Astronomers led by the University of Cambridge have observed a galaxy that suddenly stopped forming new stars more than 13 billion years ago. This galaxy appears to have lived fast and died young: star formation occurred quickly and stopped almost as quickly, which is unexpected at such an early stage in the evolution of the universe.
It is unclear whether this galaxy's 'off' state is temporary or permanent, and what caused it to stop form new stars. This observation is one of the most profound yet made with Webb.