Original URL: http://www.theregister.co.uk/2012/07/10/noisy_northern_lights/

Finnish boffins don tinfoil hats, admit Northern Lights are noisy

Aurora borealis makes a 'clapping sound', claim researchers

By Brid-Aine Parnell

Posted in Science, 10th July 2012 15:33 GMT

Cranks who claimed that the aurora borealis makes a noise when it lights up the Northern sky have been proven right by science.

Boffins from Aalto University in Finland recorded the 'clapping' sounds of the Northern Lights back in 2004, but only discovered the noises when they switched the recording from DV tapes to disc.

Just to check they were right, the researchers then put three microphones in three different locations during the phenomenon to record the auroral sounds again.

The researchers realised that the reason scientists had thought the people claiming the Northern Lights made noises were a few fries short of a Happy Meal was that the sounds were made quite close to the ground.

"Our research proved that, during the occurrence of the Northern Lights, people can hear natural auroral sounds related to what they see. In the past, researchers thought that the aurora borealis was too far away for people to hear the sounds it made," Prof Unto Laine said in a canned statement.

As well as clapping, the aurora borealis also makes crackles and muffled bangs that are difficult to hear if there's any background noise, say the researchers.

While the researchers believe sounds are caused by the same energy particles from the Sun that create the Northern Lights, they can't say too much more about them than that. There are many different noises and they don't always happen when the Northern Lights appear, so the boffins suspect there's more than one thing going on, but they don't know for sure yet.

The study will be published in the proceedings of the 19th International Congress on Sound and Vibration, a conference in Lithuania that will go on until Thursday. ®