Messier 56

Messier 56 (M56) lives about 32,900 light years away in the small Lyra constellation. Charles Messier discovered it in 1779, and like the other globular clusters he discovered, he labeled it a “nebula without stars.” Given the optics of the day, that’s understandable. Five years later, William Herschel was able to resolve it into stars.

M56 has a very low content of elements heavier than hydrogen or helium. This leads scientists to believe that it may have been captured from a small satellite galaxy rather than having formed with the Milky Way.

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.

M56

Distance: 32,900 light years

Number of stars: 230,000

Diameter: 84 light years

Age: 13.7 billion years