This glistening globular cluster, which is a gathering of hundreds of thousands of stars that are bound together by gravity, was first discovered in 1826 and described as a “pretty large, pretty bright” object. How would you describe it? Globular clusters are found around all large galaxies, but their origin and role in galaxy formation remain tantalizingly unclear. Astronomers recently discovered a black hole lurking at the heart of this globular cluster — its position was revealed by the strange movements of a star being quickly flung around a massive, invisible counterpart. This sparkling group of stars, seen by the Hubble Space Telescope (NASAHubble), also has some strange properties that make it unique amongst the more than 150 globular clusters belonging to the Milky Way. It has an extremely fast velocity with respect to the Sun, and its orbit is retrograde, meaning that it moves speedily in the opposite direction to the galactic center. The unusual behavior of this cluster su...