The
Orion Nebula is a
diffuse nebula situated south
of
Orion's Belt in the
constellation of Orion. It is one of the brightest
nebulae, and is visible to the
naked eye in the night sky. M42 is located at a distance of 1,344 ± 20
light years and is the closest region of massive
star formation to
Earth. The M42 nebula is estimated to be 24 light years across. It has a mass of about 2000 times the mass of the Sun. Older texts frequently referred to the Orion Nebula as the
Great Nebula in Orion or the
Great Orion Nebula.