Explanation: Higher than the highest building, higher than the highest mountain, higher than the highest airplane, 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 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. The above wide angle image, horizontally compressed, captured an unexpected auroral display that stretched across the sky one month ago over eastern Norway.

Best Short Astronomy Videos: APOD editor to speak in New York City on Friday, January 6

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