Why is there a ring around the sun or moon?

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RICHMOND, Va. — While it doesn’t happen every day, we are occasionally treated to a funky sky phenomenon of a halo around the sun or moon.

This ring is caused by cirrostratus clouds, which are made of ice crystals.  They are found above 20,000 feet.  They can get quite thick, but sun or moon light can be seen through them.

Image courtesy of NASA

This light is refracted through the ice crystals, and this causes the halo.  At times, the clouds can be very thin and hardly visible until the halo is shown.

We often see cirrostratus clouds increasing ahead of a front or storm system.  Thursday afternoon’s halo was caused by moisture being thrown into our area by the remnants of Tropical Depression Cindy.