Why was There a Ring Around the Moon Last Night?
By: KARK 4 News
Updated: December 23, 2012
Viewers flooded social media Saturday night with a single question: what's that ring around the moon?
You may have noticed a circle around the moon around 7 p.m. Saturday. It's called a "moon ring" or "winter halo" and is usually caused by ice crystals that form high in the upper atmosphere.
The effect is similar to what you'd see in a rainbow: light from the moon passes through those crystals and is refracted.
More specifically -- as the moons light passes through crystals in Cirrus clouds, the light reflected. If the crystals are oriented correctly and positioned just right, then the result is a halo effect.
While someone may spot the halo in one area of Central Arkansas, someone 30 miles down the road may see something completely different depending on their positioning.
(Photo by Jeanette Hearnsberger Wicker)
