Cosmic radio waves mimic chirping of alien birds

Twin spacecraft have captured the clearest sounds yet from Earth's radiation belts. NASA's Van Allen Probes have been exploring the hostile radiation belts surrounding Earth for just three months.

Scientists said Tuesday these waves can provide an energy boost to radiation belt particles, somewhat like ocean waves can propel a surfer on Earth. What's more, these so-called chorus waves operate in the same frequency as human hearing so they can be heard.

While the chorus has been audible even before the Space Age the clarity of these measurements is "really quite striking," Kletzing said. Initial findings show the outer radiation belt to be much more dynamic and rapidly changing than anticipated, said the University of Colorado's Daniel Baker, principal investigator for the electron proton telescope on each probe.

The Van Allen probes were launched from Cape Canaveral on Aug. 30. They were named after the late University of Iowa astrophysicist James Van Allen, who discovered the radiation belts that bear his name a half-century ago.