Spooky sound from 'cosmic fireball' hitting Earth

Sound engineer Unto Laine from Aalto University in Finland was trying to capture strange sounds coming from the sky one night a terrifying CME plasma ball "landed" into Earth's magnetosphere.

CME events set Earth's sky ablaze in colorful auroras.

CMEs usually follow geomagnetic storms (solar storms), which are a stream of high-energy plasma. If it collided with Earth's magnetosphere, particles from the solar wind would be accelerated along magnetic lines of force to high latitudes, "raining" into the upper atmosphere and interacting with the particles. in the atmosphere, creating a magical aurora.

Strange sounds like slamming, crackling from the sky, sometimes like cracking, impact sounds were recorded by special equipment set up near the village of Fiskars - Finland.

The data is cross-referenced with geomagnetic activities recorded by the Finnish Meteorological Institute, and compared with other acoustic data to filter out noise. They eventually filtered out about 60 strange sounds related to changes in the Earth's magnetic field with 90% accuracy.

In particular, those are sounds that are completely audible to the human ear.

"The sounds are much more common than people think, but when people hear them without seeing the aurora, they think it's just the crack of ice or maybe a dog or some other animals," author Unto Laine told Science Alert.

The authors add that the sound is usually only present during the "wildest" auroras, and can sometimes become as powerful as a waterfall.

The research was recently presented at the UROREGIO/BNAM2022 Acoustics Conference.