This surprising discovery rewrites the Milky Way’s origin story

New simulations of Milky Way-like galaxies reveal that the strange split between two chemically distinct groups of stars may arise from several very different evolutionary events. Bursts of star formation, shifts in flowing gas, and even streams of metal-poor material from a galaxy’s outskirts can all create this double pattern. The findings challenge the long-held assumption that a major ancient collision caused the split.