Earth Hum

Per the Discovery Channel on Sept. 9 1999, the Earth is emitting a hum. Japanese researchers have been studying a mysterious hum emitted by planet Earth as its geological and atmospheric events combine to produce a frenetic symphony. Naoki Suda and Kaqunari Nawa dredged out the sounds from a mass of seismic data, according to a report in New Scientist,. and say that sound is a mix of 50 notes ranging between two octaves. The pitches are between 2 and 7 MHz - about sixteen octaves below middle C. They said that the individual notes sound pleasant enough, but combined they are like an endless banging on a trash can. The researchers say that it is impossible for anyone to hear them with the naked ear, and the sounds are so subtle that a single magnitude 5.5 quake anywhere on the planet would blot them out. The hum is a natural tone that the Earth makes whenever some seismic or weather event sets it ringing.

Offered by Brian.