Recordings of the sounds of the Northern Lights, showing that this phenomenon is much more common than previously thought, and occurs even when not observed, were made by Unto Kalervo Laine – a former professor at Aalto University in Finland and a specialist in speech technologies. He presented a report at the recent EUROREGIO / BNAM2022 acoustics conference in Denmark. For many years, Laine has been studying the sounds associated with the Northern Lights. In 2016, he published information that the recordings of popping during aurora borealis were related to temperature profiles recorded by the Finnish Meteorological Institute (FMI). These data not only demonstrate that auroras can be associated with sounds, but also confirm Lane’s own theory that these sounds result from electrical discharges in the temperature inversion layer at a height of about 70 meters above the ground. New examples of northern lights were recorded at night near the village of Fiskars. Although the glow itself was not visible at the time, Lane’s recording captured hundreds of “auroral sounds.” When the records were compared with FMI geomagnetic activity measurements, an obvious strong correlation was found. All 60 best candidate sounds were associated with changes in the geomagnetic field. “Using geomagnetic data that has been measured independently, it is possible to predict when aurora borealis sounds will be 90% accurate,” says Laine. His statistical analysis suggests an unambiguous causal relationship between geomagnetic oscillations and auroras.
At the end of March 2022, NASA experts shared plans to launch two rockets at an altitude of over 200 km directly into the northern lights to study in detail the processes of energy exchange between the Earth and outer space. This was reported by the NASA portal. Radiance is born on the border between the electrically neutral atmosphere around the planet and the interplanetary space filled with charged particles from the plasma of the solar wind, interacting with the geomagnetic field. The resulting luminescent glow from below looks like huge canvases of different colors and dancing light waves. But the picture is not limited to the earth’s spectacle – the interactions between the particles excite wider boundary layers of the atmosphere, and it is the impact of charged particles on these upper layers that interests NASA. The agency is preparing for today in Alaska the INCAA mission – Ionic neutral compound during active radiance. There is no clear boundary of the layer where the neutral gas ends and the plasma begins – there is a large boundary zone where the two types of particles mix, which from time to time collide and emit photons of different wavelengths. The color of the “sails” depends on the composition of atmospheric molecules: oxygen gives a pale green or red light, nitrogen – reddish or purple. The first rocket is planned to emit harmless vapor indicators – colored chemicals similar to those used in fireworks – before reaching a maximum altitude of 300 km. The vapor indicators will create visible clouds that researchers can observe from the ground, thus tracking air currents near the glow. The second rocket, which will be launched shortly after the first, reaching a height of about 200 km, will measure the temperature and density of plasma in and around the glow.
