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.'"

Hmmmmmmmm

[dcw3]

Ok, so the waves are making the sound. Now tell us what causes the waves. I didn't notice a source in TFA.

Re:Whales

[Prune]

This would have been funny, except the ten MILLIhertz frequency (one beat per hundred seconds) is a couple of orders of magnitude lower than what whales can hear.

Re:Why?

[Anonymous Coward]

These are seismologists - the same people who try to predict earthquakes. Any noise the earth makes may have something to do with earthquakes and thus is worth study.

Re:Did ancient greeks know about this?

[kestasjk]

No, Pythagoras didn't have a seismometer capable of detecting 10 millihertz..

Throbbing

[andrewuwe]

10 millihertz sounds more like a throb than a hum to me, perhaps even a chug.

Re:hertzs (stacking)

[Reverse Gear]

Well many seismometers are constantly on and have very long periods of this noise recorded.
So with enough stacking you can pretty much detect as low frequencies as you want if only the amplitude is strong enough to be detected by the seismometers, so my guess is that the limiting factor is not the 1 Hz, but lies in how small amplitudes these seismometers detect.

These suggested waves would hold quite an amount of energy so it does make sense that they are able to detect these to me.

Re:Maybe it's just happy?

[LMacG]

Who said anything about cats?

Re:Maybe it's just happy?

[Aladrin]

Amazingly enough, not all cats are the same. My late tabby only purred when he was happy. Never once did I hear/feel him purr before he received the attention he wanted.

On the other hand, my current cat is the opposite. Purring seems to have nothing to do with being happy. She will frequently walk up to me and just start purring, and generally stops once I start petting her.

So it's not really disinformation, it's partial information. Just like yours.

Re:But wait!

[rucs_hack]

given the fact that most natural systems exist in some kind of homeostatic relationship with other systems, its likely that the cause is rather complex. I wouldn't have a clue where to start.

That's what I love about science though, there's yet another thing to explain. I wonder what it will reveal?

Re:Maybe it's just happy?

[JargonScott]

..and lesbian women becoming sexually attracted to nerds...

Unfortunately they'll be butch instead of lipstick.

Re:But wait!

[Thundersnatch]

given the fact that most natural systems exist in some kind of homeostatic relationship with other systems, its likely that the cause is rather complex. I wouldn't have a clue where to start.

But, you're really quite positive about the whole global warming thing being caused by man, right?

Re:Hmmmmmmmm

[Dorceon]

Considering how litigation-happy that particular church is, you might have considered posting that anonymously.

Re:So that's what causes it

[bhiestand]

Well that begs the question of who is petting it.

No, it doesn't.

Re:On mars the atmosphere shakes once every year

[goombah99]

reference [harvard.edu] and here [washington.edu] and here's a picture of the spare lander that was never launched [washington.edu] the boom on it is the meteorology sensor