Messier 22 – The Great Sagittarius Cluster

One of the first globular cluster’s ever discovered, German astronomer Abraham Ilhe came across it one night in 1665 while looking for Saturn.

I shot this in a wide field because I wanted to show it in context. It’s set against the backdrop of the galactic plane near the galactic core. So the area is dripping with stars as well as emission material.

Messier 22 (M22) is unusual among globular clusters for the variety of objects in its midst. It contains four to six planet-sized objects not orbiting stars, it harbors two stellar-mass black holes, and it is one of only four globular clusters known to host a planetary nebula.

Globular clusters are ancient. They are many billions of years old—usually 10 to 13 billion years old—almost as old as the universe itself. The stars they contain tend to be very old as well, because star formation inside the cluster has largely ceased. The formation of globular clusters is not well understood. Current research leans toward the idea that they formed from very dense molecular clouds in the early universe. Some larger globular clusters may once have been dwarf galaxies whose larger star populations were stripped away from the core by larger galaxies.

M22 Facts

Distance: 10,000 light years

Number of stars: 70,000

Diameter: 99 light years

Age: 12 billion years