This is Messier 42, the Great Nebula in Orion. It's a complex region of space around 1350 light years away, and is a place of vigorous star formation. The nebula itself is 24 light years across and weighs in at about 20 solar masses. The nearest star to us other than the sun is 4.2 light years away - this nebula is 6 times that in extent! It is one of the few deep sky objects that can clearly be seen with the naked eye - the ancients saw it as the middle star in Orion's sword. My eyes cannot see the nebulousness without help; it looks to me like a slightly fuzzy star, but even with binoculars it shows up as something special.

To the south of M42 is another structure complicated enough to have 4 separate catalogue numbers. It is a reflection nebula, picking up the light from nearby stars.

Much of this complexity comes from location - all these objects are in the middle of a vast molecular cloud, the size of the whole constellation of Orion as we see it. All that matter gravitating away is bound to produce something spectacular!