Now, in 2017, scientists have discovered that the earth is constantly humming. Using Ocean-Bottom Seismometers (OCBs), they recorded the natural frequency of the Earth and uncovered its natural resonance.
To record the sound of the Earth, scientists deployed 57 of these spheres between September 2012 and November 2013. These spheres then made numerous recordings between 2.9 and 4.5 millihertz to finally capture the sound of the planet. For reference, that’s a recording more than 10,000 lower than what the human ear can detect.
Scientists have known the Earth had its own sound since around 1959, but it’s been undetectable until now. Nobody really knows what causes the vibration.
The hum also seems to be global. Despite measurements being made in the sea, the research team stripped back all other sounds from the ocean to be left with the Earth’s hum. They then compared it to the land-based sound research being done in Algeria and discovered the two match up.
The findings were published online Nov. 27 (2017) in the journal Geophysical Research Letters.