Imagine trying to understand how a football game works based on just a few fuzzy snapshots of the game in play. Astronomers have faced this challenge when it comes to understanding the dynamics of the beehive swarm of stars in the globular star clusters that orbit our Milky Way Galaxy. Now, NASA’s Hubble Space Telescope has provided astronomers with the best observational evidence to date that globular clusters sort out stars according to their mass, governed by a gravitational billiard ball game between stars.
https://hubblesite.org/contents/news-releases/2006/news-2006-33.html