Omega Centauri is one of roughly 150 globular clusters in our Milky Way Galaxy. The behemoth stellar grouping is the biggest and brightest globular cluster in the Milky Way, and one of the few that can be seen by the unaided eye. By analyzing archived images taken over a four-year period by Hubble's Advanced Camera for Surveys, astronomers have made the most accurate measurements yet of the motions of more than 100,000 stars within the cluster - completing the largest and most detailed survey of the internal workings of a globular cluster to date.