Aurora over Alaska
Now I know why I want to go back. Nothing like seeing an image like this after being on call for an entire weekend.
Aurora Over Alaska
Credit & Copyright: Paul Alsop
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.