Astronomers discover most powerful explosions since the Big Bang
06 Jun 2025

Astronomers from the University of Hawaii have discovered a new class of cosmic explosions, called "extreme nuclear transients" (ENTs). These are the most powerful events ever witnessed since the Big Bang.

The phenomenon occurs when massive stars, at least three times more massive than our Sun, are torn apart by supermassive black holes at the centers of distant galaxies.

The most powerful ENT studied, named Gaia18cdj, released an astonishing 25 times more energy than the most powerful supernovae known.

ENTs are different beasts
Discovery details

The explosions caused by these events release energy equivalent to that of 100 Suns over their entire lifetimes, making them visible across vast cosmic distances.

Jason Hinkle, the study's lead author, said, "We've observed stars getting ripped apart as tidal disruption events for over a decade, but these ENTs are different beasts."

He added that "not only are ENTs far brighter than normal tidal disruption events," but they also remain luminous for years.

How the ENTs were discovered
Research findings

Hinkle discovered these ENTs while searching public transient surveys for long-lived flares from galaxy centers.

He found two unusual flares in data from Gaia mission that brightened over a longer timescale than known transients and lacked features typical of known transients.

"Gaia doesn't tell you what a transient is, just that something changed in brightness," said Hinkle. "But when I saw these smooth, long-lived flares from the centers of distant galaxies, I knew we were looking at something unusual."

ENTs can help us study supermassive black holes
Cosmic exploration

The discovery of ENTs offers a new way to study supermassive black holes in distant galaxies. Their brightness allows astronomers to observe them across vast cosmic distances.

"ENTs provide a valuable new tool for studying massive black holes in distant galaxies," said Benjamin Shappee, co-author of the study.

He added that by observing these prolonged flares, we learn about black hole growth during an era when galaxies were forming stars and feeding their supermassive black holes.