NASA spacecraft are constantly collecting and beaming back loads of data about our planet. The technology aboard these craft have given us amazing insights into how our world works and sometimes, they send back something that is not only scientifically significant, but also beautiful and awe-inspiring, like this time-lapse video of the light shows given by our planet.
The latest amazing offering is what NASA is calling "Earthsong." The agency's twin Radiation Belt Storm Probes have sent back a recording of the sounds that our planet makes, or more specifically, the electromagnetic radiation made by plasma waves in the radiation belts -- a phenomenon called chorus. The probes have delivered the clearest example of these sounds ever recorded since they're traveling right through that region and because the data is sampled in 16 bit, or the same as an audio CD.
"This is what the radiation belts would sound like to a human being if we had radio antennas for ears," says Craig Kletzing, whose team at the University of Iowa built the “EMFISIS” (Electric and Magnetic Field Instrument Suite and Integrated Science) receiver used to pick up the signals.
Chorus isn't made up of acoustic waves like those that travel through air here on the ground, but of radio waves that oscillate at acoustic frequencies, between 0 and 10 kHz. The receivers on the probes are specifically designed to pick up these waves.
You can click here to just hear the audio or watch the video below for the sounds and an explanation of the science behind them. If I didn't already know what it was, I'd easily mistake it for sounds of a rainforest.
The probes, which were just launched in August, could soon bring us these sounds in stereo.
“We have two spacecraft with two receivers, so a stereo recording is possible," Kletzing says. “One of the things we don't know is how broad the region is over which chorus occurs. The widely-separated ‘stereo capability’ of the Storm Probes will give us the ability to figure this out."