Hilo, Hawaii — Astronomers have made a groundbreaking discovery in the realm of cosmic explosions, unveiling a phenomenon far more powerful than anything previously observed. Dubbed “extreme nuclear transients” (ENTs), these astronomical events are reshaping our understanding of stellar destruction and black hole interactions. Recent research indicates that ENTs are the most formidable explosions recorded since the universe began.
The origin of ENTs stems from the violent demise of stars that are at least three times the mass of the Sun. When such a star is consumed by a supermassive black hole, the result is an explosion of unprecedented brightness and energy. Jason Hinkle, lead researcher from the University of Hawai’i’s Institute for Astronomy, emphasized the unique characteristics of these phenomena, stating that ENTs can be nearly ten times as bright as regular tidal disruption events and can remain luminous for years—far outpacing even the most brilliant supernovae.
This groundbreaking research builds on more than a decade of observations of tidal disruption events, during which astronomers have typically monitored stars being torn apart by black holes. However, the ENTs discovered signal a different process involving prolonged and explosive energy releases that last significantly longer than the brief flares generally associated with cosmic explosions.
Hinkle and his team made their initial discoveries while analyzing data from the European Space Agency’s Gaia mission, which has mapped over two billion stars. Among the data, they identified unusual light flares, including phenomena from 2016 and 2018, that defied the norm by persisting for multiple years. While most cosmic explosions typically last several weeks, these anomalies raised crucial questions about their nature.
A similar detection was reported in 2023 by another group of astronomers utilizing the Zwicky Transient Facility in California. Collaborating on these findings, Hinkle extended his observations using advanced telescopes, including the renowned Keck Observatory in Hawaii, to connect the dots between these extraordinary events.
Notably, one of the most spectacular ENTs, designated Gaia18cdj, emitted an astonishing amount of energy—25 times that of the most powerful supernova ever recorded. In just one year, it released an energy equivalent to what our Sun will produce throughout its entire existence, multiplied by a hundred. This immense energy output highlights the dramatic contrast between ENTs and traditional supernovae, which typically radiate energy comparable to just one Sun.
The intricate process of an ENT offers insights into the nature of black holes. Unlike traditional tidal disruption events that deliver a brief burst of energy as a star is rapidly consumed, ENTs involve a more protracted and violent dismantling of the stellar material. As the star is gradually torn apart, its remnants form a glowing disk that can persist for years, revealing essential information about the growth and evolution of supermassive black holes.
Co-author Benjamin Shappee, an associate professor at the Institute for Astronomy, emphasized the potential implications of these findings for understanding the early universe. He explained that by observing the long-lived emissions from these ENTs, scientists gain valuable perspectives on black hole development during a time when galaxies were forming stars at unprecedented rates.
The significance of these extreme nuclear transients extends beyond the final moments of massive stars, shedding light on the growth processes of the universe’s largest black holes. With ongoing research, astronomers hope to unlock the mysteries of these cosmic phenomena, which have ramifications for our understanding of the universe’s history and evolution.