Discovered by Charles Messier in 1781

Located approximately 28,000 light years from the Earth in the constellation Scorpius, M80 contains several 100,000s of stars and is one of the densest globulars in our galaxy.  The cluster contains a large number of so-called "Blue Stragglers" in its core, about twice as much as any other globular investigated with the Hubble Space Telescope.  These stars are massive bright blue stars, which appear near the main-sequence of the Hertzsprung-Russell diagram, and thus appear younger than the globular cluster's age.  The reason for the high percentage of these stars is very probably that these stars lost their cooler envelopes in close encounters with other stars.  The large number of these stars indicates an exceptionally high stellar collision rate in the core of this globular cluster.

¹http://www.seds.org/messier/m/m080.html