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.
2009 February 1
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.
2009 February 1
Explanation: Higher than highest communications tower, higher than highest mountain, higher than highest airplane, lies the realm of the aurora. Aurorae rarely reach below 60 kilometres, and can range up to 1000 kilometres. Aurora light results from energetic electrons and protons striking molecules in the Earth's atmosphere. Frequently, when viewed from space, a complete aurora will appear as a circle around one of the Earth's magnetic poles. This particularly rare purple auroral corona occurred in 2004 high above Harstad, Norway.
Authors & editors:
Robert Nemiroff
(MTU) &
Jerry Bonnell (UMCP)
NASA Official: Phillip Newman
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