Le aurore boreali in Islanda

Le meravigliose foto scattate una settimana fa nei cieli del parco di, con la luna piena

SNAEFELLSNES, ICELAND - FEBRUARY 18: EXCLUSIVE. The Aurora Borealis over Fjord Grundarfjorour on February 18, 2011 in Snaefellsnes, Iceland. These incredible aurora images may fool you into thinking they were taken in broad daylight. Kerstin Langenberger spent 300 hours chasing The Aurora Borealis by full moon to capture this rarely seen set of images. They show how the mystically beautiful landscape of the untouched UNESCO World Heritage Site of Thingvellir National Park was cloaked in a multicoloured explosion of light. The curtains of green and purple light make the brightly lit snow capped mountains and crystal clear lakes look like they are part of an alien world, haunted by ghostly mirages. Aurora's are caused by charged particles being blasted through space from the sun. These are attracted to the Earth's magnetic field at the North and South poles. The energy released by the particles striking the atmosphere of the Earth at about 150 km above the surface of our planet causes the jaw-dropping displays of light. (Photo by Kerstin Langenberger / Barcroft Media / Getty Images)
SNAEFELLSNES, ICELAND - FEBRUARY 18: EXCLUSIVE. The Aurora Borealis over Fjord Grundarfjorour on February 18, 2011 in Snaefellsnes, Iceland. These incredible aurora images may fool you into thinking they were taken in broad daylight. Kerstin Langenberger spent 300 hours chasing The Aurora Borealis by full moon to capture this rarely seen set of images. They show how the mystically beautiful landscape of the untouched UNESCO World Heritage Site of Thingvellir National Park was cloaked in a multicoloured explosion of light. The curtains of green and purple light make the brightly lit snow capped mountains and crystal clear lakes look like they are part of an alien world, haunted by ghostly mirages. Aurora's are caused by charged particles being blasted through space from the sun. These are attracted to the Earth's magnetic field at the North and South poles. The energy released by the particles striking the atmosphere of the Earth at about 150 km above the surface of our planet causes the jaw-dropping displays of light. (Photo by Kerstin Langenberger / Barcroft Media / Getty Images)

Queste fotografie sono state scattate tra il marzo 2010 e la settimana scorsa. In gran parte nel Parco nazionale di Þingvellir in Islanda, in una notte (già, una notte) di luna piena, luminosissima: altre vengono da diversi luoghi dell’Islanda e della Norvegia. Le ha scattate tutte la fotografa Kerstin Langenberger alle luci dell’aurora boreale, fenomeno così descritto da Wikipedia:

Il fenomeno è causato dall’interazione di particelle cariche (protoni ed elettroni) di origine solare (vento solare) con la ionosfera terrestre (atmosfera tra i 100-500 km). Tali particelle eccitano gli atomi dell’atmosfera che diseccitandosi in seguito emettono luce di varie lunghezze d’onda. A causa della geometria del campo magnetico terrestre, le aurore sono visibili in due ristrette fasce attorno ai poli magnetici della terra, dette ovali aurorali. Le aurore visibili ad occhio nudo sono prodotte dagli elettroni, mentre quelle di protoni possono essere osservate solo con l’ausilio di particolari strumenti, sia da terra sia dallo spazio. L’aurora polare è visibile, spesso, anche in zone meno vicine ai poli, come la Scozia, o molte zone dell’Australia.