Imagine an explosion in space so powerful it makes a typical exploding star (a supernova) look dim by comparison. Scientists have discovered a new class of cosmic blast, called Extreme Nuclear Transients (ENTs), sparked when supermassive black holes—the mysterious giants at the hearts of galaxies—shred massive stars, offering a dazzling new way to study these elusive objects and the early universe.
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This discovery reveals blasts far brighter and longer-lasting than previously known, providing a unique window into the universe’s most extreme events and the feeding habits of its largest black holes.
Meet the “Extreme Nuclear Transients”
For over a decade, astronomers have watched stars get too close to a black hole and be torn apart, an event known as a tidal disruption event (TDE). It’s often described as “spaghettification” because the star is stretched and pulled like pasta. These TDEs release a brilliant flare of energy.
But Extreme Nuclear Transients are different beasts. “We’ve observed stars getting ripped apart as tidal disruption events for over a decade, but these ENTs are different beasts, reaching brightnesses nearly ten times more than what we typically see,” explained Jason Hinkle, who led the study while at the University of Hawaii’s Institute for Astronomy.
These powerful cosmic blasts don’t just flash and disappear. They can take months to reach their peak brightness and remain incredibly luminous for years, releasing energy equivalent to over 100 supernovae combined.
A Cosmic Meal: What Happens During an ENT?
ENTs are incredibly rare, estimated to be at least 10 million times less frequent than supernovae. They occur when truly massive stars – stars at least three times heftier than our Sun – wander too close to a supermassive black hole. The black hole’s immense gravity tears the star apart, releasing an unprecedented amount of energy.
Unlike typical TDEs, ENTs seem to allow astronomers to observe the “digestion” process of a massive star by a supermassive black hole over an extended period. This doesn’t just offer a dramatic view of a star’s demise; it also helps scientists understand how the biggest black holes in the universe grow.
Artist's concept of a star being pulled apart by a massive black hole
How Scientists Found These Super-Bright Events
The research involved sifting through data from multiple telescopes. One event, named Gaia18cdj, turned out to be the most energetic explosion ever recorded by astronomers. To put its power in perspective, a typical supernova releases about as much energy as the Sun will over its entire 10-billion-year lifetime. Gaia18cdj emitted 25 times more energy than the most powerful supernova ever seen!
The initial clues came from analyzing data from the European Space Agency’s Gaia mission, which surveyed billions of stars. Gaia spotted unexplained flares in 2016 and 2018. Another ENT, nicknamed “Barbie” (ZTF20abrbeie), was later found in data from the Zwicky Transient Facility survey telescope in California.
Astronomers then used other powerful telescopes, like the Keck Observatory in Hawaii and NASA’s Neil Gehrels Swift Observatory and WISE spacecraft, to conduct follow-up observations and confirm the nature of these incredibly bright events.
Artist's concept of a star being pulled apart by a massive black hole
Why This Matters: Peering Back in Time
The extreme brightness of ENTs is a game-changer. It means we can potentially spot these events from incredibly vast distances across the universe. Looking across vast distances is like looking back in time because light takes so long to travel.
This opens up the exciting possibility of seeing ENTs that occurred during a period called “cosmic noon,” when the universe was only about half its current age. This was a time when galaxies were much more active, forming stars and feeding their supermassive black holes at a rate ten times higher than today. As study co-author Benjamin Shappee noted, “ENTs provide a valuable new tool for studying massive black holes in distant galaxies.”
Looking ahead, NASA’s upcoming Nancy Grace Roman Space Telescope, set to launch potentially in 2026, will use its infrared vision to search for these rare, bright flashes from even further back – when the universe was just 10% of its current age. By finding these ancient ENTs, astronomers hope to trace the fascinating connection between the growth of supermassive black holes and the evolution of galaxies throughout cosmic history.
The discovery of Extreme Nuclear Transients gives astronomers a powerful new way to explore the universe’s most extreme environments and understand how black holes shaped the cosmos over billions of years.
