Like a restorer examining an ancient manuscript under different lights, astronomers used DESI spectroscopy and the GS3 Hunter algorithm to peer beneath the surface of the Gaia Sausage. They found not a monolith, but a palimpsest: four substructures aged 7 to 12 billion years, differing in chemical c
arXiv:2606.04462v1 · 2026-06-03