Scientists tune in the song of the planet.
This is Sandra Tsing Loh with The Loh Down on Science
and a greeting from deepest space!
Sound: Auroral Kilometric Radiation
But what is that? Message from a passing UFO? Squeaky door on the space shuttle? The Klingon Top 40?
Au contraire! It's called Auroral Kilometric Radiation--AKR--and the source is our very own Earth.
High above us, electromagnetic particles crash into Earth's magnetic field. This produces radio waves ten thousand times stronger than military radar signals. Scientists have studied about twelve thousand of these AKR bursts.
They shoot out into space in a narrow beam. The chirps and whistles could easily be heard by a passing space ship--one with a good enough car stereo to pick them up, that is.
So, why don't we hear the broadcast? Because AKR is blocked by Earth's ionosphere. Otherwise, the signals would garble radio reception all over the planet.
Scientists hope that, with bigger radio telescopes, they can pick up on AKR coming from Jupiter, Saturn and even planets beyond our solar system. Think of the movie possibilities! Two words: Contact 2.
Paging Jodie Foster.