Messier 107 (M107) – Crucifix Cluster

Although discovered much earlier, Admiral William Henry Smyth of the Royal Navy—an avid amateur astronomer in his retirement—observed Messier 107 (M107) in 1837 and remarked that five bright stars he could see in the cluster were arranged in the pattern of a Crucifix—hence it’s colloquial name, the Crucifix Cluster.

Although Charles Messier’s partner Pierre Méchain discovered it in 1782, and William Herscel independently discovered it a year later, it wasn’t added to the Messier Catalogue until 1947 by Helen Sawyer Hogg.

With an age of 13.95 billion years, M107 is one of the oldest globular clusters known.

Globular clusters are ancient collections of stars that are gravitationally bound together in a spheroidal shape. Some are almost as old as the universe itself. They can contain anywhere from tens of thousands of stars to millions of stars. The stars they house 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.

M107 Facts

Distance: 20,000 light years

Number of stars: 100,000

Diameter: 79 light years

Age: 13.95 billion years