Sometimes waves sloshing in opposite directions intersect sending vibrations deep down into Earth s crust

It’s a low, ceaseless droning of unclear origin that rolls imperceptibly beneath our feet, impossible to hear with human ears. A researcher once described it to HuffPost as the sound of static on an old TV, slowed down 10,000 times.

It’s comforting to think of Earth as solid and immovable, but that’s false. The world is vibrating, stretching and compressing. We’re shaking right along with it.

Source: Scientists are slowly unlocking the secrets of the Earth’s mysterious hum