Orion Nebula
A cloud of glowing gas 24 light years across, visible to the naked eye as a fuzzy star in Orion's sword.
The Orion Nebula, Messier 42, lies about 1,350 light years away and is roughly 24 light years across, nearly six times the distance from the Sun to Proxima Centauri. On a dark night it shows as a misty patch in the sword that hangs below Orion's belt, and binoculars reveal its glow.
It is the nearest large region of star birth to Earth. Clouds of hydrogen and dust collapse under their own gravity into new stars, and the most massive of them, the four bright stars of the Trapezium at its heart, flood the surrounding gas with ultraviolet light that makes it shine. In long-exposure photographs the red comes from hydrogen and the green from oxygen.
The Hubble and James Webb space telescopes have revealed hundreds of protoplanetary discs, nicknamed proplyds, around the young stars here: planetary systems in the making, some several times the size of our own solar system.
The nebula holds about 2,000 times the mass of the Sun, and its cluster of stars is young, mostly less than a few million years old, while the Sun is 4.6 billion. Even this vast nursery is a speck within the Milky Way, the next stop, which is about 4,000 times wider.
- Size
- 2.3 × 10¹⁷ m
- Distance
- about 1,350 light years
- Catalogue number
- M42
- Mass
- about 2,000 Suns