The Planet's Hum: 'Japanese researchers have been studying a mysterious hum, emitted by Planet Earth as its geological and atmospheric events combined 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 the pitches of the 50 notes range between two and seven millihertz- about sixteen octaves below middle C. They said that the individual notes sound pleasant enough, but combined they are like endless banging on a trash can. They advise that it would be 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 not actually the sound of seismic or weather events, but is the lingering echo of their combined occurences.'

© 1999 Earth Environment Services