Wen-Long Zhang

In October 2022, the space-based detector GECAM-C caught the most powerful gamma-ray burst ever seen, GRB 221009A — an explosion that briefly became the brightest source of gamma rays in the sky. But the most interesting part came after: the instrument detected a series of additional flares, and one of them was record-breaking.

The night sky is occasionally pierced by short radio waves, like flashes from distant lighthouses. Most are barely noticeable, but sometimes a signal arrives so strong it outshines all others. It was just such a burst, named FRB 20250316A, that the Canadian radio telescope CHIME caught. It was so bright that astronomers decided to check just how likely such an event really is.

An avalanche in a sandpile starts with a single grain. No one knows exactly where it will slip or how big the slide will be. But if you keep pouring sand, the pile itself reaches a state where avalanches of all sizes, from tiny trickles to massive collapses, follow the same law.