One longstanding mystery in astronomy is how supermassive black holes got so heavy so early. JWST has shown evidence that supermassive black holes were already active and feeding 13 billion years ago. These are quasars, and they're so bright they drown out the light from the rest of the galaxy, but Webb can see it. Astronomers found that early black holes were much more massive than their host galaxies than modern versions.
MIT astronomers observe elusive stellar light surrounding ancient quasars
MIT astronomers observed the elusive starlight surrounding some of the earliest quasars in the universe. The findings may shed light on how the earliest supermassive black holes became so massive despite having a relatively short amount of cosmic time in which to grow.