The Rosetta mission captures this 'song' from Comet 67P Churyumov-Gerasimenko.
This is what a comet sounds like. Or one particular, increasingly famous comet, anyway.
We've slowly been learning more and more about Comet 67P/Churyumov-Gerasimenko as the European Space Agency's Rosetta probe gets ever closer to its space rock prey. We recently found out what it smells like: space farts. And now we know that it's "singing" this percussive little ditty as it goes. As one commenter put it, it kind of sounds like a dolphin.
ESA announced the observation on its Rosetta blog, and explained that the "music" is produced "in the form of oscillations in the magnetic field in the comet's environment" picked up by the mission's magnetometer experiment from a distance of around 100 km. These oscillations would actually be way too low for human ears to hear, so they've increased the frequencies by around a factor of 10,000.
But for every new thing we learn about Comet 67P/C-G, we're reminded of quite how much is left to discover. Quite how the oscillations are caused is as yet unknown (the ESA researchers reckon it must have something to do with the comet's activity whereby it releases particles into space).
It's this remaining mystery around this comet, and comets in general, that ESA's current mission hopes to shed some light on. Tomorrow, the Philae lander will descend from the Rosetta spacecraft onto the surface of the comet in a major milestone for comet exploration. It's already sniffed, heard, and snapped photos of the comet; next it will actually touch it.