Supported observations indicate that researchers used Hubble and Gaia telescope data to examine stellar clusters within the Milky Way's inner 20,000 light-years, each containing hundreds of thousands of stars. These clusters are linked by some sources to a possible merger with a smaller galaxy roughly one-quarter the Milky Way's size that contained stars totaling 500 million solar masses when the universe was under 15 percent of its current age. Timing estimates of 11.8 or 12 billion years ago remain disputed between CNA and The Conversation sources.