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Seven-hour gamma-ray burst challenges scientific models
Astronomers have unveiled details of GRB 250702B, the longest gamma-ray burst on record, which persisted for nearly seven hours following its detection on July 2, 2025. Captured by NASA's Fermi Gamma-ray Space Telescope, the event featured multiple intense episodes spanning 25,000 seconds, surpassing the prior benchmark by almost twice the duration.
Jonathan Carney, a PhD student leading the study at the University of North Carolina at Chapel Hill, noted that the burst's extraordinary length defies current models explaining gamma-ray bursts. "This was the longest gamma-ray burst that humans have observed long enough that it does not fit into any of our existing models," Carney stated.
The phenomenon originated in a massive, dust-shrouded galaxy roughly 8 billion light-years distant. Scientists propose scenarios such as the collapse of a massive star, a black hole colliding with a helium star, or a star disrupted by a black hole's gravity.
Follow-up analysis with the James Webb Space Telescope exposed the host galaxy as a intricate, dust-laden environment that blocks visible light, complicating efforts to pinpoint the exact trigger. Igor Andreoni, an assistant professor at UNC-Chapel Hill, emphasized the uncertainty: "We're not sure what caused this record-breaking event."
This gamma-ray burst underscores gaps in our grasp of extreme cosmic occurrences, prompting refined theories on stellar deaths and high-energy emissions.
