Astronomy Picture of the Day
    


Aurora Over Alaska
<< Yesterday 6.10.2010 Tomorrow >>
Aurora Over Alaska
Credit & Copyright: Paul Aslop
Explanation: Are those green clouds or aurora? Photographed above two weeks ago, puffy green aurora help the Moon illuminate the serene Willow Lake and the snowy Wrangell and Saint Elias Mountains in eastern Alaska, USA. Although auroras might first appear to be moonlit clouds, they only add light to the sky and do not block background stars from view. Called northern lights in the northern hemisphere, auroras are caused by collisions between charged particles from the magnetosphere and air molecules high in the Earth's atmosphere. If viewed from space, auroras can be seen to glow in X-ray and ultraviolet light as well. Predictable auroras likely occur a few days after a powerful magnetic event has been seen on the Sun.

January
February
March
April
May
June
July
August
September
October
November
December
 < October 2010  >
Mo Tu We Th Fr Sa Su




123
45678910
11121314151617
18192021222324
25262728293031
Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (USRA)
NASA Web Site Statements, Warnings, and Disclaimers
NASA Official: Jay Norris. Specific rights apply.
A service of: LHEA at NASA / GSFC
& Michigan Tech. U.

Based on Astronomy Picture Of the Day

Publications with keywords: aurora - star trail - magnetic field
Publications with words: aurora - star trail - magnetic field
See also:
All publications on this topic >>