Scientists solve decades-old mystery: Earth's hum is ocean waves

Since the 1960s, Earth has been known to emit a faint, ceaseless vibration — a planetary whisper too low for human ears, whose origin remained one of geoscience's quiet enigmas. Researchers have now traced this hum to the Southern Ocean, where rolling swells press against the planet's crust, stirring fluids within it and sending microseismic ripples across the entire globe. In solving this mystery, scientists remind us that the world beneath our feet is never truly still, and that the sea's restlessness is written into the very bones of the Earth.