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: 0) by Anonymous Coward on Tuesday April 21 2015, @08:18PM
Feel free to post a link to the free version of the article.
By the way, I do have access to the article and I'm pretty sure you wouldn't understand it if you could read it. That is why there are people who write articles like the one in Wired.