A photo of the Orion Nebula from the Hubble orbiting space telescope. This nebula is located in the Orion Constellation, hence the name Orion Nebula. The Orion Nebula (also known as Messier 42, M42, or NGC 1976) is a diffuse nebula situated 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 2000 times the mass of the Sun. Older texts frequently refer to the Orion Nebula as the Great Nebula in Orion or the Great Orion Nebula. 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. Nebula possibly discovered 1610 by Nicholas-Claude Fabri de Peiresc. Independently found by Johann Baptist Cysatus in 1611. Trapezium cluster found as multiple star by Galileo Galilei in 1617. The Orion Nebula Messier 42 (M42, NGC 1976) is the brightest starforming, and the brightest diffuse nebula in the sky, and also one of the brightest deepsky objects at all. Shining with the brightness of a star of 4th magnitude, it visible to the naked eye under moderately good conditions, and rewarding in telescopes of every size, from the smallest glasses to the greatest Earth-bound observatories as well as outer-space observatories like the Hubble Space Telescope. It is also a big object in the sky, extending to over 1 degree in diameter, thus covering more than four times the area of the Full Moon. As i