The Orion Nebula

The Orion Nebula
The middle “star” in Orion’s sword is actually the Orion Nebula, part of a huge system of interstellar gas and dust in which new stars are now
forming. The Orion Nebula is a region visible to the naked eye. It is 1600 ly (490 pc) from Earth and has a diameter of roughly 16 ly (5 pc).
This nebula’s mass is about 300 solar masses. (Left inset) This view at visible wavelengths shows the inner regions of the Orion Nebula. At the
lower left are four massive stars, the brightest members of the Trapezium star cluster, which cause the nebula to glow. (Right inset)
This view shows that infrared radiation penetrates interstellar dust that absorbs visible photons. Numerous infrared objects, many of which are
stars in the early stages of formation, can be seen, along with shock waves caused by matter flowing out of protostars faster than the speed
of sound waves in the nebula. Shock waves from the Trapezium stars may have helped trigger the formation of the protostars in this view