(much larger hi-res picture at link) Globular clusters are gravitationally-bound groupings of stars which orbit galaxies. These objects typically contain hundreds of thousands of stars that are thought to have formed at roughly the same time as their host galaxy. They are denser and more spherical than open star clusters like the famous Pleiades. The large mass in the rich stellar center of the cluster pulls the stars inward to form a ball of stars. The word globulus, from which these clusters take their name, is Latin for small sphere. It is thought that every galaxy has a population...