Hubble and Gaia Data Pinpoint Earliest Milky Way Merger, Extending Galaxy's Known History

New data from the Hubble Space Telescope and Gaia has revealed definitive evidence of a dwarf galaxy merging with the young Milky Way approximately 11.8 billion years ago. This discovery extends the known history of our galaxy's evolution by 1.8 billion years, offering crucial insights into how the Milky Way formed its current spiral structure. It highlights the early contribution of external galaxies to our galaxy's growth.