Sub-Sundog

Sub-Sundog

Next week's Thanksgiving is the biggest travel holiday of the year in the United States. Millions of people board airplanes and fly long hours to visit friends and family. Dreading the trip? Think of it as a sky watching opportunity. There are some things you can see only through the window of an airplane--like this:

"In the tops of the clouds, I saw a bright reflection of the sun flanked by rainbow-colored sundogs," says Alex Ruege, who snapped the picture on November 14th while he was flying over Phoenix, Arizona.
Atmospheric optics expert Les Cowley explains the apparition: "Look down from the sunny side of an aircraft and you will often see a dazzling reflection of the sun in the clouds. This is a subsun, formed by millions of plate shaped ice crystals acting as mirrors. Sometimes the subsun is flanked by two colorful sub-sundogs. How do they form?  Sunlight nearly always bounces up and down inside the thin ice plates before it can emerge.  An even number of bounces make a sundog.  An odd number makes the sub-sundog.  When you see halos always check out the opposite direction – you might see even rarer sights!"