Orion Nebula

The Great Orion Nebula, also known as M42, is a bright emission and reflection nebula described as "an unformed fiery mist, the chaotic material of future suns." It is the main part of a much larger cloud of which extends over a distance of several hundreds of light years. Besides the Orion nebula the giant cloud includes the following objects, often famous on their own: Barnard's Loop, the Horsehead Nebula region (also containing NGC 2024), and the reflection nebulae around M78. Already impressive in deep visible light photographs, the Orion Cloud is particularly gorgeous in infrared light.

The Orion Nebula itself is still a big object in the sky, with a linear diameter of about 30 light years. The nebula, on its northern end, is divided by a conspicuous dark lane. In the very neighborhood, to the north, there are also fainter reflection nebulae, partially reflecting the light of the Great Nebula. They are labeled with the NGC numbers 1973-5-7.

M42 itself is apparently a very turbulent cloud of gas and dust, full of interesting details. The major features got names on their own by various observers: The dark nebula forming the lane separating M43 from the main nebula extends well into the latter, forming a feature generally nicknamed the "Fish's Mouth". The bright regions to both sides are called the "wings", while at the end of the Fish's Mouth there's a cluster of newly formed stars, called the "Trapezium cluster". The wing extension to the south on the east is called "The Sword", the bright nebulosity below the Trapezium "The Thrust" and the fainter western (right) extension "The Sail".

Research on the Orion Nebula have revealed that the visible nebula, M42, the blister of hot, photo-ionized, luminous gas around hot Trapezium stars, is only a thin layer lying on the surface of a much larger cloud of denser matter, the Orion Molecular Cloud 1 (OMC 1).

Another major discovery was that of protoplanetary disks, the so-called "Proplyds" (planetary systems in formation) in M42. Investigations have revealed interesting interactions of the young hot Trapezium cluster stars with the protoplanetary disks: Their violent radiation tends to destruct the discs, so that the lower-mass stars forming here may loose the material needed to form planetary systems.

There is some evidence the Flaming Runaway Star AE Aurigae originated from this region.