Auroral crackling sounds are related to the electromagnetic resonances of the Earth
The study is a continuation of a hypothesis that Unto K. Laine, Professor Emeritus, published three years ago on the origin of the sounds heard during the displays of the Northern Lights. His theory postulated that the sounds are generated when a magnetic storm causes charges in the temperature inversion layer of the lower atmosphere, to be discharged at an altitude of 70 to 80 metres.
A recent research paper presented by Laine at the ICSV26 congress in Montreal provides a more detailed account of the sound generation. According to this study, when the Northern Lights occur, the spectrum of the temporal envelope of the crackling noise (or in other words, the rapid changes in the sound amplitude) contain frequencies of the Schumann resonances.
The Schumann resonances refer to the low-frequency electromagnetic resonances occurring around the Earth, the strongest of them being below 50 Hz. Laine has now observed that these resonances generated similar rhythmic structures in all the measured crackling sounds.
’Previous international research has shown that a geomagnetic storm occurring during the Northern Lights reinforces the Schumann resonances. For the first time, such resonances have been found to activate the sound generation mechanism in the temperature inversion layer at altitudes of between 70 to 80 metres where the accumulated electric charges give rise to corona discharges and crackling sounds. In addition to the nine lowest Schumann resonances, the spectra also include their difference and sum frequencies or in other words, distortion components. This non-linearity also lends support to the hypothesis of auroral sounds generation,’ Laine says.
The research material consisted of 25 sound events measured on the ground in September 2001 and in March 2012 in Southern Finland, during the display of active Northern Lights. Although the measurements were conducted at different locations using various equipment, the results nevertheless point to the same direction.
The results will be published today (10 July) at the ICSV26 congress in Montreal, which brings together more than 2,000 researchers in acoustics from around the globe.
Further information:
Unto K. Laine, Professor Emeritus
Read more news
The study voucher has been introduced – study 30 ECTS credits of Open University courses free of charge
The study voucher is a payment instrument that you can use to pay for open studies in Finnish and Swedish at Finnish higher education institutions.International educational project at Aalto University funded by the TFK Programme
The Bio-Design for Low Carbon Architecture (Bio-LCArch) project is a collaborative initiative between Aalto University in Finland and Beijing Jiaotong University in China, geared toward demonstrating how bio-based materials can facilitate the construction industry's transition to net-zero emissions.
Coming soon, ARTEFAKTI26 (3.-9.9.2026)
ARTEFAKTI returns for the fourth year to Helsinki Design Week from the 3rd to 9th of September 2026 at Puristamo hall in Kaapelitehdas