the Institute is not listening for the kind of sound you hear with your ears.
"What we're doing is using sensors that are sensitive to electromagnetic radiation," she says.
Electromagnetic radiation — like the energy in your microwave or from your reading lamp — is just another name for energy that travels in wave form. Radio signals are also a form of wave energy. So when SETI "listens" to the cosmos, the institute is actually receiving electromagnetic radiation.
"And then, just the way your radio does, that energy can be used to make audible sound," Tarter says.
