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Ocean Currents Proposed As Cause of Magnetic Field

kdawson posted more than 5 years ago | from the round-and-round-and-round-in-the-circle-game dept.

Earth 333

pjt33 notes a recently published paper proposing that ocean currents could account for Earth's magnetic field. The wrteup appears on the Institute of Physics site; the IOP is co-owner, with the German Physical Society, of the open-access journal in which the paper appears. This reader adds, "The currently predominant theory is that the cause of Earth's magnetic field is molten iron flowing in the outer core. There is at present no direct evidence for either theory." "Professor Gregory Ryskin from the School of Engineering and Applied Science at Northwestern University in Illinois, US, has defied the long-standing convention by applying equations from magnetohydrodynamics to our oceans' salt water (which conducts electricity) and found that the long-term changes (the secular variation) in the Earth's main magnetic field are possibly induced by our oceans' circulation."

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First post (-1, Offtopic)

Anonymous Coward | more than 5 years ago | (#28329597)

You may be attracted to Slashdot, but you'll be repelled by my first post!

First magenetic field causing trout! (-1, Offtopic)

Anonymous Coward | more than 5 years ago | (#28329607)

I am a FISH!

Could be... (4, Interesting)

houstonbofh (602064) | more than 5 years ago | (#28329609)

There is enough junk floating on the oceans that the currents could be ferrous.

Re:Could be... (2, Funny)

arctanx (1187415) | more than 5 years ago | (#28329785)

So we're talking about _electric_ ocean currents? How is right hand rule newsworthy?

Re:Could be... (5, Funny)

fahrbot-bot (874524) | more than 5 years ago | (#28330071)

So we're talking about _electric_ ocean currents? How is right hand rule newsworthy?

Um, this is /. so I'm not sure "right-hand rule" always means what you think it does here. :-) I'm sure a lively debate could ensue on "science geek" vs. "lonely geek".

Re:Could be... (4, Funny)

Anonymous Coward | more than 5 years ago | (#28330093)

Lonely geek has moved on to the Fleshlight rule.

Re:Could be... (2, Funny)

Anonymous Coward | more than 5 years ago | (#28329841)

So are you saying the ocean is a ferrous wheel?

Especially when we keep crashing planes into them (4, Funny)

atmurray (983797) | more than 5 years ago | (#28330111)

Too soon?

Polarity switch (4, Funny)

indre1 (1422435) | more than 5 years ago | (#28329621)

So basically we know that global warming has taken over our ocean's currents when our compasses start pointing to the south...

Re:Polarity switch (0)

Anonymous Coward | more than 5 years ago | (#28329669)

Well, the magnetic south pole, yes.

Re:Polarity switch (3, Interesting)

Anonymous Coward | more than 5 years ago | (#28330115)

It'll be the magnetic North pole... North just wont be where you think it is.

Re:Polarity switch (4, Informative)

Killer Orca (1373645) | more than 5 years ago | (#28330129)

No, the poles already reversed once in theory http://en.wikipedia.org/wiki/Earth's_magnetic_field [wikipedia.org] , and are likely to keep reversing, though none of us will be around to find out.

Re:Polarity switch (1)

mustafap (452510) | more than 5 years ago | (#28330269)

>and are likely to keep reversing, though none of us will be around to find out.

And I doubt that the people around at the time will be around to find out either :o)

Re:Polarity switch (2, Funny)

atheistmonk (1268392) | more than 5 years ago | (#28330359)

What we need to do is reverse the polarity of the neutron flow.

But this would mean?!?!?!?!? (0)

Anonymous Coward | more than 5 years ago | (#28329645)

The Core was just a bunch of non-scientific crap.

Re:But this would mean?!?!?!?!? (1)

Gravedigger3 (888675) | more than 5 years ago | (#28329675)

What was it before?

Re:But this would mean?!?!?!?!? (3, Funny)

interkin3tic (1469267) | more than 5 years ago | (#28329749)

What was it before?

A coffee coaster.

Re:But this would mean?!?!?!?!? (0)

Anonymous Coward | more than 5 years ago | (#28330219)

What was it before?

The results of a null pointer dereference.

Re:But this would mean?!?!?!?!? (5, Insightful)

larry bagina (561269) | more than 5 years ago | (#28329753)

The magnetic field is believed to prevent solar wind from eroding water and oxygen. If ocean water creates a magnetic field that prevents water from eroding .... that's a serious chicken/egg problem. FWIW, Mars used to have water and may have at one point had a stronger magnetic field than the Earth. It currently has a weak magnetic field and negligible water. Mars doesn't have a large moon to create tides, either.

Re:But this would mean?!?!?!?!? (1, Informative)

Anonymous Coward | more than 5 years ago | (#28330205)

I wasn't aware water really responded much to solar radiation. Aren't some spaceship plans built with water used as shielding against solar flares? Water is pretty darn stable. There's lots of water ice in comets, and Mars probably does have lots of water, it's just ice.

Re:But this would mean?!?!?!?!? (3, Informative)

Gerzel (240421) | more than 5 years ago | (#28330633)

Yes exactly water ice in comets. Do you know what a comet's tail is made out of? Water evaporated and removed from the comet by solar radiation.

I may be wrong, Im not an astrologer (4, Interesting)

edittard (805475) | more than 5 years ago | (#28329659)

Aren't there planets that do have magnetic fields, but don't have oceans? And aren't there moons that are the opposite case?

Re:I may be wrong, Im not an astrologer (5, Funny)

gardyloo (512791) | more than 5 years ago | (#28329757)

I can pretty much guarantee that astrologers would have no idea what you're talking about :)

Re:I may be wrong, Im not an astrologer (-1, Offtopic)

Anonymous Coward | more than 5 years ago | (#28330157)

At a small air terminal in the Texas Panhandle, three strangers are awaiting their shuttle flight. One is a Native American passing through from Oklahoma. Another, a local ranch hand on his way to Ft. Worth for a stock show. The third passenger is an Arab student, newly arrived at the Texas oil patch from the Middle East.

To pass the time they strike up a conversation on recent events, and the discussion drifts to their diverse cultures. Soon the Westerners learn that the Arab is a devout Muslim. The conversation falls into an uneasy lull. The cowpoke leans back in his chair, crosses his boots on a magazine table, tips his big sweat-stained hat forward over his face. The wind outside blows tumbleweeds and the old windsock flaps, but no plane comes.

Finally, the Native American clears his throat and softly, he speaks: 'Once my people were many, Now we are few.' The Muslim raises an eyebrow and leans forward, 'Once my people were few,' he sneers, 'and now we are many. Why do you suppose that is?' The Texan shifts the toothpick to one side of his mouth and from the darkness beneath his stetson says, 'That's 'cause we ain't played Cowboys and Muslims yet.'

Re:I may be wrong, Im not an astrologer (-1, Troll)

arminw (717974) | more than 5 years ago | (#28330165)

....I can pretty much guarantee that astrologers would have no idea what you're talking about....

Current scientists have no better idea and don't truly know what makes the earths magnetic field. My assertion that God just created it that way, so that we could live upon the earth and worship him is just as valid. Scientists think they know how our world works, but the more answers they get, the more questions they get as well and so they are not much further ahead than our ancestors. Despite all of our technology, we still have not learned to live in peace with one another but have made Weapons of Mass Destruction which to possibly annihilate the entire human race.

Re:I may be wrong, Im not an astrologer (-1, Flamebait)

Anonymous Coward | more than 5 years ago | (#28330203)

Wow! You must be incredibly proud of your ignorance.

Re:I may be wrong, Im not an astrologer (0)

sumdumass (711423) | more than 5 years ago | (#28330289)

Why, he telling the truth of the situation, there is no particular evidence backing the scientific claims outside of rationed self justification.

On another note, I don't believe he said he believed that god did anything, he said that it was just as valuable as the current explanation. Either way, it's like gravity, we don't know exactly how to product it, what caused it, or how to recreate it but we know it is there and can use it for out benefit just like the magnetosphere.

Anyways, the study's importance doesn't really mean that the oceans cause the magnetic field, more so as it is interacting with it and there are common effects with each. Perhaps there are more then one way to have a magnetic field and we are just understanding one of them.

Re:I may be wrong, Im not an astrologer (1)

Brian Gordon (987471) | more than 5 years ago | (#28330419)

The tenets of an ancient religion are as valuable as a plausible educated guess?

And this situation is completely different from gravity. We know exactly how gravity behaves and can model it perfectly (well, until you get down to the quantum level). We just don't have a very good way to break it down like we've been able to do with the other 3 fundamental interactions. In the case of the Earth's magnetic field, we don't know what generates it and we don't know why it changes direction, but there's nothing magic or fundamental going on like with gravity; it's just a difficult problem in geology.

Re:I may be wrong, Im not an astrologer (1)

DJRumpy (1345787) | more than 5 years ago | (#28330475)

Actually there is no proof at all that God exists (read: 'faith'). There is plenty of mathematical evidence to explain gravity. We may not be able to reproduce it directly, but it is most certainly measurable and quantifiable.

The theory of gravity is just that. A theory [nebscience.org] . It has gone beyond a hypotheses.

Unless something more 'provable' comes along, it will remain the dominant theory. It's unlikely that 'God's Gravity Hypothesis' will oust it any time soon.

Re:I may be wrong, Im not an astrologer (1)

gardyloo (512791) | more than 5 years ago | (#28330481)

On another note, I don't believe he said he believed that god did anything, he said that it was just as valuable as the current explanation.

      You may be right about the first point. However, reading some of his other postings on slashdot, he seems to take every opportunity to get some mention of a creator shoved into his comments, and I'd be willing to bet that this time is no different.
      As to the second point, if he really was saying that, it's a big Logic: Ur doin it rong failure on his part.

Re:I may be wrong, Im not an astrologer (0)

Anonymous Coward | more than 5 years ago | (#28330271)

The correct reaction to a question is to look for a rational answer, not to say "ghost man inna sky dunnit!"

Re:I may be wrong, Im not an astrologer (5, Informative)

Creepy Crawler (680178) | more than 5 years ago | (#28329775)

That's correct. According to their theory, moons like Europa should have a rather strong magnetosphere.

Europa is believed to have a warm, salty ocean under the ice crust. And yet, it shows only slight inducted magnetic field from Jupiter. Contrast that with Ganymede, the only moon with its own magnetosphere and a liquid iron core. Satellite photos dont show very much (or any) water on its surface.

Hmm.

Re:I may be wrong, Im not an astrologer (2, Insightful)

Gravedigger3 (888675) | more than 5 years ago | (#28329807)

My question is how the hell can they determine all this information about other planets when we can't even figure out exactly what makes our own planet tick?

Re:I may be wrong, Im not an astrologer (4, Interesting)

Creepy Crawler (680178) | more than 5 years ago | (#28329857)

The idea of the ocean under Europa is that of an educated guess based upon tidal forces between Jupiter, and the fact that surface composition of Europa is frozen water. Flyovers have taken spectral pictures indicating that fact. They also have taken magnetic force readings and determined that any form of magnetosphere was Jupiters creating.

Ganymede has a liquid iron core, from which I dont understand how they figured that out. However, many sources say so, including NASA. And it's noted by the natural color of 'streaking on the ice' that the moon does have its own magnetosphere. And it was measured by Flyovers. It's strange that it still has a liquid iron core, al most over planets have frozen. The assumption is that Jupiter tidal forces have insulated it.

We dont need to understand why and how a liquid iron core creates a magnetosphere. We CAN measure more data points to see if our hypothesis matches with known facts. And this water-creates-magnetosphere seems debunked.

Re:I may be wrong, Im not an astrologer (4, Interesting)

Korin43 (881732) | more than 5 years ago | (#28330653)

I wonder if the idea that Ganyemede has a liquid iron core is based on the assumption that only liquid iron cores cause magnetic fields?

Re:I may be wrong, Im not an astrologer (1)

im_thatoneguy (819432) | more than 5 years ago | (#28329827)

Europa's ocean may not have strong currents though. Also there could be multiple causes that don't match every planet. Our sample size is pretty small on the subject. Ganymede might have a magnetic field due to its liquid iron core. And we might have a magnetic field due to our oceans. And Planet X might have a magnetic field due to something else all together.

Re:I may be wrong, Im not an astrologer (4, Funny)

VampireByte (447578) | more than 5 years ago | (#28329799)

I may be wrong, Im not an astrologer...

If you ask an astrologer a question about the ocean, they'll probably want to know if you're a pisces.

Re:I may be wrong, Im not an astrologer (2, Informative)

Bungie (192858) | more than 5 years ago | (#28329901)

Aren't there planets that do have magnetic fields, but don't have oceans?

IIRC Venus has a weak magnetic field and does not have an ocean.

Re:I may be wrong, Im not an astrologer (3, Informative)

icebike (68054) | more than 5 years ago | (#28330139)

As does mars. It has a weak field, but it also is suspected of having a much smaller molten core.

Europa and Ganymede have molten cores due to gravitational churning.

So far, molten cores correlate well with magnetic field strength. Oceans, when present, tend to be on those bodies having molten cores, but their absense does not entirely preclude a magnetic field.

Re:I may be wrong, Im not an astrologer (4, Informative)

Iron Sun (227218) | more than 5 years ago | (#28329921)

Mercury has a magnetic field, which quite surprised planetary scientists when it was first discovered by MAriner 10, as the prevailing theory at the time was that Mercury's small size would have led to its core solidifying by now and stopping the dynamo that generated the field.

There's obviously a lot we don't know about planetary magentic fields, and I wouldn't want to judge the entire theory just by something I read on Slashdot, but I find it hard to understand how oceanic currents could account for Earth's magnetic field but not for Mercury's.

Re:I may be wrong, Im not an astrologer (1)

defireman (1365467) | more than 5 years ago | (#28329933)

Depends. But lacking an ocean will not preclude a planet from getting an magnetic field - there could be other factors at work here.

Re:I may be wrong, Im not an astrologer (1)

MrMista_B (891430) | more than 5 years ago | (#28330207)

Yes. Fortunately, as usual, the summary has /nothing to do/ with the /actual/ article that it's referencing.

Uh, right. (3, Insightful)

pclminion (145572) | more than 5 years ago | (#28329691)

Yeah, that makes a whole hell of a lot of sense. Why not invent some brand new, goofy theory that applies only to the Earth and not to any of the other celestial bodies that we know have magnetic fields which DON'T have oceans? Has somebody never heard of Occam's Razor? Instead of one theory which works to explain all magnetic fields on all celestial bodies why not invent something stupid for no good reason?

Re:Uh, right. (4, Insightful)

MrMista_B (891430) | more than 5 years ago | (#28329719)

Because the other theory hasn't been tested, and might be wrong.

Ignoring possible alternative theories, especially for unknowns, is no different from adhering to dogma on pure faith alone, and damages scientific inquiry.

Re:Uh, right. (0)

Anonymous Coward | more than 5 years ago | (#28329755)

Well... that's a pretty good reason.

Re:Uh, right. (5, Informative)

pclminion (145572) | more than 5 years ago | (#28329787)

Because the other theory hasn't been tested, and might be wrong.

The point is that the chances that each celestial body's magnetic field is due to a unique generator are... Well, let's say that that is not what we typical see in scientific history. Similar effects are generated by similar causes, especially at planetary scales.

(I see that I've been misled by the summary, as usual. Yes, I should RTFA. But the editors should fucking WTFS in a manner resembling responsible journalism. Could currents in the oceans modulate the magnetic field? Worth investigation, I think.)

Re:Uh, right. (1)

contrapunctus (907549) | more than 5 years ago | (#28329899)

I propose the aether is responsible.

Re:Uh, right. (0)

Anonymous Coward | more than 5 years ago | (#28330053)

I just heard a voice from the aether. It said that it's not.

Joke or not,,, I was trying to think of other mean (2, Insightful)

way2trivial (601132) | more than 5 years ago | (#28330077)

the general argument here is that other planets lacking oceans also have magnetic fields-- so that ain't right..

so I'm thinking, what do all solar bodies have in common that could be another means to that end

solar wind? the flow of all the radiation from the sun, wrapping around the planet, and blowing on? happens to all objects in the system??

Re:Uh, right. (1)

MrMista_B (891430) | more than 5 years ago | (#28330181)

True, true, and I admit I was also misled by the misleading, inflammitory summary. Such is Slashdot these days, I suppose.

Re:Uh, right. (-1, Flamebait)

Anonymous Coward | more than 5 years ago | (#28330043)

Ignoring possible alternative theories, especially for unknowns, is no different from adhering to dogma on pure faith alone, and damages scientific inquiry.

Oh, you mean just like how the global warming zealots try to discredit anyone who doubts anthropogenic global warming, a.k.a. climate change, because "the debate is over" and we "have a consensus"?

Because someone has to respond to trolls (5, Insightful)

Anonymous Coward | more than 5 years ago | (#28330201)

Funny words from someone who used rather massive ad hominem by trying to label people disagreeing with him as zealots.

Consensus is used as an argument because not all of us can be climate scientists. There is large consensus among them that global warming is happening and caused by men. Not all agree to that. Name any theory and you have people who disagree with it. Hell, there is even a flat earth society. But big majority of the expert who know about the subject and have studied it their whole lives believe so.

Most of the people who argue about it in the internet aren't climate scientists. They've read a few stories which have quoted some climate scientists who disagree with the mainstream and then begin arguing. To them I can always answer "Hey, I am not an expert in the field. And honestly, most likely you aren't either. When your arguments are good enough that they manage to sway opinions of the expert, then you can come back to me. Otherwise I have all the reason to assume that there is some flaw in them."

All of us who aren't experts in every field of science have to do that about some subjects. Trust the scientific method and through that, the experts who employ it.

Re:Uh, right. (1, Funny)

Anonymous Coward | more than 5 years ago | (#28330315)

Are you suggesting we remove all water to test this hypothesis?

Re:Uh, right. (1)

interkin3tic (1469267) | more than 5 years ago | (#28329739)

Why not invent some brand new, goofy theory that applies only to the Earth and not to any of the other celestial bodies that we know have magnetic fields which DON'T have oceans? Has somebody never heard of Occam's Razor?

Better question: Is somebody misinterpreting Occam's Razor? The answer is "yes: pclminion."

Re: Uh, right. (4, Funny)

sakdoctor (1087155) | more than 5 years ago | (#28329761)

Occam's Razor was the razor to own. Then the other guy came out with a three-blade razor. Were we scared? Hell, no. Because we hit back with a little thing called the Occam's Razor Turbo. That's three blades and an aloe strip. For moisture. But you know what happened next? Shut up, I'm telling you what happenedâ"the bastards went to four blades. Now we're standing around with our cocks in our hands, selling three blades and a strip. Moisture or no, suddenly we're the chumps. Well, fuck it. We're going to five blades.

Re: Uh, right. (2, Funny)

interkin3tic (1469267) | more than 5 years ago | (#28329825)

I like it, occam's razor turbo:

"Of several acceptable explanations for a phenomenon, the simplest is preferable even when there's good evidence to suggest a more complex explanation and no evidence to suggest the simplest. Furthermore, that evidence is automatically invalidated by the first guy to yell out 'Occam's razor,' especially when the guy makes no attempt to explain himself."

Re: Uh, right. (1)

doublebackslash (702979) | more than 5 years ago | (#28330019)

^_^ That was a good onion article, that one was.
[theonion.com] http://www.theonion.com/content/node/33930 [theonion.com]

By the by, when did the onion open up their archives? I recall them shuffling articles out of their free page very quickly.

Re:Uh, right. (3, Insightful)

physicsphairy (720718) | more than 5 years ago | (#28329837)

According to the article, there is no direct evidence for the metal currents which allegedly induce the magnetic field. They are inferred on basis of the existence of the field. Venus doesn't have a magnetic field--so we decide it doesn't have a molten iron core. The only reason the 'present theory' is so simple and explanatory is because we arbitrarily decide on the planets' internals are such that our theory is always guaranteed to fit.

Your generalization is also a bit off, as plenty (probably most) of the large celestial objects have magnetic fields but lack iron cores. The sun certainly lack an iron core. We assume Jupiter's magnetic field is supplied by metallic hydrogen, but it could just as easily support it by electrical currents.

The magnetic fields are actually quite complex and Occam's razor doesn't mean assuming everything is a perfect sphere, as the classic joke goes. If the oceanic theory successfully explains secular variation then Occam's razor may be more likely to back the ocean theory than the dynamo theory.

Re:Uh, right. (1)

im_thatoneguy (819432) | more than 5 years ago | (#28329889)

I am neither a geophysicist nor am I an oceonographer nor am I any sort of natural scientist. BUT there is a place for this sort of theory. You're essentially advocating the watchmaker theory.

"Since all sophisticated machine whose origins we have observed are by an intelligent creator all sophisticated machines are therefore created through intelligent design."

The alternate scientific theory is that "While intelligent designers do create things (including potentially life) we think the more likely explanation free of unnecessary supposition is natural Evolution."

Occam's razor in this case is not necessary because as TFA states we don't necessarily have proof of a molten iron dynamo. Therefore there could be multiple causes of magnetospheres and on earth our cause might not be the same as on other planets.

I wouldn't give this theory as strong of a likelihood but it's certainly not an superfluous claim subject to Occam's razor just an alternate one.

Re:Uh, right. (1)

Latinhypercube (935707) | more than 5 years ago | (#28330079)

Agreed this sounds wrong, especially with no proof. Surely a giant spinning iron core would produce a much stronger field. Like a dynamo http://en.wikipedia.org/wiki/Dynamo [wikipedia.org]

Re:Uh, right. (0)

sumdumass (711423) | more than 5 years ago | (#28330487)

I have read you other replied and don't wish to contend the premise of your statement, but I need to ask you, what happened when Occam's Razor is wrong?

I know it leaves a provision for being wrong within the application itself but swearing by it could leave something important out of the picture.

Let me explain this a little in laymens terms that everyone can understand and i would like you hear your thoughts on it. Ok suppose we are attempting to figure out how to make some dinner dish that mom used to make before she passed away. The end product is home made bread. The ingredients are flour, water, salt, yeast, and perhaps a pinch of sugar to help set the yeast off. We mix them all, together, let knead, let rise, punch down, knead, shape, and let rise in the pan before baking. That's the simplest, easiest way to make bread which would follow Occam's Razor. Now what if it didn't turn out like moms, still edible and good, but not quite the same. Lets suppose this is because mom let the doe rise three times and lined the bread pan with olive oil and sprinkled a butter substitute on top of it instead of just greasing the sides with butter. In one hand, we have a general explanation. In the other, we have more complicated steps that fail Occam's Razor when we are looking at the smallest detail.

Now, I hoped that was an overly simplified explanation to what I meant by when Occam's Razor is wrong. It could be hundreds of years before something else is discovered and the simplest explanation no longer works where looking at the more complicated explanations sooner could result in more useful knowledge.

New possibilities in terraforming? (3, Insightful)

Kleebner (533168) | more than 5 years ago | (#28329693)

Fascinating! If true, I wonder how it could effect theories on terraforming. If we got enough open and moving water on Mars could it then develop the field needed to block solar radiation and trap an atmosphere?

Re:New possibilities in terraforming? (1)

jd (1658) | more than 5 years ago | (#28330311)

If it's true, then think more in terms of terror forming. The Earth's ocean currents are showing some dramatic changes as a result of global warming.

Re:New possibilities in terraforming? (1)

DerekLyons (302214) | more than 5 years ago | (#28330381)

Which is an interesting question - because it's currently believed that loss of the magnetic field cause the loss of atmosphere and the subsequent loss of water on Mars.
 
Failing to explain Mars represents a major hole in this theory.
 
Failing to explain why the Earth's magnetic fields are more-or-less symmetrical, which the core is and the oceans aren't, is another major problem.

Summary wrong: Oceans only small variations (5, Informative)

Anonymous Coward | more than 5 years ago | (#28329697)

The Slashdot summary is totally wrong.

From the abstract of the paper: "I propose a different mechanism of secular variation: ocean water [...] as it flows through the Earth's main field may [...] manifest itself globally as secular variation."

Meaning: There is a major magnetic field that comes from the molten core. However, certain variations that are as yet unexplained may not result from core phenomena, but from the ocean currents.

I find this much more believable than the swill in the slashdot summary.

Re:Summary wrong: Oceans only small variations (3, Informative)

Gravedigger3 (888675) | more than 5 years ago | (#28329763)

Its not totally wrong.

FTA: "While Ryskinâ(TM)s research looks only at long-term changes in the Earthâ(TM)s magnetic field, he points out that, âoeIf secular variation is caused by the ocean flow, the entire concept of the dynamo operating in the Earthâ(TM)s core is called into question: there exists no other evidence of hydrodynamic flow in the core.â"

He does go so far to say that there is no examinable proof of a liquid core and that we could have been wrong all these years.

It doesn't seem too far fetched for me, but I'll leave the proof to the geomagnetism community.

Re:Summary wrong: Oceans only small variations (1, Informative)

Anonymous Coward | more than 5 years ago | (#28329849)

Well, but saying that a dynamo process in the core may not be happening is not the same as claiming that the oceans are doing it. The paper does not actually say what might replace the dynamo model, but obviously the oceans cannot generate a primary field. They can manage the secular variations by moving in the main field, but those are a factor of 1000 weaker than the persistent field.

Re:Summary wrong: Oceans only small variations (5, Insightful)

CheshireCatCO (185193) | more than 5 years ago | (#28329995)

He says,

If secular variation is caused by the ocean flow, the entire concept of the dynamo operating in the Earthâ(TM)s core is called into question: there exists no other evidence of hydrodynamic flow in the core.

--From the article

Er, dude, no. We are pretty certain that the outer core is a liquid from seismic wave data. "So what?" you say, "Couldn't the core not be flowing?" Perhaps, but our understanding of how heat moves in a fluid is pretty good. And we know that at some point, in order to move the heat out, the fluid has to convect (as the dynamo model requires). So while we haven't directly measured the flow of fluid in the core, arguing that it isn't happening requires at least some explanation of the lack of convection we have every reason to expect.

That said, let's look at the notion that the oceans are responsible. This ought to be measurable if it's worth talking about. We can get close enough to the oceans that we should easily be able to measure variations in the local field due to the oceans. Heck, tides and changes in circulation patterns ought to manifest temporal variations that we could measure. No, I don't know that anyone has done these measurements, I would be a bit surprised if no one had. (In fact, if no one has, I ask: why hasn't the author?)

Also, I'm skeptical by comparison to Europa. That body is in a changing magnetic field that is much more powerful than Earth's (and which changes much more rapidly, every 11 hrs). The ocean required to produce the induced field has something like 3 times (from memory) the salinity of our ocean and only produces a response of ~100 nT. (Our magnetic field is around 50 mT.) I'm... skeptical.

Re:Summary wrong: Oceans only small variations (1)

DerekLyons (302214) | more than 5 years ago | (#28330389)

He does go so far to say that there is no examinable proof of a liquid core and that we could have been wrong all these years.

While there is no proof you can put your finger on - rejecting a hypothesis supported by other evidence without providing a replacement for that hypothesis is pretty dodgy science.

Re:Summary wrong: Oceans only small variations (0)

sumdumass (711423) | more than 5 years ago | (#28330541)

I don't think the evidence for a liquid core is much more then the magnetic fields and the secular variations and anomalies there. There is supporting evidence of the effect but as far as I know, that cause is only supported by the effect. Pointing out that it could be caused by the ocean in so much as the variations does remove more all of the proof of a molten core, but it also replaces it with the ocean theory.

Headline is a Lie (1)

MrMista_B (891430) | more than 5 years ago | (#28329875)

Read above.

Ocean currents are /NOT/ being proposed as a cause of the magnetic field.

The headline is a lie.

Re:Summary wrong: Oceans only small variations (1)

syousef (465911) | more than 5 years ago | (#28330089)

I find this much more believable than the swill in the slashdot summary.

Take a look at who submitted it. PEBKAC.

Re:Summary wrong: Oceans only small variations (3, Informative)

RobVB (1566105) | more than 5 years ago | (#28330117)

A few interesting links with more info about these subjects:

http://gsc.nrcan.gc.ca/geomag/field/sec_e.php (about secular variation)

http://en.wikipedia.org/wiki/Magnetic_declination (about magnetic declination, obviously)

Long story short, magnetic declination is the difference between the geographical North Pole and the apparent magnetic North Pole at any one place on earth. The secular variation they're talking about is the gradual change in that magnetic declination, or the apparent movement of the Earth's magnetic North Pole. Secular variation is usually between 0 and 15 arcminutes per year - specific example: a nautical chart of the Thames Estuary from 2008 lists a yearly secular variation of 8' (arcminutes) Eastward.

Re:Summary wrong: Oceans only small variations (1)

mapkinase (958129) | more than 5 years ago | (#28330373)

"The Slashdot summary is totally wrong." that's kdawson for you

Makes as close as to no sense as possible (0)

Anonymous Coward | more than 5 years ago | (#28329705)

Bunk.

Wouldn't explain magnetized rocks, magnetic north, etc...

Simply solved (1)

Creepy Crawler (680178) | more than 5 years ago | (#28329723)

Well, relativity simply solved.

All we need to do is find an object that has a magnetosphere and no aqueous sea.

How about the Sun?

Re:Simply solved (2, Insightful)

Lupulack (3988) | more than 5 years ago | (#28329821)

The sun doesn't appear to have much in the way of flowing iron at its core either. Does that mean that it can't have a magnetic field?

Essentially the theory stands at : flows of conductive fluid ( salt water, iron, plasma ) can generate magnetic fields. We have no evidence that there is flowing iron in the earth's core, but we have rather a lot of flowing salt water. Hmmm...

Re:Simply solved (0)

cyn1c77 (928549) | more than 5 years ago | (#28330091)

The sun doesn't appear to have much in the way of flowing iron at its core either. Does that mean that it can't have a magnetic field?

Essentially the theory stands at : flows of conductive fluid ( salt water, iron, plasma ) can generate magnetic fields. We have no evidence that there is flowing iron in the earth's core, but we have rather a lot of flowing salt water. Hmmm...

Ummmm, we do have some pretty strong evidence that the sun has iron at its core. If you believe in things like spectroscopy and archival meteorite data, then the sun is about 0.2% iron. And if you believe in gravity, then most of that iron is near the center of the sun, which is more than 300,000 times heavier than earth, so yeah, that's a lot of iron. Of course, the sun also has no solid crust and also has nuclear fusion occurring inside it, so maybe it isn't a good comparison body.

Why do you not believe that there is flowing iron at the Earth's core? Scientists have shown that there is a liquid layer of material beneath the material by studying the transmission of P and S waves generated from earthquakes. Do you not believe that the core of earth contains iron? Because the paper's author disagrees with you. He just doesn't believe that the flowing iron at the core is the only source the magnetic field.

Re:Simply solved (1, Interesting)

Lupulack (3988) | more than 5 years ago | (#28330167)

I didn't say there was no iron at the core of the sun, only that there wasn't a great deal of it, at least in comparison.

And to quote the article linked, ''If secular variation is caused by the ocean flow, the entire concept of the dynamo operating in the Earth's core is called into question: there exists no other evidence of hydrodynamic flow in the core.''

So the only evidence of flowing iron at the earth's core causing the earth's magnetic field is ... the existence of the earth's magnetic field itself. That's a bit circular, isn't it?

Re:Simply solved (1)

CheshireCatCO (185193) | more than 5 years ago | (#28329931)

Better example: Mercury.

Re:Simply solved (1)

Progman3K (515744) | more than 5 years ago | (#28330195)

The sun has a sort of liquid... Plasma...
Of course the summary for the article is wrong, so we can just make up stuff if we want to.

Ahah! (0, Offtopic)

XPeter (1429763) | more than 5 years ago | (#28329791)

He predicted Global Warming...shocked the world with "An Inconvinient Truth"...and created the internet.

This can only mean one thing: Al Gore is the Messiah. Move over Obama, there's a new kid in town.

What happens when Ocean current patterns change? (0)

Anonymous Coward | more than 5 years ago | (#28329893)

While I have no expertise in this area ... Are ocean current patterns really as static as the Earth's magnetic field? I'd think that there would be more fluctuations/variations in the Earth's magnetic field if it depended on the waterbodies. Wouldn't this also require compasses / magentic fields being disrupted when there are earthquakes/tsunamis or major storms?

Re:What happens when Ocean current patterns change (2, Informative)

osu-neko (2604) | more than 5 years ago | (#28330357)

While I have no expertise in this area ... Are ocean current patterns really as static as the Earth's magnetic field?

Yes. Neither are static, both change continuously, but both are relatively slowly changing phenomena.

I'd think that there would be more fluctuations/variations in the Earth's magnetic field if it depended on the waterbodies.

On geological timescales, it would change dramatically. Which, we know, it does.

Wouldn't this also require compasses / magentic fields being disrupted when there are earthquakes/tsunamis or major storms?

No, since large-scale ocean currents are not noticeably affected by these things.

Just last night... (4, Interesting)

Anachragnome (1008495) | more than 5 years ago | (#28329939)

Just last night there was an interesting show on television that focused on the subject of magnetic fields associated with planets.

There was an experiment covered in the show that was essentially a large, hollow orb filled with liquid sodium (a substitute for the iron at Earth's outer core. It is impossible to reproduce the pressure and heat of our Earth's guts in such a small scale experiment) which was then spun at a comparatively equal rate to that of Earth. The orb began producing strong magnetic fields.

I somehow doubt that if the same experiment were to be reproduced solely with a thin layer of salt water on the surface (and no sodium inside) that it would produce such strong magnetic fields. That being said, while the thought of Earth's magnetic field being produced solely by the water on the surface is interesting, personally I think it is more then likely a combination of the two factors rather then one alone that produces our protective magnetic field.

In addition, I wonder if the flux in ocean water levels, historically speaking, coincides with the strength and direction of past magnetic fields as recorded in ancient lava flows. If so, this would seem to back up the theory proposed in the article.

Re:Just last night... (2, Interesting)

db32 (862117) | more than 5 years ago | (#28330099)

[Citation Needed]

Seriously...please do. I was aware of the whole molten sodium ball thing because I remember that spinning 13 tons of molten sodium could be a REALLY bad idea. However, the last I saw of it they were still preparing and had not actually done anything yet.

Also...TFA isn't saying the field comes from water, it says variations in the field come from water passing through the main field. In typical /. fashion the summary is nonsensical crap.

It doesn't say ocean currents cause the field (5, Informative)

John Hasler (414242) | more than 5 years ago | (#28329967)

The paper [iop.org] does not say that ocean currents cause the magnetic field. It hypothesizes that ocean currents cause secular variations in the magnetic field.

Re:It doesn't say ocean currents cause the field (0)

Anonymous Coward | more than 5 years ago | (#28330387)

The paper [iop.org] does not say that ocean currents cause the magnetic field. It hypothesizes that ocean currents cause secular variations in the magnetic field.

However the paper concludes with this conjecture: "If the secular variation is caused by the ocean
flow, the entire concept of the dynamo operating in the Earthâ(TM)s core is called into question: there
exists no other evidence of hydrodynamic flow in the core." So while the paper doesn't say it, the author seems to entertain the possibility that currents my be solely responsible for the magnetic field.

Testing, testing... (1)

hyades1 (1149581) | more than 5 years ago | (#28329969)

We might have proof of this in the foreseeable future. If we keep warming up the planet, it's quite possible that one or more major ocean currents will start behaving differently. If that happens and we see a change in the magnetic field, that would provide a strong hint that the two are connected in some way.

A big fish story is circulating into a vortex (1)

itsybitsy (149808) | more than 5 years ago | (#28329971)

Wow, that's quite the fish story. Pretty interesting hypothesis though it needs solid, er, liquid evidence to back it up... otherwise it's flowing into the dust bin, er, drain of science history as a pretty darn cool and silly theory that didn't make it.

Well actually he's saying that there is a "main field" and that the ocean currents are a modification or additional field. Cool. Cutting edge science can be fun. It's where cross currents of ideas and beliefs mix until evidence eventually coalesces with a vortex pulling everyone to the indisputable conclusions - if you're lucky and on course of course.

I wonder if this hypothesis might explain the "magnetic anomalies" in the oceans around the world that are constantly changing? I'd love to see a three dimensional simulation of the raw data collected by the magnetic sensing satellites and the gravity satellites correlated together with ocean current movements.

Does this theory spin the other way in the southern hemisphere?

Pseudoscientists attend! (3, Interesting)

rlseaman (1420667) | more than 5 years ago | (#28329979)

Note how this dishes the favorite argument of pseudoscientists, who always (always, always) claim that the scientific "establishment" refuses to hear evidence that conflicts with accepted wisdom. Rather - to the extent that such an establishment can be said to actually exist - science will entertain any sort of extreme argument, as long as it is cogently - and entertainingly - presented. To overturn competing theories extreme arguments ultimately demand extreme evidence, however.

Re:Pseudoscientists attend! (5, Interesting)

osu-neko (2604) | more than 5 years ago | (#28330405)

Science has always reserved its greatest accolades for those who prove what came before to be wrong, and every scientist in the world knows the best way to become famous is to prove everyone else wrong. Nevertheless, pseudo-scientists always argue that scientists have some vested interest in preserving the current order (and thus dooming their careers into obscurity when they could have become famous Nobel prize winners). This argument has never made any sense, but that doesn't stop them from making it. So, one more example won't make any difference to them -- people who advocate a bad argument that runs counter to evidence are not dissuaded by more evidence.

Winds (3, Funny)

4D6963 (933028) | more than 5 years ago | (#28330033)

Ocean currents? Here's an even better idea : winds! I know it's true because when I throw a fridge magnet in the wind it goes in the same direction. So next time you want to know in what direction the wind is going, just look at a magnetic compass!

Another reason to dig deep... (1)

RobVB (1566105) | more than 5 years ago | (#28330039)

... and I mean that literally. I'm a big fan of space research, but maybe we should also be working on an expedition (or Journey, if you will) to the Centre of the Earth. Or at least find a way to take samples and readings down there. Humanity has never dug deeper than 12,262 meters(*), and although I see the obvious problems in digging for lava, I'm convinced it would yield interesting results.

(*) This number was taken from the following article, about a Russian digging experiment: http://www.damninteresting.com/?p=567

And I'll just post this here too: http://en.wikipedia.org/wiki/Integrated_Ocean_Drilling_Program

Language matters (2, Interesting)

Mr_Chang (1576589) | more than 5 years ago | (#28330041)

"The currently predominant theory ...of Earth's magnetic field"

To be certain, there are NO 'theories' for Earth's magnetism, only a variety of HYPOTHESIS'S.

Once again the term theory is being misused for HYPOTHESIS. It is a great disservice to science and scientists to not understand the definition and implications for both terms.

A worker whose research achieves the level of Theory is among the 'Nobel class' of scientists. Therefore the term should be used properly and with some reverence.

So before we go any further, would someone venture to post the scientific definitions and usage for these two terms, hypothesis and Theory.

Thanx

Does this mean (0)

Anonymous Coward | more than 5 years ago | (#28330145)

That I can no longer believe the science in that truly awesome movie The Core?

Another reason to cut Carbon Emissions. (0)

Anonymous Coward | more than 5 years ago | (#28330179)

Imagine...Global warming melts the polar ice caps, the sea rises, the earths sea currents change which in turn effects the earths magnetic field. What a crazy thought...our pollution could change the direction of North.

Didn't this guy prove it was the molten inards? (1)

BradyB (52090) | more than 5 years ago | (#28330291)

This link to an article on NPR, http://www.npr.org/templates/story/story.php?storyId=90947943 [npr.org] , was also in a short show on the Science Channel about magnetic fields. So, I think that the reader should not state that there is no evidence that the molten inards of the Earth are not the probable cause of our magnetosphere.

Bermuda triangle? (0)

Anonymous Coward | more than 5 years ago | (#28330341)

Could this be an explanation for the Bermuda triangle?

Re:Bermuda triangle? (1)

osu-neko (2604) | more than 5 years ago | (#28330493)

Could this be an explanation for the Bermuda triangle?

I don't think so. There's no reason to expect that the Earth's magnetic field, whether influenced by ocean currents or not, has any impact on the tendency for humans to be superstitious, invent ghost stories, or be gullible to pseudo-science. To the extent that the Bermuda Triangle phenomenon is not fully understood, breakthroughs will need to be made in psychology and sociology, and I for one have high hopes that someday the phenomenon can be largely nullified by good statistics and science education.

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