HomeScienceStrange 7-hour deep space explosion leaves scientists searching answers

Strange 7-hour deep space explosion leaves scientists searching answers

Astronomers tracked a gamma-ray burst lasting over 7 hours, unseen in visible light, from a dusty galaxy 8 billion light-years away, challenging existing models and raising new questions for science.

December 20, 2025 / 14:54 IST
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An artist’s illustration showing GRB 250702B, with a high-speed jet of material erupting from a heavily dust-filled galaxy. (Image: NOIRLab/NSF/AURA/M. Garlick)
An artist’s illustration showing GRB 250702B, with a high-speed jet of material erupting from a heavily dust-filled galaxy. (Image: NOIRLab/NSF/AURA/M. Garlick)

Astronomers are studying an unusually long gamma-ray burst detected on July 2. NASA’s Fermi Gamma-ray Space Telescope observed sustained emissions exceeding seven hours.

What happened during GRB 250702B observation
Gamma-ray bursts are usually detected once every day. This event, named GRB 250702B, behaved very differently. It became the longest-duration gamma-ray burst ever recorded. Scientists think it came from a rare explosion type. The explosion launched a narrow jet towards our solar system. That jet travelled at least 99% light speed.

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Astronomers worldwide moved quickly to trace its afterglow. They observed the event across all light wavelengths. Telescopes included Gemini in Chile and Hawaii. The Very Large Telescope in Chile participated. Hawaii’s Keck Observatory and Hubble also contributed.

In October, the infrared James Webb Space Telescope focused on GRB 250702B’s host galaxy, providing the sharpest view so far. (Image: NASA, ESA, CSA, H. Sears (Rutgers). Image processing: A. Pagan (STScI))