<Tr> <Th> Designations </Th> <Td> NGC 1976, M42, LBN 974, Sharpless 281 </Td> </Tr> <Tr> <Td_colspan="2"> See also: Lists of nebulae </Td> </Tr> <P> The Orion Nebula (also known as Messier 42, M42, or NGC 1976) is a diffuse nebula situated in the Milky Way, being south of Orion's Belt in the constellation of Orion . It is one of the brightest nebulae, and is visible to the naked eye in the night sky . M42 is located at a distance of 1,344 ± 20 light years and is the closest region of massive star formation to Earth . The M42 nebula is estimated to be 24 light years across . It has a mass of about 2,000 times that of the Sun . Older texts frequently refer to the Orion Nebula as the Great Nebula in Orion or the Great Orion Nebula . </P> <P> The Orion Nebula is one of the most scrutinized and photographed objects in the night sky, and is among the most intensely studied celestial features . The nebula has revealed much about the process of how stars and planetary systems are formed from collapsing clouds of gas and dust . Astronomers have directly observed protoplanetary disks, brown dwarfs, intense and turbulent motions of the gas, and the photo - ionizing effects of massive nearby stars in the nebula . </P>

Where is the nebula in the orion located