Ladies and gentlemen, say hello to Messier 20 and Messier 21 (M20 and M21). The first object you noticed was probably M20, the colorful Trifid nebula. This nebula is a hot destination for amateur astronomers given the fact that it’s bright and easy to see through a small telescope. It’s located in the constellation Sagittarius, about 5,000 light-years from Earth.
The nebula itself is a star forming region, thus it offers us keen insight into the early stages of star formation, from the beginning ’embryonic’ stage to the actual birth. The newly-born stars help to energize the nebula and their solar winds shape it, turning the region into this piece of cosmic art. For some scale, the dust lanes that trisect the nebula are about 40-light-years long; and about 300,000 years old. Because of this, the Trifid nebula is one of the youngest star forming regions currently known to us.
M21 is the accompanying star cluster to the upper right. It’s affectionately called “M21” because, clearly all of the really good names were already taken. M21 is also estimated to be about 5,000 light-years away, though astronomers haven’t found a connection between the two objects. M21’s stars are about 7.5-million years older than those found in M20. They just so happen to share the same region of space.