As we’ve explored on BLDGBLOG before, the earth is constantly humming. Specifically, there “is a low rumble continually present in the ground even when there are no earthquakes happening,” and it is “detectable only by very sensitive seismometers. Its frequency is near 10 millihertz, below the range of human hearing.”
Now, though, out of the mess of competing explanations – which have included everything from changes in global air pressure (or wind rocking against mountains), to constant, almost undetectably small earthquakes deep inside the earth’s crust – the hum’s cause has apparently been found.
And he is being held by Afghan authorities in a small – wait –
As it happens, the hum’s real sonic origins “appeared to be linked to large ocean storms along certain coastlines,” New Scientist writes, but the mechanism itself remained a mystery.
It now seems that the hum begins rather humbly, so to speak, with “the combination of two waves of the same frequency travelling in opposite directions.” These “alternately cancel out and amplify each other,” creating “a standing wave that ‘goes thump, thump, thump on the ocean floor’.”
This, then, is the secret of terrestrial resonation.
After all, if you take millions upon millions of these standing waves every day of the year, along every coastline, in ceaseless percussion, you get an earth that quietly hums – a spherical musical instrument that rotates through space.

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