Space sent a mysterious signal – scientists have figured out what happened

Astronomers have detected a record-breaking seven-hour gamma-ray burst, GRB 250702B, registered by NASA's Fermi telescope on July 2, 2025. The signal lasted approximately 25,000 seconds, far exceeding typical durations. Scientists are considering the hypothesis of an interaction between a stellar-mass black hole and a helium star.

Astronomers have detected an unusual gamma-ray burst, GRB 250702B, which lasted about seven hours — a record duration for such events. The signal was registered by NASA's Fermi space telescope on July 2, 2025. The burst lasted approximately 25,000 seconds, significantly exceeding typical durations and making it one of the longest ever observed. Gamma-ray bursts usually occur when massive stars die or neutron stars merge, but in this case, scientists are considering a rarer scenario: the interaction of a stellar-mass black hole with a compact helium star. In this hypothesis, the black hole gradually consumes the star's matter, leading to a prolonged emission of high-energy radiation. Such events are difficult to detect and study, as they may be fainter than typical short bursts. Scientists hope that the launch of the COSI telescope in 2027 will expand the ability to search for new long-duration flares.