The 26-second pulse of the Earth: for over 60 years, seismic enigma still intrigues science

Every 26 seconds, without fail, the planet emits a dull pulsation, a vibration that crosses continents and oceans with disconcerting regularity. It is not a meteorological phenomenon or just background noise: it is a microseism, a low-intensity earth tremor of mysterious origin. The history of this phenomenon dates back to the 1960s when geologist Jack Oliver from the Lamont-Doherty Geological Observatory at Columbia University detected a peculiar seismic signal while reviewing records at various stations. He realized it was something different: a stable frequency and such marked periodicity that it stood out even on unsophisticated instruments. In 1962, Oliver published his discovery, defining the phenomenon as ‘a worldwide microseism storm with periods of about 26 seconds,’ according to Nature magazine.