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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.'"
Ohm-mani-padme-hum
When I'm in a quiet room I can often hear a quiet hum. It started after I went to an Arctic Monkeys concert...
Matthew Sparkes
I've always just assumed it was the Earth purring.
Nothing is impossible. We just haven't quite worked out how to do it yet.
For the love of God, make it stop!
The opposite of progress is congress
So all this time I guess I should have put the tinfoil in my shoes.
#!
...as Douglas Adams might have said.
All this time, I just assumed it was because it couldn't remember the words.
I think this is a concept related to Pythagoras' Musica Universalis http://en.wikipedia.org/wiki/Musica_universalis. An inaudible sound on all celestial bodies.
I hate signatures
Ok, so the waves are making the sound. Now tell us what causes the waves. I didn't notice a source in TFA.
Just another day in Paradise
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
Take off every 'sig' !!
Your article was very interesting, but it's wrong. I have a better idea. You see, the center of the earth is full of bees. They make the earth hum and the turtle stack keeps turning to find out what's buzzing. You see? Mine's a much better explaination: explains the humming and the rotation of the Earth!
Demented But Determined.
It is probably driving the whales crazy. They think it's the Voices...
Nothing witty
When I shutdown my PC. Turns out the bearing was on its way out.
Task Mangler
They didn't say what causes the waves !
Everybody knows this is Great Cthulhu snoring in his sleep
Now please lose 2D6 sanity points
The Wise adapts himself to the world. The Fool adapts the world to himself. Therefore, all progress depends on the Fool.
...the waves are making the sound.
Wait a minute. How do we know that it's the waves that are causing the hum, and not the other way around? Perhaps the planet is still ringing from meteor impacts, and the hum is just the resonant frequency. The deep ocean waves may be just a side effect.
When our name is on the back of your car, we're behind you all the way!
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.
e cording mentiones only down to 1Hz. Need to see original article in Nature from work.
http://en.wikipedia.org/wiki/Seismometer#Modern_r
I do not believe in karma. "Funny"=-6. Do good and forbid evil. Yours, Oft-Offtopic Flamebaiting Troll.
I always thought it was the Balrog humming.
These atheistic God-denying scientists attribute the constant hum detected by the seismometers to some random wave action at the ocean floors. But they ignore the fact that it violates the second law of thermodynamics (whatever it is). The real cause for the hum is the intelligent shaking by the Shaker. We demand equal time in all classrooms and seminars and conferences, wherever these surfologists congregate to rebut their theory (not fact) with our scientifically formulated real sceintific fact that intelligent shaking is the fundamental cause for all the hum on earth.
sed -e 's/Chuck Norris/Rajnikant/g' joke > fact
If this humming is omnipresent, it means that every music is "sampling" it without authorization. We then sue RIAA out of existence for unlicensed sampling.
PROFIT!
Nobody's figured out how to ground the dang thing.
Post may contain irony: discontinue use if experiencing mood swings, nausea or elevated blood pressure.
Maybe we could build a clock that used this hum as some sort of synchronization. Then every clock on the planet could be synchronized, since this signal is presumably detectable everywhere.
:-)
OK, I didn't say it was a *good* idea
The more you regulate a company, the worse its products become.
Maybe the Earth just doesn't know the words.
You SO win the prize for 'AC reply that is most obviously by the original poster, ever'
A winner is you!
Whence? Hence. Whither? Thither.
We're living inside an inter-galactic boy band.
Venus is the hot one and will turn out to be gay (natch, I mean Venus?)
Earth is the um, down-to-earth one - full of life.
Mars - the cold and distant one - always at war with the other members
Jupiter - slightly overweight - jolly
Saturn - Gaudy over-compensator wears lots of jewelry and rings - looks up to Jupiter
Hot headed Mercury - left in a huff to form his own band - his manager is the real star though.
Uranus was an asshole and left before fame came.
Neptune - always blue, committed suicide after what happened to Pluto...
Pluto? Well, Pluto was thrown out when it was discovered he never could sing.
Cake or Death? Cake Please!
All objects have a mean frequency which in this example is causing the frequency that they are observing in the water. The frequency in the water comes from the planet's own resonance, or a harmony thereof.
Tesla noticed this and build a little tool which hit on the harmonic frequency and kept accelerating the oscillation with a device he built until there were "earthquakes" observed all around, and he had to cut short a trip to run home and turn it off. Indeed in manufacturing speakers you try to get this frequency down below audioble range as you don't want the speaker to resonate and alter the sound it's supposed to generate.
It's a very common mistake made by many when they observe a symptom (not realizing there is a real why behind it.)
Article reporting the milliHz hum in 1998
IDA (International Deployment of Accelerometers) used to detect the hum.
Article in Nature (1979) assesses if IDA can be used to detect very low frequency seismic data. Looking at the figure 1 of amplitude(?) ("MD counts" at Rarotonga station not shown on the current IDA map) I can see the aftershocks in 2 hour intervals after the Indonesia earthquake, but the subj frequencies could be detected only by obtaining the spectrum (Fig.2) at mHz range which frankly looks like white noise - irregular beats.
Most interesting figure is Fig.3 which shows the 0.43-0.52mHz of the _processed_ spectrum measured at six different stations around the world at Hour 25 and on. The Alaska station (CMO) has much clearer spectrum compared to the closest (?) RAR station.
All of it must have meant something for a seismologist which I am not.
I do not believe in karma. "Funny"=-6. Do good and forbid evil. Yours, Oft-Offtopic Flamebaiting Troll.
A key breakthough was figuring out how to locate continuous signals. For normal earthquakes you have a sharp beginning. Using four or more seismographs you can invert for x,y,z and t0 (called triangulation).
For continuous signals you can find source by cross-corelating long pieces of signal from multiple locations. I first saw this in ambient noise submarine location, but the seismologists have now adopted it for analyzing some kinds of difficult signals like hum.