Orion Nebula

Orion Nebula, bright diffuse nebula in the constellation Orion; also known as the Great Nebula of Orion and cataloged as M42 or NGC 1976. It is located near the middle of the "sword" hanging from Orion's "belt" of stars. Its central bright region is about 1° in diameter and it has a total extension of 3°. It is about 1,000 light-years distant and as many as 60 light-years in diameter. The nebula is an enormous cloud of gas surrounding a cluster of very hot young stars. To the naked eye the nebula appears to be a faint star but becomes a vague patch of light when viewed through binoculars. The bright region is divided into two sections, the northeast portion being cataloged separately as M43 or NGC 1982. The Orion Nebula is the nearest major site to earth of massive star formation.

---

Orion Nebula

Bright nebula, faintly visible to the unaided eye in the sword of the hunter's figure in the constellation Orion. About 1,500 light-years from Earth, it contains hundreds of very hot young stars clustered about a group of four massive stars known as the Trapezium. Radiation primarily from these four stars excites the nebula to glow. Discovered in the early 17th century, it was the first nebula to be photographed (1880).

---

Orion Nebula [ə′rī·ən ′neb·yə·lə]

(astronomy)

A luminous cloud surrounding Ori, the northern star in Orion's dagger; visible to the naked eye as a hazy object. Also known as Great Nebula of Orion.

---

Orion Nebula 

a very large gas-dust cloud, the closest nebula to our solar system.

Located about 300 parsecs from our solar system, the Orion nebula is visible in the constellation Orion on moonless winter nights as a pale, twinkling spot. It measures about 5.5 parsecs in diameter. At its center is a small cluster of stars, among which is the Trapezium, which comprises four physically linked, hot, bright stars. Ultraviolet light from these stars causes the gas in the nebula—consisting primarily of hydrogen—to glow. The dust in the Orion Nebula absorbs light, which is partially responsible for the nebula’s wispy appearance.