What is that huge beautiful ring of light around the moon called?
It is due to the scattering of light by high clouds made from ice crystals. These clouds (cirrus) are thin enough to allow light through, but due to the difference in distance between the clouds and the Moon, the ice scatters the light and makes it look like a ring of light around the Moon. It also happens around the Sun, but due to the strong intensity of the sunlight, it is hard or impossible to actually see it visually.
