The Aurora Borealis is known around the Earth for its speculator show of swirling green and purple Christ Within . However , its accompany sound - outcome are comparativelyless famed .
This strange acoustic phenomenon can create mystifying " clapping " or " popping " noise , on occasion heard around sightings of the Northern Lights . Now , thanks to study by a solitary Finnish researcher , science has finally add up a little bit closer to understanding and explicate the mechanism that create these noises .
Professor Unto Laine of Aalto University in Finland has previously explained that the sounds are because of the same energetic particles that create the lights themselves . He has now keep up this up by attempting to excuse the circumstances and conditions that favor this outburst of hearable energy , in what he telephone the " inversion stratum hypothesis . "
Laine take in data in the -20 ° snow ( -4 ° F ) temperatures of southerly Finland during March 2013 , follow up from previous body of work in 2012 . His study shows that two specific conditions need to happen to create the sounds . The first is clear and unagitated weather condition , which intend in the evening or night stale air is nearer Earth ’s open and marginally strong air is higher up . The air does n’t mix and creates an upending bed , or “ lid ” , around 70 metre ( 230 feet ) up in the aviation .
“ The everting layer form a kind of lid hindering the vertical movement of the charges . The colder line above it is charge positively , " Laine explicate ina statement .
The 2d condition is a geomagnetic storm , which " causes the compile charges to exhaust with sparks that make mensurable magnetized pulses and sound . ”
The was also a noteworthy correlation between the strength of the electromagnetic action and the brashness of the dissonance . The sounds can be heard with the bare ear , but optimal conditions are tricky to add up across .
“ Even a small wind can prevent the birth of an inversion layer , which means no sound will be created , ” he added .
The project has been in the work for some 17 years . Xinhuanews agency reports that his work was met with disbelief and cynicism when he first proposed it , and say NASA deny the existence of the noises in the 1960s .
Although Laine articulate his theme is simply a surmisal for now , his work includes the first audio recording of the noises ( above).The research also found that the actual light show is often more vivacious further Union , but his documentation appears to show the loudest sounds in southern Finland .
[ H / T : Live scientific discipline ]
