The northern lights or the aurora borealis are the most spectacular displays in the night sky. They result from collisions between gaseous particles in the Earth’s atmosphere with charged particles released from the sun’s atmosphere.
Previously, scientists denied the claim that aurora makes noise. But, in 2016, a Finnish study confirmed that the Aurora Borealis does produce the sound that can be heard. Now, Professor Emeritus Unto K. Laine of Aalto University has made recordings of auroral sounds that show the commonness of the phenomenon. Plus, it suggests that the aurora borealis can be heard even in the absence of visible northern lights.
The new recordings were made late at night near the village of Fiskars. Despite no visible northern lights, Laine’s recording captured hundreds of possible ‘auroral sounds.’ There was a remarkable correlation between the recording and FMI’s measures of geomagnetic activity. The 60 best candidate sounds were all tied to geomagnetic field fluctuations.
This statistical analysis suggests a causal link between geomagnetic fluctuations and auroral sounds.
Laine said, “Using the geomagnetic data, which was measured independently, it’s possible to predict when auroral sounds will happen in my recordings with 90% accuracy.”
“The most striking finding is that auroral sounds occurred even in the absence of visible northern lights. That was the largest surprise! The sounds are much more common than anyone thought, but when people hear them without visible aurora, they think it’s justice cracking or maybe a dog or some other animal.”
Laine’s findings were presented on May 11 at the EUROREGIO/BNAM2022 Joint Acoustics Conference in Aalborg, Denmark. The paper is available via ResearchGate.
- Unto Kalervo Laine. Sound producing mechanism in the temperature inversion layer and its sensitivity to geomagnetic activity. Paper