NASA craft picks up 'alien folk music'

NASA / NASA's Cassini space probe sent to explore Saturn found musical radio signals as it sped past Jupiter, above with its moon Ganymede.

The unmanned Cassini space probe that NASA has sent to explore Saturn has found something strange as it sped past Jupiter: Musical radio signals.

It's not great music, mind you. But the eerie sound does have a tune of sorts, and kind of a catchy rhythm. It reminds Citizen columnist and trumpet player Charles Gordon of I've Been Working on the Railroad.

The sound itself is breathy, ghostly, definitely a wind instrument.

And anyone with Internet access can find a 10-second recording of it on CNN's technology Web site http://CNN.com/2000/TECH/space/12/19/jupiter.sounds.

The radio waves come from the "solar wind," radiation from the sun that rushes outward through our solar system. When this radiation runs into the electrically charged particles in Jupiter's upper atmosphere, the collision sends out a low-frequency radio waves.

"Sounds like alien folk music," CNN says.

At the Canada Museum of Science and Technology in Ottawa, Randall Brooks is reminded more of music from Alouette, Canada's first satellite, launched more than 30 years ago.

"I have a whole pile of tapes in the (museum) collection of these taken by Alouette through the years, which were called whistlers, because they would start low and go to a higher frequency," said Mr. Brooks.

Mr. Brooks is the museum's space curator.

"Cassini is picking up these as low-frequency radio waves (near Jupiter) which they are then converting to audible sound," he said.

Cassini, at $3.4 billion U.S., is the most expensive object in space. It was also the most controversial space probe, fueled by more than 30 kilograms of plutonium to keep it flying at high speed until it reaches Saturn in 2004. It will orbit Saturn and feed back data until 2008 about the planet and one of its moons, Titan.

The CNN site also has a link that lets people listen to radio waves from a meteor entering our own atmosphere. It sounds like a clear whistle, and is caused by the high-speed bit of space debris actually tearing the electrons off atoms in our air, and that creates a weak radio signal for a second or two.