This image shows what is called a “sundog,” a naturally occurring reflection of light on the edge of a halo around that sun that is produced by fog in cold temperatures above water. (Image: Shawn Malone, Earth Science Picture of the Day)
This image taken over Lake Superior’s southern shore shows a reflection of light known as a “sundog” on the outer edges of a halo surrounding the sun.
Fog is created when cold air moves over water that is much warmer. Because of the cold, this fog often contains tiny ice crystals. The crystals can act as prisms, creating a 22-degree circle of light around the sun known as a “22-degree halo,” according to Earth Science Picture of the Day, which published this image.
The picture was taken by Shawn Malone on Jan. 17.
Because sundogs are red on their sunward side and gradually fade to white on the side facing away from the sun, it is apparent that this particular sundog is to the left of the sun. The sky is darker to the right of the sundog (the inner part of the 22-degree halo) because ice crystals can’t glint there, according to Earth Science Picture of the Day.
Earth Science Picture of the Day, a service of NASA’s Earth Science Division, collects and archives photographs that highlight natural phenomenon that help explain the way the processes of the world.