Space Telescope Science
Billions of years ago in our Milky Way galaxy, long before the Earth was born, swarms of stars formed in giant clusters. Each grouping of stars, called a globular cluster, was held together by the mutual gravity of its stars. These globular star clusters became the homesteaders of our Milky Way.
Astronomers have probed the galaxy's globular clusters using many telescopes, including NASA's Hubble Space Telescope, to dig into the Milky Way's past and uncover what was happening in these early, formative years. Recent stellar archaeological excavations with Hubble into one such globular cluster, 47 Tucanae, have allowed astronomers to piece together a timeline of the stars' births.