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: 3, Funny) by Anonymous Coward on Tuesday April 21 2015, @03:46PM
Because it doesn't know the words.
(Score: 1) by Paradise Pete on Tuesday April 21 2015, @05:19PM
Sheesh. The words are right there under the rocks. And of course eventually all things merge into one, and a river runs through it.
(Score: 0) by Anonymous Coward on Tuesday April 21 2015, @06:35PM
I wish it didn't hum in the evening and during the night when i'm trying to sleep! And it's not even a real song it's humming. So monotonical.