Ocean Currents Proposed As Cause of Magnetic Field 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."
Could be... (Score:5, Interesting)
Re: (Score:3, Funny)
Re:Could be... (Score:5, Funny)
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... (Score:4, Funny)
Lonely geek has moved on to the Fleshlight rule.
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So are you saying the ocean is a ferrous wheel?
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Especially when we keep crashing planes into them (Score:4, Funny)
Polarity switch (Score:4, Funny)
Re:Polarity switch (Score:4, Informative)
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>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 (Score:4, Informative)
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.
If you do some non-wiki research, you will find out that Earth's magnetic field has reversed many times over the eons. We're overdue now by several thousand years. This Global Warming may be just another indicator that such a change is imminent.
Re:Polarity switch (Score:5, Informative)
Hundreds if not thousands of direction changes are documented, back into the Triassic at least and possibly into the Late Palaeozoic. There are sufficient that, in more recent times (Cretaceous onwards) the reversal record has been used as a tool for correlation. (Such work may go back further into the geological record ; I've certainly seen it used in Cretaceous mudrock sequences as a petrophysical indicator that can be measured faster and with less skilful operators than other techniques like palynology.)
For certain values of "overdue" ; the distribution of durations between reversal events seems to be essentially random, and since we're over the average duration between reversals, then one could meaningfully "expect" a reversal sooner rather than later. But once you start looking at the statistics, you have to accept that, if the model is accurate, then the probability of a reversal in the next thousand years (say), is the same as the probability of a reversal in the first thousand years after the last reversal. It's the same logic as tossing coins - if you get ten heads in a row, the probability of your next toss being a head is still 1/2, even if the probability of getting 11 heads in a row is 1/2048. Random variables - love 'em or hate 'em, but you can't predict 'em.
That said, outside the statistical description of the record, the physical models suggest that some events seen at the moment (decreasing field strength ; regional anomalies) may be precursors to a reversal.
Has someone been claiming global warming to be related to magnetic field strength? Whooo, can I get a smoke of that? Sounds like good gear.
Re: overdue... for lunch (Score:3, Funny)
We're overdue now by several thousand years.
Not to sound ignorant, but why is it that we're overdue for:
We're overdue for everything, such that, I'm overdue for some coffee.
I know it's Monday morning: don't worry about being late.
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though none of us will be around to find out.
Jesus will be.
Re:Polarity switch (Score:5, Interesting)
Well magnetic north has moved over 1100 kilometers in the past 100 years, and the motion is accelerating. It is currently moving about 40km per year.
Re:Polarity switch (Score:4, Funny)
I"m trying hard to make a joke about writing down when it happened and referring to that as reverse pole-ish notation, but... I think I'll let it go.
(I should probably post this anonymously, but hey - I stand by my bad puns!)
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It'll be the magnetic North pole... North just wont be where you think it is.
I may be wrong, Im not an astrologer (Score:5, Interesting)
Re:I may be wrong, Im not an astrologer (Score:5, Funny)
I can pretty much guarantee that astrologers would have no idea what you're talking about :)
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Just as valid as a hypothesis perhaps, but not as a theory.
A theory requires some evidence and logical reasoning.
While scientists don't "truly know" in that their knowledge is incomplete; they do have a large body of clues, expirmentation and evidence to help them build a more complete knowledge.
You on the other hand simply have given your hypothesis without bothering to look at any clues further than your own skull, or at least you haven't bothered to publish or explain your clues and reasoning to others i
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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
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I don't know if you are joking, but we certainly knew Mars gravity to within some tiny fraction of a percent. The period and distance of it's orbiting moons can be used to figure it out pretty accurately. You may be thinking of the spaceship that was lost because of metric/english unit confusion?
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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.
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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
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You are certainly right about that. If there is no God then you are no more valuable than a cock roach, because all life climbed out of the primordial ooze. Only a personal God can give personal value.
Bullshit.
Value is given by evaluators. In my case, the evaluators are me, and the people who know me well enough to have a valid opinion of me. I don't need a fancy invisible god to see that human beings are more valuable to human beings than cockroaches.
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The operative phrase there is as we know it. Change the constants a little, and other forms of life are perfectly capable of living. You're giving the fine-tuning argument (http://en.wikipedia.org/wiki/Fine-tuned_universe), which is interesting, but it's a tired canard trotted out by creationists time and a
God built the world for man... (Score:5, Interesting)
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As a physicist you would know that the laws of physics appear to be the same throughout the universe. The binding energies of the carbon atom are just right to make the complex structures necessary for life. There is no other chemistry that we know about that could form any life other than carbon based. Neither scientists nor theologians ever prove anything, but only believe or disbelieve in various facets of their respective discipline.
Of course there's no other chemistry that we know about! Our ability to accurately model complex chemical systems is very limited still, and the vast majority of what we know about chemistry, we know from direct observation of systems in the relatively narrow range of conditions we have here on earth. Maybe in 20 or 30 years we'll have the ability to accurately model the sorts of alternative chemistries that might give rise to different sorts of life, but for the time being, we're limited to what we can
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He did imply his belief by claiming it to be his assertion.
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Re:I may be wrong, Im not an astrologer (Score:5, Interesting)
In much the same way, the molten iron theory is more around currents (fluid currents) causing electrical currents in the core. These electrical currents then cause the magnetism.
Nobody is saying that the iron itself is magnetic (because then it would be magnetite and not iron anyway).
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>Nobody is saying that the iron itself is magnetic (because then it would be magnetite and not iron anyway).
I'm a little confused by this.
There's lots and lots of iron that's magnetic but isn't magnetite. Magnetite and hematite are both iron oxides; magnetite happens to be magnetic, while hematite isn't. (Well, technically, hematite is antiferromagnetic until it's reasonably hot, at which point it's a type of antiferromagnetic that makes it act magnetic, but that's not something you're ever going to no
Re:I may be wrong, Im not an astrologer (Score:5, Informative)
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.
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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 (Score:5, Interesting)
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 (Score:5, Interesting)
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It is a lot simpler on other planets as you often don't have quite as many things crawling around on top of them.
Also they provide other points of reference allowing us to compare our planet with theirs.
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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 (Score:5, Funny)
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.
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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.
Good jape, got a chuckle out of that.
But it's another stolen word, isn't it? Astronomy is the naming of the stars, Astrology should rightfully be the logical study of the stars, along the lines of the word "Geology". Or it could have gone the other way, I suppose, and I'd have "Planetary Geonomy" on my bookshelf.
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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 (Score:4, Informative)
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 (Score:5, Informative)
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.
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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.
One piece of logic disrupts the idea that Mercury would have a solid core... It's proximity to the sun gives it a surface temperature hot enough to melt some metals. Granted, the opposite side of Mercury is also the coldest place in the Solar System (due to the planet's lack of atmosphere and equal lack of rotation.) This could, conceivably imply a solid core. However, just like boiling water, if you heat one side and leave the other side cold, you create a thermodynamic flow which could generate a magnetic
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Yes. Fortunately, as usual, the summary has /nothing to do/ with the /actual/ article that it's referencing.
Uh, right. (Score:4, Insightful)
Re:Uh, right. (Score:5, Insightful)
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. (Score:5, Informative)
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.)
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True, true, and I admit I was also misled by the misleading, inflammitory summary. Such is Slashdot these days, I suppose.
Joke or not,,, I was trying to think of other mean (Score:3, Insightful)
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??
Because someone has to respond to trolls (Score:5, Insightful)
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.
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That's not consensus among climate scientists; that's consensus among feminists.
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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. (Score:4, Funny)
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.
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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."
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[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. (Score:4, Insightful)
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.
But there is a molten outer core.. (Score:3, Informative)
We have proven the existence of a molten outer core inside the Earth, and the proof doesn't depend on the magnetic field, but rather, seismology. Sound and vibration can travel in any substance as a pressure wave - material compressing and decompressing (P-waves). In solids, vibration can also be orthogonal to the direction of propagation (S-waves). Think of vibration in a string, or in a tuning fork. It is known empirically that S-waves travel through the Earth only to certain depth. Because they can't pro
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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 explan
New possibilities in terraforming? (Score:3, Insightful)
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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.
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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 (Score:5, Informative)
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.
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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 does
Re:Summary wrong: Oceans only small variations (Score:5, Insightful)
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.
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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.
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Well we DO know that there is liquid iron and rock in the Earth's interior. Volcanos spew the stuff out all the time.
Now we also know from evidence that the deeper you go, the hotter it gets, miners have encountered this quite a lot.
Now we also know that hot things tend to melt and with our other evidence we have presence of molten minerals(with quite a large amount of iron in many cases) coming up from deeper in the earth than we can study, as well as a lot of evidence that the heat is spread over the ent
Headline is a Lie (Score:2)
Read above.
Ocean currents are /NOT/ being proposed as a cause of the magnetic field.
The headline is a lie.
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I find this much more believable than the swill in the slashdot summary.
Take a look at who submitted it. PEBKAC.
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I wonder when we'll stop being modded as Troll or Flamebait for pointing this out; this is the 10th or 11th bad summary I've seen submitted by you-know-who in as many days. I've been here for 10 years, and said editor is REALLY pretty bad.
Notice that the quote from the paper sums things up rather clearly - it's the editorial *addition*.
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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
Simply solved (Score:2)
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?
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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...
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Better example: Mercury.
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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.
Just last night... (Score:5, Interesting)
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.
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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
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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.
The last I've heard on that very subject was from a NOVA documentary called Magnetic Storm, which aired in November 2003.
In that documentary, they were just preparing for the experiment with the molten sodium, but did not start.
Which sounds like about the same state you have last heard about as well.
I would have hoped in 6 years time they would have been able to start their experiment but I can not find any updates on their work.
I too would be curious to know what resulted from it.
In case you are interested
It doesn't say ocean currents cause the field (Score:5, Informative)
Testing, testing... (Score:2)
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.
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Except NASA has just published data which suggest that the Solar cycle strongly influences the Earth's climate, more so than AGW. So go back to being irrelevant, Al Gore.
A big fish story is circulating into a vortex (Score:2)
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 vo
Pseudoscientists attend! (Score:4, Interesting)
Re:Pseudoscientists attend! (Score:5, Interesting)
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Look at how roundly and thoroughly Alfred Wegener was attacked when he first proposed plate tectonics
I can't comment on Wegener's personal story, although I may see about tracking down a biography. Plate tectonics, however, is a perfect example of an extreme (but true) scientific inference that required extreme evidence, ie., evidence the gathering of which required not only submarines but sensitive magnetometers unavailable to Wegener: http://pubs.usgs.gov/gip/dynamic/developing.html [usgs.gov].
Somehow the creatio
Winds (Score:4, Funny)
Language matters (Score:2, Interesting)
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
Didn't this guy prove it was the molten inards? (Score:2)
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.
No - ocean modulates field, doesn't cause it. (Score:2)
Ocean mass vs outer core mass (Score:2)
I'm highly skeptical of this idea for one reason. The volume of the oceans is MINISCULE compared to the volume of the outer core. In order for the oceans to generate the kind of magnetic field the Earth has, they would need to be highly magnetic. Steel ships orient themselves to the currents automatically type levels. The Earth we see is a wafer-thin skin on the massive iron/nickel mass that is the Earth
How much water is in the mantle? (Score:2)
I guess the question here, is how much water is in the mantle? It seems like volcanic plumes from pretty deep within the earth's crust and below have -steam- pressure in them. One has to wonder if the earth is rather like a giant sponge...a big chunk of rock, yep, but saturated with water.
Re:But this would mean?!?!?!?!? (Score:5, Insightful)
Actually, negative (Score:2)
FWIW, Mars used to have water and may have at one point had a stronger magnetic field than the Earth
Actually, somebody published a paper this week that suggested that Earth's magnetic field might actually accelerate our loss of atmosphere relative to Mars. In fact, Earth right now is leaking atmosphere faster than Mars is, pound for pound. The ionosphere follows the magnetic field lines high up into space, and then the sun just whisks it away.
If this paper and the OP paper stack up, I'd say a good chunk o
Comment removed (Score:4, Insightful)
Re: (Score:3, Interesting)
Mars also has much lower gravity; basically what determines loss of volatiles is if the radiation impacting on the top of the atmosphere can give the molecules escape velocity. The actual mechanism is a bit more complicated than that, but is ultimately bound by conservation of energy.
Mars also didn't lose all its atmosphere to space - some froze as dry ice.
Re:But this would mean?!?!?!?!? (Score:4, Informative)
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.
Re:But this would mean?!?!?!?!? (Score:5, Insightful)
Of course water responds to solar radiation - that's how we get clouds! :-)
Re:But this would mean?!?!?!?!? (Score:4, Funny)
What was it before?
A coffee coaster.
Re: (Score:2, Informative)
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.