(CBS NEWS) — Far from the blaring cacophony of cities, towns and suburbs, there are far quieter soundtracks to be found -- the murmurs of wind rustling grasses, rushing waves tumbling onto beaches, the creaking of tree branches and trunks.
But underneath all that is yet another soundscape, a permanent, low-frequency drone produced by Earth itself, from the vibrations of ongoing, subtle seismic movements that are not earthquakes and are too small to be detected without special equipment.
Earth is "humming." You can't hear it, but it's ongoing. And now scientists have measured that persistent hum from the ocean floor, for the first time.
Advertisement - story continues below