This immense ocean of swirling, chaotic gas is the Great Nebula in Orion. The nebula, known to astronomers as M42 or NGC 1976, is a huge stellar nursery where thousands of young stars are forming. In this image, portions of the clouds of gas are seen as ionized hydrogen and helium gas. Close scrutiny of the nebula reveals violent phenomena, the effects of young stars on the gas clouds.
M42 shines because of ultraviolet radiation emitted by the Trapezium, a cluster of a few hundred stars that draws its name from its four brightest members. The brightest and youngest stars in the cluster, known as O and B stars, emit invisible ultraviolet radiation
