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.

March 4, 1998

Aurora Over Alaska
Credit & Copyright: D. Hutchinson

Explanation: Higher than the highest mountain, higher than the highest airplane, lies the realm of the aurora. Aurora rarely reach below 60 kilometres, and can range up to 1000 kilometres. Aurora light results from solar 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 photograph was taken in January in Alaska and shows a spectacular aurora borealis above a frozen landscape which includes spruce trees and the photographer's truck. The picture had to be taken quickly as the temperature was below -40 degrees.

Tomorrow's picture: Hunter, Dog, Bull, Canary

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Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (USRA)
NASA Technical Rep.: Jay Norris. Specific rights apply.
A service of: LHEA at NASA/ GSFC
&: Michigan Tech. U.