The KNMI has recorded inaudible low-frequency sound (infrasound) from the impact of asteroid 2023 CX1, which broke apart over Normandy in France on February 13, 2023. The space rock was about one meter in size and was discovered only a few hours before impact. This is the first time a space rock has been so completely tracked: from discovery in space to finding pieces on Earth.
These measurements provide unique information about the power and progression of cosmic impacts
The infrasound from the explosion was detected at multiple stations in the Netherlands, including the KNMI measurement station in De Bilt, 450 kilometers away. The infrasound network of the nuclear test ban treaty also recorded the event. The farthest detection occurred in Russia, 5500 kilometers away. These measurements provide unique information about the power and progression of cosmic impacts.
More than a hundred pieces of the asteroid have been collected and examined in France. The study, to which an international group of nearly a hundred scientists contributed, was published on September 17, 2025, in the journal Nature Astronomy. Scientists from the KNMI and Delft University of Technology (TUDelft) contributed to the study.
