Last October, astronomers witnessed a fleeting, extraordinarily bright gamma ray burst in the distant universe. Since dubbed the BOAT—the Brightest of All Time—a team of scientists has now reported an unusual structure to the gamma ray burst’s jet.

An exceptionally bright and long-lasting pulse of radiation from a space explosion swept over the planet on October 9, 2022. It was a gamma-ray burst (GRB). They are the most powerful types of explosions in the universe.

When scientists detected the gamma-ray burst known as GRB 221009A on October 9, 2022, they dubbed it the BOAT, or the brightest-of-all-time. Now, months after its initial burst, scientists studying GRB 221009A describe an unusual structure to the jet of material expelled during the explosion that may explain GRB 221009A’s extreme nature and why its afterglow remained visible for so long after the event.