Orion nebula. Coloured infrared image of the Orion nebula, also known as Messier 42. The nebula is a HII region, a vast cloud of hydrogen ionised by bright, young stars in the Trapezium cluster. Just above the nebula is the OMC-2 molecular cloud and a cluster of red protostellar objects. At the top of the frame are two bright stars associated with another HII region, NGC 1977. All of these objects belong to the Orion Molecular Cloud, a star formation region 1470 light years from Earth. This image was made as part of the Two-Micron All-Sky Survey (2MASS) project.