Orion Nebula

Messier 42 (NGC 1976), the Great Orion Nebula, is the closest and most studied star-forming region in the sky, lying approximately 1,600 light-years away in the Sword of Orion — the short vertical line of stars hanging below Orion's three-star Belt. Astronomical records of the Orion Nebula reach back centuries, though credit for its first systematic telescopic description is usually given to Nicolas-Claude Fabri de Peiresc in 1610; it was later memorably described by William Herschel as "the chaotic material of future suns." Galileo, remarkably, pointed his telescope at the same region and catalogued the stars but missed the nebula entirely. Charles Messier added NGC 1976 to his list in 1769.

The Orion Nebula is not merely a glowing cloud but an active stellar nursery: it contains enough raw material to form roughly 10,000 stars the mass of the Sun. Embedded within the brightest central region are the four hot young stars of the Trapezium (Theta1 Orionis), a tight grouping that provides the ultraviolet energy to ionize the surrounding hydrogen gas and make the nebula glow. Long-exposure images reveal a turbulent landscape of glowing filaments, dark lanes, and dense globules called proplyds — protoplanetary disks silhouetted against the bright nebula — where individual solar systems may be forming today. The nebula's bright central region spans roughly six light-years and is merely the visible face of a vast molecular cloud that extends through much of Orion.

On any clear night M42 is visible to the naked eye, and binoculars reveal a glowing smear of light immediately — it is the easiest nebula in the sky. This image was taken as part of the Advanced Observing Program (AOP) at the Kitt Peak Visitor Center in 2014.