James Webb spots high‑redshift Einstein ring, challenging models

The James Webb Space Telescope imaged a high-redshift Einstein ring produced by a massive foreground galaxy lensing a background source. Analysis shows the ring's shape and inferred mass profile conflict with current galaxy formation models, implying a galaxy that is too massive and concentrated for its epoch. The mismatch challenges assumptions about how quickly galaxies assemble and how dark matter clumps in the early universe. If confirmed, the result will force revisions to cosmological simulations and motivate targeted follow-up observations.