<Table> <Tr> <Td> </Td> <Td> This article needs additional citations for verification . Please help improve this article by adding citations to reliable sources . Unsourced material may be challenged and removed . (September 2014) (Learn how and when to remove this template message) </Td> </Tr> </Table> <Tr> <Td> </Td> <Td> This article needs additional citations for verification . Please help improve this article by adding citations to reliable sources . Unsourced material may be challenged and removed . (September 2014) (Learn how and when to remove this template message) </Td> </Tr> <P> Halo (from Greek ἅλως, halōs) is the name for a family of optical phenomena produced by light interacting with ice crystals suspended in the atmosphere . Halos can have many forms, ranging from colored or white rings to arcs and spots in the sky . Many of these are near the Sun or Moon, but others occur elsewhere or even in the opposite part of the sky . Among the best known halo types are the circular halo (properly called the 22 ° halo), light pillars and sun dogs, but there are many more; some of them fairly common, others (extremely) rare . </P> <P> The ice crystals responsible for halos are typically suspended in cirrus or cirrostratus clouds high (5--10 km, or 3--6 miles) in the upper troposphere, but in cold weather they can also float near the ground, in which case they are referred to as diamond dust . The particular shape and orientation of the crystals are responsible for the type of halo observed . Light is reflected and refracted by the ice crystals and may split up into colors because of dispersion . The crystals behave like prisms and mirrors, refracting and reflecting light between their faces, sending shafts of light in particular directions . </P>

Sun's halo is produced by the refraction of light in