Astronomers Observe Record-Breaking Gamma-Ray Burst Lasting Over Seven Hours

On July 2, 2025, NASA's Fermi Gamma-ray Space Telescope detected an unprecedented gamma-ray burst (GRB) designated GRB 250702B. Unlike typical GRBs, which last from milliseconds to minutes, this event persisted for over seven hours, making it the longest GRB ever observed.

The burst exhibited multiple peaks over several hours, with initial gamma-ray emissions lasting at least seven hours and additional flares detected in the following days.

Subsequent observations using the Very Large Telescope and the Hubble Space Telescope confirmed that GRB 250702B originated from a galaxy billions of light-years away, beyond the Milky Way.

The extraordinary duration and repeating nature of GRB 250702B challenge existing models of GRB origins. Traditional explanations involve the collapse of massive stars or the merger of neutron stars, both leading to the formation of black holes and resulting in short-lived GRBs.

Researchers are considering alternative scenarios, such as a black hole consuming a star over an extended period or a tidal disruption event involving an intermediate-mass black hole.

Further studies are underway to understand the mechanisms behind this exceptional event and its implications for astrophysics.