Sun dogs over Detroit, MI
© WXYZ
Something unusual in the sky caught the eyes of many across metro Detroit Sunday afternoon.

Our viewers were sending in photos of an atmospheric phenomena asking, "what is this?" or referring to them as "little rainbows".

What you see in the photos are called "sun dogs". One to the left of the sun, and one to the right of the sun. The phenomenon occurs when sun light hits ice crystals high up in the atmosphere. That light is refracted through the crystals, and what we see is the scattering of the light. Usually sun dogs are accompanied by a 22° halo around the sun, which is also a refraction of light through ice crystals. These are common ahead of warm fronts, as high-level clouds slowly move in at high altitudes.

Some viewers also caught photos of what looks like an upside-down rainbow. This is called a "circumzenithal arc", and is also the result of sun light passing through ice crystals. The only primary difference between arcs and sun dogs are the shape of the ice crystals.