Astronomers have identified three ultra-massive galaxies — nearly as massive as the Milky Way — already in place within the first billion years after the Big Bang. This surprising discovery was made possible by the James Webb Space Telescope’s FRESCO program, which uses the NIRCam/grism spectrograph to measure accurate distances and stellar masses of galaxies. The results indicate that the formation of stars in the early Universe was far more efficient than previously thought, challenging existing galaxy formation models. 

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