Distant Black Hole Fades in a Human-Scale Timespan

Astronomers tracked galaxy J0218−0036 (about 10 billion light-years away) and found its central supermassive black hole dimmed by about 20x overall and ~50x in the active nucleus from the early 2000s to 2023. Dust obscuration was ruled out, pointing to an intrinsic drop in accretion with the Eddington ratio falling from ~0.4 to ~0.008. The observed e-folding timescale is roughly 2,000 days in the observed frame (~700 days rest frame), far faster than standard models predict, suggesting a change in accretion mode and challenging current black hole growth theories.