It's a question that has puzzled observers for centuries: do the fantastic green and crimson light displays of the aurora borealis produce any discernible sound?
Conjured by the interaction of solar particles with gas molecules in Earth's atmosphere, the aurora generally occurs near Earth's poles, where the magnetic field is strongest. Reports of the aurora making a noise, however, are rare — and were historically dismissed by scientists. But a Finnish study in 2016 claimed to have finally confirmed that the northern lights really do produce sound audible to the human ear. A recording made by one of the researchers involved in the study even claimed to have captured the sound made by the captivating lights 70 meters above ground level. Still, the mechanism behind the sound remains somewhat mysterious, as are the conditions that must be met for the sound to be heard. My recent research takes a look over historic reports of auroral sound to understand the methods of investigating this elusive phenomenon and the process of establishing whether reported sounds were objective, illusory or imaginary.
Historic claims
Auroral noise was the subject of particularly lively debate in the first decades of the 20th century, when accounts from settlements across northern latitudes reported that sound sometimes accompanied the mesmerizing light displays in their skies. Witnesses told of a quiet, almost imperceptible crackling, whooshing or whizzing noise during particularly violent northern lights displays. In the early 1930s, for instance, personal testimonies started flooding into The Shetland News, the weekly newspaper of the subarctic Shetland Islands, likening the sound of the northern lights to "rustling silk" or "two planks meeting flat ways." Read more...
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