Scientists record mysterious ‘hum’ coming from the Earth itself

Don’t panic, but our planet constantly makes a low humming noise – and scientists finally recorded it at the bottom of the sea.

Scientists have been trying to detect it since the 50s, and the first study confirming ‘the hum’ was published in 1998.

Previous studies have measured it on land, using seismometers, but new measurements at the bottom of the sea could mean that scientists can finally puzzle out what’s causing it.

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The hum is known as ‘free oscillations’, caused by slight expansion and contraction of the Earth – and one theory is that it’s caused by the pounding of ocean waves, according to ScienceAlert.

Researchers led by Martha Deen at the Paris Institute of Earth Physics used 11 months worth of data from 57 seismometer stations in the Indian Ocean.

They removed interference until they were left with a hum between 2.9 and 4.5 millihertz – far below the threshold of human hearing.

Deen and her co-authors believe the hum could be used to map the interior of our planet.

Scientists traditionally examine the interior using seismic waves generated from earthquakes, but this only works at specific times and in areas where quakes commonly occur.

Using the hum signal as a source of seismic waves would avoid this problem because the hum is generated continuously in many ocean-continent areas at the planet’s surface.