Early galaxies may hide 4× more mass

JWST spectra of nine massive quiet galaxies show they hold far more low-mass stars than a Milky Way-like mix would predict. The oldest galaxy in the sample formed when the universe was still young, and it has the most bottom-heavy star mix of the set.1

If JWST’s “impossibly early” galaxies shared that same mix, their true stellar masses could rise by a factor of about 4 ± 1. That would sharpen the tension with galaxy-formation models that already struggle to grow such heavy systems so soon after the Big Bang.12