In an August 24th post on Short Sharp Science, David Cohen, New Scientist features editor, speaks of the strange missions on which New Scientist writers can be sent. He goes on to tell the story of how one morning early this August he got up at the crack of dawn and drove down Death Valley highway to the Dumont Dunes (CA) – “one of only 33 known sites worldwide where dunes have been known to sing.” His mission: to hear the singing. Once there

I sat down, dug my hands into the sand and started inching down the slope, feet-first like a giant caterpillar. Nothing happened. Sure, sand was moving, but all I could hear were gentle burping noises emanating from the sand beneath my feet with every push. I checked no-one was watching (imagine the humiliation of coming all this way and not hearing a thing) then dug my arms deeper into the sand and sped up. This sucker was going to sing if I had to dig up half the dune.

Thankfully, it didn’t come to that. I had shuffled just a metre further down the slope with a good sand avalanche going, when it began. The burping sound suddenly transformed into a low growl, as if a thousand yogis hidden beneath the dune had started chanting “Om”. It felt like the ground itself was vibrating with the sound and it grew louder and louder.

You can listen to the sound on the video below. There are different opinions about what makes the dunes sing. Nathalie Vriend and Melany Hunt, at the California institute of Technology, Pasadena, have been working on an explanation. In a paper published this week in Geophysical Research Letters, they outline their theory, “suggesting that sand acts like a wave guide in which individual vibrations constructively interfere to produce a louder tone. The surface of a dune then amplifies the vibrations, like a giant loudspeaker.”

But two French researchers, Stéphane Douady and his former PhD student Bruno Andreotti, have competing theories about singing sand dunes. Vriend and Hunt’s theory refutes theirs… so let’s just say the music of the dunes is a subject still up in the air.

With thanks to Geoff Manaugh and BLDG BLOG.