Astronomers have measured the most distant dormant black hole ever discovered using the James Webb Space Telescope.
For the first time, astronomers have used the James Webb Space Telescope (JWST) to “weigh” a dormant supermassive black hole over 10 billion light-years away, and yes this shatters the stellar dynamics distance record by about 15-fold. Hidden quietly at the core of galaxy MRG-M0138, the cosmic giant clocks in at roughly six billion solar masses, giving a very rare look into the universe during a time when it was only a quarter of its current age.
Silenced by Its Own Past
Published in Science (June 4, 2026), the study is led by Andrew Newman of Carnegie Science with senior author UCL's Richard Ellis. Observing MRG-M0138 at cosmological redshift 1.95—when the universe was roughly three billion years old—Newman's team found both the black hole and its host galaxy fully dormant: no new stars forming and no material accreting. They attribute this twin quiescence to an earlier quasar phase in which the black hole's explosive growth expelled the gas needed for star formation, rapidly starving the galaxy while silencing its central engine.
Gravity as a Telescope
A sleeping black hole does not radiate any energy and can be identified solely through its gravitational attraction of nearby stars. Scientists employed stellar dynamics analysis involving the velocities of stars in the vicinity of the core of MRG-M0138. This would have been extremely difficult from such an enormous distance, but a galaxy cluster between us and the galaxy acted as a gravitational lens, magnifying the image by a factor of 30. Finally, the stellar kinematics were observed using the NIRSpec Integral Field Spectrograph of JWST, reaching a distance unprecedentedly 15 times farther than before.
