The seven hour explosion nobody could explain
Recorded: March 21, 2026, 10 p.m.
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The seven hour explosion nobody could explain Topics Week's top Latest news Unread news Subscribe Science X Account Sign In Sign in with Forget Password? Not a member? Learn more Nanotechnology Physics Earth Astronomy & Space Chemistry Biology Other Sciences Medicine Technology share this! Share Tweet Share Home Astronomy & Space Astronomy March 16, 2026 The seven hour explosion nobody could explain by Mark Thompson, Universe Today edited by Editors' notes This article has been reviewed according to Science X's fact-checked peer-reviewed publication trusted source proofread The GIST Add as preferred source Positions on the sky of all gamma-ray bursts detected during the BATSE mission. Credit: NASA Gamma-ray bursts are the most violent explosions in the universe. In a fraction of a second, they can release more energy than the sun will emit across its entire 10-billion-year lifetime. Most are over before you've had time to register them, gone in seconds, minutes at most. So when something arrived on 2 July 2025 that kept going for seven hours, fired three distinct bursts spread across an entire day, and then left behind an afterglow lasting months, astronomers knew immediately they were looking at something completely new. GRB 250702B, detected by NASA's Fermi Gamma-ray Space Telescope, is the longest gamma-ray burst ever recorded and it dwarfs all others in duration. Of the roughly 15,000 bursts cataloged since the phenomenon was first recognized in 1973, only a handful even approach its duration. Normal gamma-ray bursts don't repeat. They arise from cataclysmic, one-time events, maybe a pair of neutron stars colliding, or a massive star collapsing in on itself. GRB 250702B did neither. "This is certainly an outburst unlike any other we've seen in the past 50 years," said one member of the detection team. The hunt for an explanation has occupied astronomers ever since. The orange dot at the centre of this image is GRB250702B, a gamma-ray burster that repeated several times over the course of a day, an event unlike anything ever witnessed before. Credit : NASA The researchers propose that GRB 250702B was produced when an ordinary star like our sun wandered too close to one of these intermediate mass black holes and was torn apart by its tidal forces. As the shredded stellar material spiraled inward and was consumed, it powered a relativistic jet of particles firing outward at close to the speed of light, generating the extraordinary gamma-ray emission Fermi detected. Crucially, the repeating nature of the bursts fits this picture neatly. The star wasn't necessarily destroyed in one go. Models suggest it could have been partially stripped across multiple close passes before final disruption, each encounter generating a fresh burst of emission which would explain the near regular spacing of the three Fermi triggers. Artist's illustration of a bright gamma-ray burst occurring in a star forming region. Energy from the explosion is beamed into two narrow, oppositely directed jets. Credit: NASA/Swift/Mary Pat Hrybyk-Keith and John Jones The event's location adds another intriguing detail since GRB 250702B sits around 5.7 kiloparsecs from the center of its host galaxy, well away from the supermassive black hole at the galaxy's core. That's exactly where you might expect a wandering intermediate mass black hole to lurk. Publication details Journal information: Key concepts Provided by Citation: This document is subject to copyright. 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The discovery of GRB 250702B, a gamma-ray burst, presented a significant challenge to astronomers due to its unprecedented duration—seven hours—and unusual characteristics. As detailed by Mark Thompson in Universe Today, this burst, detected by NASA’s Fermi Gamma-ray Space Telescope, was unlike any previously observed, exhibiting three distinct bursts spread across a single day followed by a months-long afterglow. This extended event prompted a global effort to understand its origins. Initially, the scientists posited that the event represented a completely new phenomenon. However, Jonathan Granot and colleagues, in a paper published in the Monthly Notices of the Royal Astronomical Society, proposed an explanation centered around intermediate mass black holes (IMBHs). These black holes, theorized to exist between stellar mass and supermassive varieties, have remained elusive to detect. The research team hypothesized that a normal star, venturing too close to an IMBH, would be torn apart by tidal forces, generating a relativistic jet of particles—the source of the gamma-ray emission. The repeating nature of the bursts aligned with a scenario of incremental, multiple disruptions of the star encountering the IMBH, each triggering a new burst. The location of GRB 250702B—approximately 5.7 kiloparsecs from the center of its host galaxy—further supported the IMBH theory. This distance aligns with the expected location for a wandering IMBH, distinct from the supermassive black hole at the galaxy’s core. If this interpretation holds true, it would represent the first documented instance of a relativistic jet originating from an IMBH during a stellar disruption event, marking a crucial step forward in understanding these enigmatic objects. Despite the compelling evidence, the findings remain subject to ongoing investigation and debate within the scientific community. Several alternative models continue to be explored, and definitive confirmation requires further observation and analysis. The seven-hour burst, therefore, serves as a catalyst for continued astronomical research, driving the exploration of these extreme energetic phenomena and the fundamental processes governing their creation. |