According to Wired.co.uk, the source of the Earth's 'humming' noise may have been found:
A strange bell-like ring emitted by the Earth has left oceanographers confused for decades, but a new study may have found an explanation.
The low-frequency sound, which is inaudible to human ears but can be detected by seismic instruments, has frustrated scientists since the 90s. Theories suggested everything from electromagnetic radiation to earthquakes and secret military operations might be to blame. Although the sound is almost certainly too faint for humans to hear, some people claim to be plagued by a "tinnitus"-like noise -- including many residents of Bristol in the 70s, who said the sound caused headaches and even nosebleeds.
Link to research paper.[abstract only]
(Score: 2) by Jaruzel on Wednesday April 22 2015, @08:22AM
Deliberately didn't mention the Ocean Waves in the summary, coz, y'know it's a summary, and as good Soylentils we all should be following the links to the source and reading TFA.
I bet you are the sort of guy that delights in telling people the endings of films they haven't seen as well.... :)
This is my opinion, there are many others, but this one is mine.