The hum is beneath the threshold of human hearing. Image Credit: CC BY-SA 3.0 NikoLang
Our planet is making a continuous low humming sound and nobody is quite sure what is causing it.
Efforts to directly detect the sound, known as 'the hum', have been ongoing since the 1950s, but now a team of researchers led by Martha Deen at the Paris Institute of Earth Physics have finally found a way to record the notorious sound using 57 seismometer stations situated in the Indian Ocean.
"A low noise level is needed to observe the small signal amplitude of the hum," the team wrote. "At the ocean bottom, the noise level at long periods is generally much higher than at land stations."
At between 2.9 and 4.5 millihertz, the hum is far below the threshold of human hearing.
The sound is caused by the slight expansion and contraction of the planet, however it remains unclear exactly why this happens. One theory suggests that the pounding of the waves may be to blame.
By directly analyzing the hum, scientists are now hoping to be able to fully explain the phenomenon and believe that it may even be possible to use it to help map the interior of the Earth.
Source: Yahoo! News | Comments (13)