Early quasars blast out kinetic energy at 260% of their total light output, effectively choking off the birth of new stars in their host galaxies.

JWST observations of the early universe reveal that these luminous objects produce galaxy-scale outflows at a rate nearly seven times higher than in later eras. These violent winds are powerful enough to strip gas from a galaxy before it can collapse into stars. Astronomers were puzzled by why some of the oldest galaxies in the universe stopped growing so suddenly. This data provides the first direct evidence of a cosmic 'off switch' that operates with extreme efficiency shortly after the Big Bang. This mechanism explains the existence of 'red and dead' galaxies that appear far earlier than standard models predicted. It shows that the early universe was far more violent than we ever imagined.