images

Aurora borealis in Alaska 01/2005

by

D.Anderson/Novapix

Reference

t-met01-11001

Date

2007-04-04

A very rare blue aurora photographed from the Homer, Alaska area. This type of aurora is seldom bright enough to be seen visually and are the result of direct sunlight striking already ionized nitrogen molocules in a process called "resonance scattering". This takes place high in the atmosphere during twilight. These types of aurora can reach 600 km or more in altitude. Jan 17 2005.