09/24/2025
A powerful cosmic explosion just repeated three times in one day.
Gamma-ray bursts – or GRBs – are the most powerful explosions known to science. They’re usually triggered by the catastrophic collapse of a star or the shredding of one by a black hole, and they tend to happen just once.
But in July 2025, scientists watched one of these explosions repeat three times over just 24 hours.
That simply isn’t supposed to happen. GRBs are one-off events by nature. But this time, something exploded in space… and then did it again. And again.
NASA’s Fermi Gamma-ray Space Telescope first picked up the activity: four energetic bursts from a single patch of sky. Follow-up analysis confirmed that three were coming from the same source. Compared to typical GRBs that last seconds or less, these repeated bursts spanned hours – making them 100 to 1,000 times longer than normal.
The source lies far outside our galaxy. Its position was narrowed down thanks to a coordinated global effort involving the Einstein Probe (a Chinese–European mission), NASA’s Swift Observatory, the European Southern Observatory’s Very Large Telescope, and Hubble. Together, these observations confirmed it came from a distant galaxy several billion light-years away.
As for what caused it? Astronomers are still debating.
One theoryis a massive star undergoing a highly unusual supernova, where the collapse happens slowly, releasing energy over an extended period. If true, this would be a type of stellar death no one has ever documented.
Another possibility is that a a white dwarf star – a dense stellar remnant – being shredded by a rare, mid-sized black hole. Most black holes we detect are either small (like those formed from collapsed stars) or supermassive (at the centers of galaxies). But intermediate-mass black holes are elusive. Catching one in the act of destroying a star could help confirm they actually exist.
Whatever it was, it’s unlike anything we’ve seen since scientists began studying GRBs five decades ago.
📸Credit: ESO/A. Levan, A. Martin-Carrillo et al.
