What did the James Webb Space Telescope reveal about the earliest galaxies?

The answer

The James Webb Space Telescope discovered galaxies dating back to just 300 million years after the Big Bang that are far more massive and structured than theoretical models predicted. In 2023, JWST identified JADES-GS-z14-0, a galaxy existing roughly 290 million years post-Big Bang, with a redshift of 14.32. These unexpectedly bright, well-organized early galaxies suggest that star formation began more rapidly than cosmologists assumed. Some contain billions of solar masses worth of stars, challenging the Lambda-CDM model of cosmology. These findings, published in Nature Astronomy, indicate that galaxy formation mechanisms in the early universe remain poorly understood.