U.S. astronomers have detected intermittent flickering from a distant quasar
dating to the cosmic dawn, about 850 million years after the Big Bang — the
earliest such flicker observed. Brightness variations indicate the central
supermassive black hole is surrounded by a geometrically thin, optically thick
accretion disk: a flattened but very dense, radiation-trapping disk. Researchers
report the thin-disk configuration persists even when accretion rates approach
the theoretical maximum, a finding that informs models of early supermassive
black hole growth.
