I made the comment that the Moon was getting too much attention lately so the Sun had to do something spectacular -- and it did. Shortly after noon today, a circle of light formed around the sun. No, it's not a portal to another dimension, as someone joked on Facebook, but rather the bending of light waves as they pass through ice crystals.
Known as a "Sun Halo," it's formed as the suns rays are bent while entering cirrus clouds passing high up in the sky. Although we have cirrus clouds moving overhead quite regularly, it's the way those ice crystals are positioned that make the difference in creating this interesting phenomena.
These clouds contain millions of tiny ice crystals. The halos you see are caused by both refraction, or splitting of light, and also by reflection, or glints of light from these ice crystals. The crystals have to be oriented and positioned just so with respect to your eye, in order for the halo to appear.
The light is refracted and then reflected at 22 degrees, to allow the halo to form. Thus the name "22 degree halo."
The old saying goes, "Ring around the moon it will rain soon." There is some truth to this, because, cirrus clouds usually move out ahead of storms developing.