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YLLÄS TIMES


NEWS FROM YLLÄS 2017 Shhh, can you hear the Northern Lights?


Te Northern Lights are breathtakingly beautiful, but did you know that during a hard frost and clear weather, you can even hear them? Several years ago, a research team from


Finland’s Aalto University demonstrated that the Northern Lights produce sounds that originate near the Earth’s surface at about 70 metres altitude. Tis research work was continued further and resulted in an explanation of how these sounds are produced. According to a new inversion hypothesis


published last summer, the popping and crackling sounds occur when a related geomagnetic storm activates the charges


that have accumulated in the atmosphere’s inversion layer, thus causing them to di- scharge. Sounds technical, doesn’t it? Research


professor Unto K. Laine explains it himself: “Normally, the higher the altitude, the


lower the temperature will be. However, in a hard frost and generally calm weather during the evening and night, the coldest point is near the earth’s surface, and the air above it is warmer. Tis warm air does not mix but instead rises up until reaching an impenetrable colder layer carrying nega- tive charges from the ground.” “Likewise positive charges accumulate in the colder air above this isolating layer


or ‘lid’. A geomagnetic storm finally cau- ses these charges to discharge, producing measurable magnetic pulses with popping and crackling sounds.” As the basis of his research, professor


Laine recorded the sounds in March 2013. Te Auroral Acoustics research project entitled “A progress report with a new hypothesis,” was presented on 22 June at the Baltic-Nordic Acoustic Meeting in Stockholm. What do you think, could you too hear


the sounds of the Northern Lights? Why not tune in to the Northern Light frequen- cies and set off into the frosty night to do your own field research!


Grandeur from the “Northern Gate” to the corona


Te basic form of an aurora vaguely resembles a rainbow and can be seen as an arc from east to west across the northern sky. In old mythology, the Northern Lights were called the ‘Northern Gate’. An active aurora changes its shape rapidly, and typical colours are green-tinged yellow and violet. Te Northern Lights corona can be seen when the


aurora formations are directly overhead. Ten the ribbon-like aurora shapes flowing from bottom to top appear to join up at the celestial pole. Tis is due to aerial perspective, as the aurora ‘curtains’ form a vertical structure that is observed by loo- king upwards. Active auroras usually die down in the early hours


of the morning, aſter blazing almost non-stop since late evening. By then, the auroras might still spasm in flickering bursts before dying down completely. Tey oſten fill the skies with gossamer-like shapes.


Source: Finnish Meteorological Institute


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you find Ylläs on the map?


Well, raise your right arm...


Now you are the map of Finland and Ylläs is here.


YLLÄS TIMES NEWS FROM YLLÄS


Published by: Print run:


Luova Media Oy, publisher of the finnish local paper Kuukkeli.


6 000 copies


Printed by: Translator:


On the cover:


Suomalainen Lehtipaino Oy, Kajaani David Cox


Over 200 entries for Ylläs Reindeer Cup race.


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