Discovery of quasar variability and early accretion disk signatures at cosmic dawn

Nature Astronomy, Published online: 08 June 2026; doi:10.1038/s41550-026-02897-4 Decade-long multiwavelength observations reveal a quasar flickering in infrared and X-rays just 850 million years after the Big Bang. The variability provides direct observational constraints on the structure of accretion disks in early quasars.