The Orion Nebula, so named because of its proximity to the belt of the Orion constellation, is one of the brightest nebulae in the night sky and a region where young stars are in the process of forming. Astronomers have studied the nebula and learned much about the formation of protoplanets and brown dwarf stars. The nebula and its surroundings are home to more than 2,000 stars.
Inside the nebula, clouds of hydrogen and other gases collapse under their own gravity, forming dense disks that spawn stars. The leftover material coalesces into planets, with heavier elements forming terrestrial planets and frozen gases coalescing into gas giants. Several systems in the process of forming are visible inside the nebula, giving astronomers a glimpse into what the solar system may have looked like in its earliest stages.
The earliest known observation of the nebula occurred in 1610, when a French astronomer noted its nebulous nature while observing Orion through a telescope. The fact that earlier astronomers with similar equipment were unable to locate it suggests that the sudden birth of one or more stars may have increased the nebula's visibility in the night sky. As of 2014, the most detailed examinations of the nebula were taken by the Hubble Space Telescope, identifying many of the young structures forming within the gas cloud.