Could one cosmic event outshine 10 trillion suns? Astronomers have now observed just that a record-breaking flare from a supermassive black hole, fueled by the cataclysmic destruction of a massive star. The object, called a tidal disruption event (TDE), provides an unparalleled opportunity to study both the dynamics of extreme gravity and the early history of the universe.
The flare emanated from a black hole about 500 million times the mass of the Sun, within the active galactic nucleus J2245+3743, located approximately 10–11 billion light-years away. At such distances, the light we perceive today began its journey when the universe was less than a quarter of its current age. This supermassive black hole resides well above the typical threshold for producing visible TDEs, but its spin and the geometry of the star’s orbit may have aligned to tear the star apart outside of the event horizon. In relativistic astrophysics, this threshold is determined by the Hills mass, which depends on the black hole’s spin and on the inclination of the star’s orbit. For maximally rotating black holes, the Hills mass can be as much as 48% greater than for non-rotating ones, allowing disruption of more massive stars without their being swallowed whole.
The star, estimated at 30–200 solar masses, was “spaghettified”, stretched into a thin stream of plasma by the black hole’s tidal forces. “That material then spiralled around the supermassive black hole as it fell in,” said KE Saavik Ford, co-author of the study. As the debris orbited within the accretion disk, friction and compression heated it to millions of degrees, releasing electromagnetic radiation across the spectrum. At its peak, the flare was 30 times more luminous than any previously recorded TDE, radiating energy equivalent to converting the Sun’s entire mass into light via Einstein’s E=mc².
Such a distant and powerful event took long-term, multiwavelength monitoring to detect. The flare had been initially discovered in 2018 by the Zwicky Transient Facility, which noticed it brightening over three months. Follow-up observations with the W. M. Keck Observatory and NASA’s Wide-field Infrared Survey Explorer confirmed the emission was isotropic energy radiating in all directions, not just toward Earth, and ruled out supernova origins. Cosmological time dilation partially accounts for the persistence of the flare over seven years, when the estimated total duration should be about 11 years. Seven years here is two years there. We are watching the event play back at quarter speed.
From a physics perspective, TDEs are rare events-occurring once every 10,000 to 100,000 years per galaxy-but invaluable to probe black hole environments. Indeed, for most active galactic nuclei, the constant feeding of gas and dust can mask TDE signatures. The exceptional brightness of the flare of J2245+3743 pierced this veil, and for the first time, researchers could study how tidal debris interacts with pre-existing accretion flows. Indeed, similar nearby events, such as AT2019qiz, showed that outflows of material with velocities up to 10,000 km/s can obscure the early stages of disruption. The sheer energy output in this event overwhelmed such effects and made the flare visible across billions of light-years.
The consequences of these findings go far beyond this single flare event. Observations of high-energy flares in the early universe help trace the growth histories of supermassive black holes from their seed stages in dusty starburst galaxies to luminous quasars. Discoveries such as GNz7q, an object only 750 million years after the Big Bang, suggest that the remarkably rapid growth of massive black holes in dense and dust-rich environments is indeed feasible. Extreme TDEs at high redshift allow astronomers to explore refinements in models of black hole spin evolution, accretion physics, and galaxy-black hole coevolution.
Future facilities, like the Vera C. Rubin Observatory and the James Webb Space Telescope, will further extend the search for such ultra-bright TDEs; their debris streams and surrounding gas can then be studied in great detail spectroscopically. As Graham said, “We never would have found this rare event in the first place if it weren’t for ZTF when we see anything flare or change, we can see what it has done in the past and how it will evolve.”
