The Laser Interferometer Gravitational-wave Observatory (LIGO) is no stranger to making history and breaking records. In 2015, its twin detectors based in Livingston, Louisiana, and Hanford, Washington, made the first ever detection of gravitational waves.

A physics conference has received a report of the gravitational wave from the heaviest pair of black holes we’ve so far observed merging. The result is larger than theoretical models allow through straight-forward means,

The event is the most massive black hole merger ever recorded by gravitational wave detectors and has forced physicists to rethink their models of how the enormous objects form. The signal was recorded when it hit detectors on Earth sensitive enough to detect shudders in space-time thousands of times smaller than the width of a proton.