Astronomers have observed a gamma-ray burst, GRB 250702B, unlike any seen before, which erupted multiple times over the course of a full day.

Gamma-ray bursts (GRBs) are typically catastrophic events caused by massive stars collapsing or stars being shredded by black holes, and they usually last only milliseconds to minutes.

GRB 250702B defied this pattern, with repeated bursts detected by NASA’s Fermi Gamma-ray Space Telescope and the Einstein Probe, making it a long-period repeating GRB—a phenomenon never before recorded.

Follow-up observations using the Very Large Telescope and the Hubble Space Telescope confirmed that the burst originated from a galaxy billions of light-years away, indicating an extraordinarily powerful extragalactic event, Space.com has reported.

Researchers are still investigating the source and cause of GRB 250702B, exploring possibilities such as unusual stellar collapse or an exotic tidal disruption event, while continuing to monitor the site with advanced telescopes to understand this mysterious cosmic explosion.