Scientists have discovered unexpectedly high levels of the rare radioactive isotope beryllium-10 in the Pacific seabed, suggesting a mysterious event occurred around 10 million years ago. This anomaly, identified through Accelerator Mass Spectrometry in ferromanganese crust samples, shows nearly double the expected levels of beryllium-10, which forms when cosmic rays interact with the atmosphere. The cause could be either earthly—such as a drastic change in ocean circulation—or extraterrestrial, potentially linked to a supernova or the Earth passing through a dense interstellar cloud that exposed it to a burst of radiation. If this anomaly is found globally, it could serve as a valuable "cosmogenic time marker" for dating geological and environmental records from millions of years ago. Further research is planned to investigate its origins and implications.