3 days ago
‘Biggest Booms Since The Big Bang' Found As Black Holes Shred Stars
Caption: Artist's concept of the formation of Extreme Nuclear Transients (ENTs).
Astronomers have captured the most energetic explosions ever recorded in the universe since the big bang as massive stars get ripped apart by supermassive black holes.
These Extreme Nuclear Transients, as they've been named, are a new class of rare and powerful cosmic explosions so bright they appear to release more energy than 100 supernovae (exploding stars).
Black holes are such strong gravity that nothing can escape from them, not even photons of light. Supermassive black holes are the most massive type and reside at the centers of galaxies. While some of these black holes continuously consume gas and dust and glow for millions of years, others lie dormant — only revealing themselves when an unlucky star drifts too close. ENTs may be a glimpse into these otherwise unseen objects.
'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,' said Jason Hinkle, a doctoral graduate of the University of Hawaii's Institute for Astronomy, who led the study published this week in Science Advances. These powerful events don't just flare and fade quickly. It can take over 100 days for an ENT to reach peak brightness and more than 150 days to dim to half its maximum.
A tidal disruption event is when a star gets 'spaghettified' by a supermassive black hole, causing a brilliant flare, but an ENT is even more powerful. 'Not only are ENTs far brighter than normal tidal disruption events, but they remain luminous for years, far surpassing the energy output of even the brightest known supernova explosions," said Hinkle. These flares occur in the centers of galaxies and radiate more energy than any previously known event.
At least 10 million times less frequent than supernovae, ENTs occur when massive stars — at least three times more massive than our sun — come too close to a supermassive black hole. A tidal disruption follows, tearing the stars apart and releasing more energy than 100 supernovae. What's different about them is their speed — ENTs allow astronomers to watch as a massive star is 'digested' over time by a supermassive black hole.
'These ENTs don't just mark the dramatic end of a massive star's life,' said Hinkle. 'They illuminate the processes responsible for growing the largest black holes in the universe.'
Artist's concept of the formation of Extreme Nuclear Transients (ENTs).
The research included data on the most energetic event yet recorded, an ENT named Gaia18cdj. A typical supernova emits about as much energy as the sun ever will over 10 billion years. Gaia18cdj emitted 25 times more energy than the most powerful supernova ever observed.
The discovery came from scientists analyzing data from the European Space Agency's Gaia mission, which made three trillion observations of two billion stars while orbiting the sun between 2014 and 2025 when it ran out of fuel. It recorded unexplained flares in 2016 and 2018, with scientists discovering another — called ZTF20abrbeie and nicknamed 'Barbie' — in 2020, using data from the Zwicky Transient Facility survey telescope in California.
Follow-ups were then made using data from other telescopes, including the Keck Observatory in Hawaii and NASA's Neil Gehrels Swift Observatory and WISE spacecraft.
Artist's concept of the formation of Extreme Nuclear Transients (ENTs).
Although all astronomy is looking back in time (even the sun's light is eight minutes old), the brightness of ENTs allows them to be seen over vast distances. That opens up the possibility of seeing them in a time called the 'cosmic noon,' when the universe was half its current age. This was "when galaxies were happening places — forming stars and feeding their supermassive black holes 10 times more vigorously than they do today,' said Benjamin Shappee, Associate Professor at IfA and co-author of the study. 'ENTs provide a valuable new tool for studying massive black holes in distant galaxies.'
NASA's Nancy Grace Roman Space Telescope, launching as early as 2026, will use its infrared vision to catch these rare flashes from over 12 billion years ago — when the universe was just 10% of its current age — and help astronomers trace how black holes shaped galaxies over cosmic time.
Wishing you clear skies and wide eyes.
