A spectacular moondog formed in
the sky over Fairbanks, Alaska,
on the evening of March 17,
2003. A moondog, or
paraselene, forms when moonlight
combines with ice crystals high
in the Earth's atmosphere.
It appears brighter and more
colorful than the accompanying
ring around the moon because the
ice crystals there are probably
larger. The star to the
left of the moondog's "tail" is
Arcturus, and a faint reddish
aurora can be seen behind the
cirrus clouds above the moon.