Earth's Constant Hum Explained

MattSparkes writes "It has been known for some time that there is a constant hum that emanates from the Earth, which can be heard near 10 millihertz on a seismometer. The problem was that nobody knew what caused it. It has now been shown that it is caused by waves on the bottom of the sea, and more specifically 'by the combination of two waves of the same frequency travelling in opposite directions.'"

Comments

Re:10 millihertz

[FormOfActionBanana]

Actually, I think it works out to about 36 waves per hour.

10 milliHertz = 10 * 1/1000 waves per second
=> 0.01 waves per second
* 60 => 0.6 waves per minute
* 60 => 36 waves per hour

hertzs

[mapkinase]

10 milliHz is a beat every 100 seconds. Must be really tricky to detect. I wonder how far below that frequency the sensitivities of seismometers go.

http://en.wikipedia.org/wiki/Seismometer#Modern_re cording mentiones only down to 1Hz. Need to see original article in Nature from work.