The Orion Nebula
The Orion Nebula, aka Messier 42, situated to the south of Orion’s Belt in the constellation of Orion, is one of the brightest diffuse examples ever captured by astronomers. Colossal in scale and packed with thousands of stars of all ages, the nebula is atypical, vividly demonstrating the many processes involved in star creation.
The Orion Nebula consists of a dense mix of clouds of neutral gas and dust, star clusters, ionised volumes of gas and reflection nebulas (clouds of interstellar dust that reflect light from nearby stars). Structurally, the nebula forms a slightly off-spherical cloud of these various celestial features, with a sharp density gradient emanating from its core to its rim.
Temperatures inside the nebula range from 10,000 Kelvin (9,727 degrees Celsius/17,540 degrees Fahrenheit) in its central regions, to a fraction of that in its periphery. In addition, a wide range of velocities are apparent within its structure, with relative movements falling at 35,405 kilometres (22,000 miles) per hour, and local movements reaching up to 177,000 kilometres (110,000 miles) per hour.
The nebula’s composition makes it an ideal region for a stellar nursery, as proven by the imaging of over 3,000 stars of all ages by the Hubble Space Telescope. Indeed, only recently did NASA image a series of 150 protoplanetary discs within Messier 42 – each of which is a potential starting point for a solar system.