Audio recording captures a “thunderclap” from recent display in Finland
Dr. Tony Philips writes:
For centuries, people inside the Arctic Circle have reported hearing strange hissing and popping sounds under the Northern Lights. Evidence is mounting that at least some those auroral sounds are real. A researcher in southern Finland recorded some during a recent G1-class geomagnetic storm–the latest in a series of detections by the long-running Auroral Acoustics Project.
On Oct. 7th, a solar wind stream hit Earth’s magnetic field, sparking a G1-class geomagnetic storm. In southern Finland, the night sky turned green as energetic particles rained down on the upper atmosphere. But there was more to the show than beautiful lights.
“The storm also produced a number of distinctive sounds including crackles and claps,” reports Prof. Emeritus Unto K. Laine of Finland’s Aalto University. “Here is a recording of one of the strongest sounds of the night–a sharp clap.” Click to listen:
More samples, images, graphs and the full story at spaceweather.com