Details: This poster shows the Orion Nebula, as photographed by NASA. The striking picture combines images taken through three separate filters, each designed to record different emission lines -- light from sulfur, oxygen, and hydrogen atoms glowing in the tenuous nebular gas. In this image, sulfur is red, hydrogen is green, and oxygen is blue.
The Orion Nebula (also known as Messier 42, M42, or NGC 1976) is a diffuse nebula situated south of Orion's Belt. It is one of the brightest nebulae, and is visible to the naked eye in the night sky. 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.