This striking ring around the Moon

 This striking ring around the Moon is a 22° lunar halo, an optical phenomenon formed when moonlight passes through millions of hexagonal ice crystals suspended in thin, high-altitude cirrostratus clouds. As the light is refracted at a precise angle, it creates a circular halo centered on the Moon, often showing subtle color separation—red on the inner edge, bluish tones outward.

The bright point near the center is a thin crescent Moon, not the source of the colors themselves; the halo’s hues come from wavelength-dependent refraction inside the ice crystals. Such halos are common in cold, stable upper-atmosphere conditions and can sometimes precede changing weather.