Astronomy Picture of the Day

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2014 October 14
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Auroral Corona over Norway
Image Credit & Copyright: Harald Albrigtsen

Explanation: Higher than the highest mountain lies the realm of the aurora. Auroras rarely reach below 60 kilometers, and can range up to 1000 kilometers. Aurora light results from energetic electrons and protons striking atoms and molecules in the Earth's atmosphere. Somewhat uncommon, an auroral corona appears as a center point for a surrounding display and may occur when an aurora develops directly overhead, or when auroral rays are pointed nearly toward the observer. This picturesque but brief green and purple aurora exhibition occurred last month high above Kvaløya, Tromsø, Norway. The Sessøyfjorden fjord runs through the foreground, while numerous stars are visible far in the distance.

APOD Wall Calendar: Land and Skyscapes
Tomorrow's picture: titan's thing

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