JWST weighs a distant 6-billion-solar-mass black hole in a 10-billion-light-year galaxy

Using the James Webb Space Telescope and gravitational lensing, astronomers tracked the motion of stars at the heart of the galaxy MRG-M0138 (about 10 billion light-years away) to weigh a dormant supermassive black hole of roughly 6 billion solar masses—the most distant black hole weighed by this method. The host galaxy is no longer forming stars, suggesting a past quasar phase that expelled gas and quenched star formation. The study, published in Science, helps chart how black holes and their galaxies grow and influence each other over cosmic time.