This is one of those science stories that is on one hand fairly simple, and on the other hand fairly complex, where the interface between simplicity and complexity causes little balls of misunderstanding to come flying out of the mix like pieces of raw pizza dough if the guy making the pizza was the Tasmanian Devil from the cartoons.
What is true: A scientist named Ryskin proposes that decadal or century scale minor wiggling in the measured Earth's magnetic field is influenced by changes in ocean currents. Plausible. Interesting. Could explain some things. Not earthshaking.
What is not true: The earth's magnetic field is caused by ocean currents. The earth's magnetic field's long term variations, like reversals in field orientation, are caused by ocean current changes. The Earth's magnetic field causes oceanic current changes or the currents are the sole cause of secular variation. The cause of the earth's magnetic field is not, as previously thought, the molten dynamo thingie inside the earth.
Let me explain.
The Earth has a polarized magnetic field, with one pole (which we call "North") located .... up north ... between Canada and Russia, and another pole (which we call "South") located down south in Antarctica. The magnetic field is caused by something.
Every now and then, over long term historical time at scales of hundreds of thousands of years or more, the orientation of the Earth's magnetic field reverses. That reversal may or may not be related to the present article, but if it is, the relationship is not proposed by the author or anyone else. So let's forget about reversals.
Over shorter time scales, there is this phenomenon called "secular variation." The word "secular" comes from the same root as the French "siecle" (century, or age or period) and refers to "short term" variation. Centuries are short from the perspective of geologists.
How thick is a layer of sand laid down by the spring floods each year in a delta? How thick is the layer of mud laid down between winter die offs in a cold deep Pleistocene lake? How far does an active fault creep each year over the three or four thousand years during which it moves?
Who cares? We add up all those numbers and average them out, or we don't even measure them; We simply take the large scale phenomenon (like meters of mud or sand) and that tells us what we really want to know about the geological phenomena under study. Right? Oh, what's this you say? You are actually interested in the small scale variation for some reason? Well, then, you are studying secular variation.
Archaeologists are interested in secular variation in magnetic fields because, if you know within a couple of hundred thousand years or less what a site dates to, and you have a few or more geomagnetic samples from the layers in which your site exists, you can guess where in time the site dates to by examining the exact orientation -- not just 'reversed' and 'unreversed'1 state -- of the magnetic field.
Geomagnetic scientists believe that the earth's magnetic field is caused by a dynamo that functions in the earth's core, a dynamo consisting of one or more giant masses of iron spinning (as is the whole earth) around. Changes in the earth's magnetic field, including both secular variation and reversals, have typically been explained in relation to this dynamo. However, it is true that these explanations have been weaker than one would like, and it is true that over the last several centuries of consideration of this matter, no explanation for secular variation has ever stuck as well as one might like.
So, it has previously been assumed that secular variation in the magnetic field, which constitutes a trend of a westward drift of the orientation of the poles, is caused by details of this dynamo, but this idea has not been nailed down. Also, as mentioned by the author, some of our key ideas about how this dynamo works depend on the assumption that secular variation is caused by stuff happening with the dynamo (or its subterranean context) itself.
The new paper, by Ryskin, takes a slightly approach, comes up with an interesting model which may be plausible, demonstrates empirically that there may be something new to the model, then somewhat overstates it's significance in a way clearly designed to annoy most geomag experts. So yes, a study on perturbation in the Earth's magnetic field is sure to perturb, academically.
Here is the theory in the author's own words, excerpted from the abstract, introduction, and conclusions. (Believe me, you don't want to see most of the middle of this paper. Unless you like watching them make sausage.):
...I propose a different mechanism of secular variation: ...the magnetic field induced by the ocean as it flows through the Earth's main field ... The predicted secular variation [based on my model] is in rough agreement with that observed. Additional support is provided by the striking ... correlation ... between the intensity of the North Atlantic oceanic circulation and the rate of secular variation in Western Europe; this explains... the recently discovered correlation between secular variation and climate. Spatial correlation between ocean currents and secular variation is also strong.
Owing to secular variation, the International Geomagnetic Reference Field (IGRF) must be revised every 5 years ... Since secular variation is believed to originate in the Earth's core... theoretical studies of secular variation have been limited to solving the inverse problem: find the flow at the core-mantle boundary that would produce the observed secular variation ... The results of these studies cannot be compared with observations: seismic data indicate that the Earth's outer core is fluid, but flow in the core cannot be measured or observed.
I propose a different mechanism of secular variation: ocean water being a conductor of electricity, the magnetic field induced by the ocean as it flows through the Earth's main field may ... manifest itself globally as secular variation.
... The ocean-induced magnetic field certainly exists, and may depend on time, including, possibly, on annual and longer timescales. ... The crucial question is whether the ocean-induced field may vary on secular variation timescales. The bulk of [this paper] deals with this issue. Fortunately, one is on a firm ground here: the analysis is based on magnetohydrodynamics. The difficulties, though considerable, are largely mathematical; no hypotheses need to be invoked or introduced. The answer is in the affirmative
...the only remaining question is whether the ocean-induced secular variation is a part or the whole of the observed secular variation. ... while the comparison [presented here] does suggest that secular variation in its entirety is induced by the ocean flow, this by no means constitutes a proof of the proposal. In fact, a definitive proof may never be possible, but as the accuracy and completeness of the data continue to improve, and further computations are carried out, sufficient clarity on this issue should be achieved ...
The results presented suggest that the observed secular variation of the Earth's magnetic field owes its origin to the ocean flow. ... Data analysis exhibits striking temporal correlation between the intensity of the North Atlantic oceanic circulation and secular variation in Western Europe...
There is little doubt that these conclusions will be met with skepticism. And so they should: the results presented by no means constitute a proof. But the possibility of direct connection between the ocean flow and the secular variation of the geomagnetic field is bound to stimulate further research, especially in view of the implications for the question of the origin of the main field.
The current consensus is that the main field is generated by the hydromagnetic dynamo in the Earth's fluid outer core. Secular variation has been taken as evidence of motion in the core since the time of Halley (1692). Halley thought that secular variation, the westward drift in particular, was caused by differential rotation of a magnetized solid core, separated from the `external parts of the Globe' (also magnetized) by a `fluid medium'. Contemporary theoretical studies use the westward drift to estimate the characteristic large-scale velocity in the outer core, and to conclude that dynamo action is possible. 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.
With respect to the relationship between climate variation and magnetic variation, the author offers a weak but intriguing empirical data set. Have a look at this graph:
Figure 1. Does ocean flow cause the geomagnetic jerks? Comparison of oceanographic and geomagnetic data shows that the trend in secular variation is closely correlated with the trend in the ocean-flow intensity. Points--the oceanic transport index, a measure of intensity of the North Atlantic gyre circulation (Curry and McCartney 2001; data absent in some years, especially between 1979 and 1984). Lines--secular variation of the geomagnetic field (differences between successive annual means, east component) at three observatories in Western Europe: solid line--Eskdalemuir, dotted line--Niemegk, dashed line--Chambon la Foret (World Data Centre for Geomagnetism 2007). It is seen that the hitherto unexplained geomagnetic jerks of 1969, 1978, 1991 and 1998 (De Michelis and Tozzi 2005) are correlated with sharp changes in the trend of the ocean-flow intensity. See section 8 for details.
The dots are the climate data, and the squiggles are magnetic variations. We are not impressed. But we also cannot reject this out of hand. What is interesting here is this: Every few years, almost like clockwork, somebody comes up with a correlation between either sunspots and climate change or magnetic variations and climate change. The fact that these two attempts at explanation come up all the time may be little more relevant than as an argument that untrained people should not be let near real data and statistical analysis tools. But it could also be that there are vague enough links among these phenomena that they will continue to peek out from the data, and failure to confirm or replicate preliminary conclusions is due to a lack of proper causal paradigm than anything else. The present paper asserts that the climate change causes the magnetic change, which is the REVERSE of all prior work of which I'm aware. (Here, "climate change" = oceanic circulation.) Having the causal arrows backwards or otherwise mixed up can certainly slow down research.
The other major conclusion, referred to in the extended quote above, is that since the dynamo model is based in part on the old and now in question secular variation model, geomag experts have to go back to square one, or at least, square two or three, and rethink what they've got.
At the beginning of this post, I noted that there was a certain amount of 'getting it all wrong' out there. The author's final statement about our need to rethink the dynamo has certainly contributed to this, but inappropriately so. This paper does not suggest that the dynamo is not there or that the dynamo does not create the Earth's magnetic field.
Nonetheless, the summary overview from the same journal in which the paper is published makes this statement:
400 years of discussion and we're still not sure what creates the Earth's magnetic field, and thus the magnetosphere, despite the importance of the latter as the only buffer between us and deadly solar wind of charged particles (made up of electrons and protons). New research raises question marks about the forces behind the magnetic field and the structure of Earth itself.
source
This statement has all the hallmarks of a typical bad press release: Alarmism, fear, hints that everything we know is wrong, and the suggestion of an impending paradigm shift.
This may be in part what lead the contributor on Slash Dot who tagged this story to totally screw the pooch, in cooperation with the Slash Dot editors:
Ocean Currents Proposed As Cause of Magnetic Field
...a recently published paper proposing that ocean currents could account for Earth's magnetic field. ......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."...
Uffda. Shame on you Slash Dot.
___
1We call the unreversed state of the magnetic field "normal." Typical chrononormative colonialist scientist jargon.
Ryskin, G. (2009). Secular variation of the Earth's magnetic field: induced by the ocean flow? New Journal of Physics, 11 (6) DOI: 10.1088/1367-2630/11/6/063015
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Again with me inadvertently being a stickler for linguistics, but shouldn't we call this a hypothesis?
I mean, I'm all for accepting that the ocean currents can provide a magnetic field, but one would think the dynamo theory isn't going to get knocked out and replaced by ocean currents causing variations in the magnetic field. Calling this a theory is like calling creationism a theory (as compared to evolution, say).
Perhaps a little too harsh to compare this with creationism, Jason Thibeault. Creationism doesn't even rank anywhere near 'hypothesis'. It's somewhere below 'talking out of your arse' and a little above 'drooling incomprehensibly', IMHO.
Oh, no worries, agreed that it's way too harsh, it was illustrative more than anything. I'm just throwing that out there because my experience with arguing with creationists generally leads smoothly into an argument that "evolution's JUST A THEORY", when they're using the layperson's meaning of theory, meaning hypothesis. Theory / hypothesis is one of those few semantics arguments where it's really important people understand the quantifiable difference.
This is a theory or a model that comes along with a bunch of hypotheses. A hypothesis (to use the term very correctly) requires a falsifiable prediction. Nothing I talk about in the post above is really a falsifiable prediction. The body of the paper itself is an alternative mathematical model (which I studiously avoided in this discussion).
So think of this as a model that if correct would be a theory or part of the larger theory of the planetary magnetic field.
Gotcha. So I definitely wasn't being fair about it, my idea of "theory" was too narrow. Again, probably comes from fighting with religious folks.
I'm interested in this mostly because we already have a pretty good base in the dynamo theory, so how much is going to end up being thrown out? I bet the oceans really do have an effect, and I bet it's significant, so it would be nice to see how much is ocean and how much is the Earth's core. That's the brilliant thing about science, the fact that new info leads to new insights.
Admittedly I didn't read the paper nor have time to read it at this point. BUT:
I found that graph somewhat interesting. Given that the Earth's field ranges from 30,000 nT to 60,000 nT at the surface, this is a variation on the order of 0.01 or 0.0001% !! Given that magnetometers at the surface routinely measure differences on the order of 100's on nT in a few hours, I'm curious to understand how (a) the 50 nT/yr change was made (an average of something??), and (b) what are the error bars on that calculation?
Further to that, in the description of the graph, he notes "jerks" in the graph at 1969, 1978, 1991 and 1998. Given that the solar cycle maximum have been 2001, 1990, 1979, 1968 (approx.) and that strong changes in the magnetosphere are directly related to the strength of the solar wind and interplanetary magnetic field, it seems to me that these "jerks" are not necessarily well explained by his theory. The solar wind/IMF would correlate to changes in the ground magnetometers (this is how we monitor waves, substorms, etc generated in the magnetosphere or heliosphere). Therefore, if the solar wind and IMF are stronger - the change in the magnetometer would be larger. So - did he remove these effects from his plot?
Also, the points do not correlate well at all times. How is this explained (especially around 1980-1983)?
Seems a bit suspicious to me.
The first part (about having the same roots) is quite obviously wrong, isn't it?
(http://www.etymonline.com agrees with me)
Pete,
Your source is incorrect. Or at least, dome guy named Doug who has a web site quite obviously does not trump the OED.
"In scientific use, of processes of change: Having a period of enormous length; continuing through long ages. a. Astr. Chiefly of changes in the orbits or the periods of revolution of the planets, as in secular acceleration, equation, inequality, variation. The terms secular acceleration, secular variation were formerly also used (with reference to the sense âcenturyâ of L. sæculum) for the amount of change per 100 years; similarly secular precession "
The OED does not state, as you do, that the two words come from the same root.
Even if one gloss of Latin "saeculum" was "a 100-year period" i.e. a century, that does not mean the two words "century" and "secular" have the same root. The word "secular" has a different source in Proto-Indo-European than "century" does. "Century" clearly comes from *kent-, ie., the number one hundred, whereas Latin "saeculum" does not derive from this root.
I'm referring to the latin, which is older than Old French. Therefore, older.
Even asking the question of the meaning "century" in Proto-Indo-European is really really funny. What was their word for Space Shuttle?
Huh? No one is "asking the question of the meaning 'century'".
Again: The word "secular" does not have the same root as the word "century". I, Doug, and the OED all agree on this. Perhaps you are unclear on what it means to share a root - it doesn't mean to have a similar meaning. It means to derive etymologically from the same root word. Example: the English words wit, wisdom, and witness, the Latin videre (to see), the Sanskrit "veda", all share a root.
Your post was a brilliant takedown though, and I shouldn't have nitpicked one tiny mistake...
Grr. Thanks Greg. Unfortunately plenty of "damage" is already done and people will re-spew this filth.
Pete: Right, what was I thinking. My brain was working in French and I was writing in English. Century has a totally different root than Siecle, which shares with secular the old French root seculer (also shared with modern French seculier) (pardon the lack of accents). Century is Latin centuria, of course.
So just take the above and pretend it is in French and we're all set.
GDB: This is sufficiently obscure that maybe we've headed it off at the pass.
Hey, I get all my news from Greg Laden's.
(And I get my tendency to spout off all my ridiculous preconceptions from my mom.)
Am I just misunderstanding something or is there an errorish thing or lack of clarity or whatever you want to call it here:
My impression was that the pole of Earth's magnetic field which is currently nearest the geographic north pole is actually a magnetic south pole, as it attracts the north pole of a bar magnet.
Anne:
Nope. Good call, though, in that the concept is essentially correct. The magnetic pole, up in Canada, is called the North Pole because it is the pole that is up North. It could have been called the Harvey Pole if the ancients called that direction Harvey, or we could rename it "A" and have the other poll be "B" or whatever.
But the historical terminology is as follows: The Magnetic "Pole" (the place where the magnetic flux lines go vertical into the earth) that is in Canada (at the present moment) is the North Pole.
The end of your compass needle is actually called the "North Seeking Pole" which we shorten to "North Pole."
Looking at the Wikipedia article I link below I think I see why I misunderstood your terminology. They seem to use an implicit distinction between the "North Magnetic Pole" as a proper noun (referring to the pole which is nearer geographic north) and a "magnetic field north pole" as a general noun (an example of which would be the pole nearer geographic south). I tend to come at this from a physics perspective, and I think it's pretty common in physics to just treat "north pole" as an abstract term for the end of the magnet the field lines come out of (which is in turn is the result of arbitrary sign conventions for the charge of the electron and the magnetic force equations), and to drop "-seeking" as unnecessarily Earth-centric.
So, roughly, it seems to me that I was saying, "Geographic North is magnetic south," while you were saying, "Geographic North is Magnetic North," and I didn't catch the importance of your capital letter.
http://en.wikipedia.org/wiki/North_Magnetic_Pole
Geographic North is the North Magnetic Pole from which the hypothetical flying flux lines come (they go to the SouthPole, which is the South Magnetic Pole).
North = North, South = South
These are capital letters because they are geographical locations.
The compass needle that points to the North Pole is called the North Seeking Pole of the compass, which is shortened to North Pole of the compass, which is correct only if you know that it has been shortened. Otherwise, as you point out, it is incorrect.
Most of this terminology is made up of conventions established well before the processes were understood at even a basic level. This is true in all of the sciences to one degree or another.
I don't think we actually disagree. I just think the speech convention I'm used to from abstract physics is slightly different from the more concrete convention you were employing, which is why I didn't initially understand your statement. Anyway, it's a very trivial point of course and I am sorry to have wasted your time with it.
secular, cyclical, wheel, revolve all same PIE source I'd guess.
Ocean currents are directed by tectonic plate movements which I think are caused by relative speeding/slowing of the earth's rotation. I've written about it under 'pinwheeling pangea'.
The folks at the IOP press office have must have learned how to hyperventilate without air...
From the man who first set down the theory of the Solar Wind:
"On Earth's surface we are well protected by the massive atmosphere above us. This thick blanket of gas diminishes the cosmic rays so effectively that the radiation dose over a lifetime is of no consequence." (Eugene Parker, http://adsabs.harvard.edu/abs/2005SpWea...308004P)
The magnetic field accounts for maybe 10% of the reduction in cosmic rays. The atmosphere is the important barrier (else we'd all die from cosmic radiation if we went to high latitude where, though the field is stronger, it is oriented in such a way that solar and cosmic radiation have ready access). The solar wind, being far less energetic than cosmic rays (many orders of magnitude), would not penetrate the atmosphere. To be charitable, sometimes the Sun spews out energetic particles that are dubbed "solar cosmic rays", and sometimes these reach the ground (a so-called Ground Level Event, a few times every decade), but that's not the solar wind, and it certainly doesn't kill us.
High altitude flyers and low earth orbit astronauts wear dosimeters because they are above most of the atmosphere--the magnetic field at the space station is still about 80-85% as strong as that at the surface of the Earth immediately below the station, whereas the atmosphere is down many orders of magnitude.
"The only buffer" indeed. Alarmist and wrong. Shame on the IOP.
Anne, you're correct about the poles. The North Pole is actually a magnetic south pole because the field lines point into the earth.
"The only buffer" indeed. Alarmist and wrong. Shame on the IOP.
Shame on you Paul for expecting anyone to believe that what you say is closer to the truth than what the IOP says. I'm not making an argument either way- I came here to try to learn about this and any other subjects that pertain to magnetic fields. I actually would gravitate toward what you are saying simply because I tend to be a bit cynical when it comes to the inevitable tendency of seemingly every group in existance to make us all fear for our lives at the mere introduction of any subject. I have gotten to the point where I rarely believe anything at all because all the evidence is spun and re-spun depending on what the messenger needs for us to believe. When the poles reverse the Earth will crumble and we will all burn or drown or get blown away or get frozen. In 2000 years there will be no magnetic field to speak of, and all earthlings will fry on the spot. Wow- maybe I shouldn't have had kids. Poor things- what's that? Maybe not? Maybe the poles shift more regularly and nothing happens at all? Maybe the magnetic field has little significance at all when it comes to our protection? Oh- the poles shifted last week and once in April as well? Scientists are funny. Phoney scientists are even funnier. All anyone ever says is I don't really know shit. I don't really know shit. The laws of physics state that this and that and this and that- don't worry about the fact that most of those laws are affected by God knows how many phenomena that can't be explained by scientists. Don't worry about dark matter and the other 96% or whatever it is. Blah blah blah. Admit you know nothing and shut the fuck up.
G'day all,
Not a geomag expert, just asking for info. If the formal definition of a magnetic pole is where a magnetic compass, on a horizontal axis, would point straight down, do we not now, as per the World Magnetic Model, 2005, vertical secular variation, now have two north magnetic poles? With the new one in Siberia, half way between Lake Baikal and the Arctic Ocean, being by a whisker the stronger, and hence now the formal magnetic north pole? Have I got this all wrong? And if not, has no-one noticed? Or, where has it been published?
I put some of this up on ABC Pool, as below
http://www.pool.org.au/image/peter_ravenscroft/the_vertical_field_defin…
See also the adjacent posts there.
Would appreciate expert opinion.
Regards,
Peter Ravenscroft
Geologist, Closeburn, Queensland.
PS: Am of the opinion that the coincidences in the graph at the head of this post are not trivial, being one of the regular-as-clockwork-mice who do think that a whole series of maps from the real world show that deep geomagnetic changes are far more powerful fiddlers with climates than CO2 or the solar or cosmic magnetic fields. Geomag field reversals appear to wipe out the Antarctic icecap, see the oldest ice anyone can find in the deep bores at Dome C and Dome F. Where is all the Early Pleistocene ice? Something put a blowtorch to the icecap, just at the last reversal, looks like. I think the holy grail of drilling pre-million year ice may not be achieved.
I'm new to this site but not entirely new to the internet. My internet site is titled creationtheory.com but don't jump to hasty conclusions. I thank Mr Laden for his timely, entertaining, and broad-minded presentation of this paper. I am a geologist but not a geophysicist. Maths is my nightmare rather than my sweet-dream dream topic.
I note Mr Ravenscroft's contibution above with mild interest. I would value any opinions forthcoming on his query.
The terrestrial magnetic field puzzled Einstein. ANU Prof. Stuart Ross Taylor (science investigator for APOLLO) writes to the effect that our understanding of terrestrial magnetism hasn't really advanced much since William Gilbert back in the latter part of the 16th Century. I hypothesize it can be explained as a combination of conventional dynamo(s) in conjunction with novel states of matter induced by extreme pressure, triggering areas of something perhaps akin to superconduction. However, our entire field could not be the product of a superconductor dynamo on the scale of the currently proposed conventional dynamo, because such a dynamo would produce a much stronger field than that currently observed.
What really interests me in this paper of Ryskin's which you have rendered intelligible to maths neuts such as myself, is the proposal of a link between ocean circulation and magnetism. We know that oxygen is an exceptional element with unusually strong magnetic properties. We know, along with Mr. Ravenscroft, that despite all the politically correct obfuscation and outright denial, the eath's climate has been moderated at least since the beginning of the Palaeozoic so as to allow the existence of complex life. We know that to do this by regulation of greenhouse gas levels alone is a joke.
Question, to all geophysicists, physicists, and calculator drivers in general: a) Is the atmosphere or parts thereof a magnetic fluid, susceptible to mechanical action by magnetic force? Does the ocean fall into the same category? Is it conceivable that the temperature and/or the composition of the atmosphere and oceans can affect in any way magnetic force lines? Keep in mind, we are in the Quantum Age.
You will grasp my purpose. The sun and the earth interact to ameliorate and guide our climate. It's got to be two-way. It's far more sensitive than volcanoes belching CO2 or dry-ice comets periodically crashing. There has to be some sort of 'information' interaction, and it involves the solar and terrestrial magnetic fields nearly for certain. What do we have by way of possibles?
A simpler and yet more scientific rigorous answer (it is consistent with *all* observations unlike the ocean current theory)to the question of what generates the earths magnetic field can be found at the above url. Basically it is generated by the difference in rotational speeds between the earths solid core and the outer mantle. We already kniow the core rotates faster in one direction. And that seismic waves indicate it is elongated in the n-s axis.
Jay: The paper in question does not obviate that explanation. It raises questions that your explanation, maybe because it is simpler, seems to skip, though.
What is proposed as the cause behind a planet's core being 'elongated ... N-S', and what could cause it to change to bulge the other way, which I take to be the plane of the equator?
(Intuitively, I think of it as bulging in the plane of the equator, as the Earth in toto bulges.)
Bulgings and counter bulgings -- any known mechanisms?
The above theory, I think, is closer to being correct than the prevailing standard dynamo model.
I think the general idea is a good one. There are many reasons why I don't like the Earth core dynamo theory. The primary reason has to do with our observations concerning planetary magnetism in general. The biggest magnetic field is Jupiter then Saturn; Neptune and Uranus have unusual magnetic fields and do not seem to conform to the core based theory of planetary magnetism. Instead I ascribe to the atmospheric interactions as the primary cause/ source.
On Jupiter the atmosphere and core are rapidly spinning. The layers of atmosphere interact with each other causing ionization of gases and probably continuous electrical currents within the atmosphere as well as probable continuous lightening. These electrical currents would accordingly flow in the same direction as the "air currents." This theory also better explains the magnetic fields of Neptune, Uranus and Mars. Mercury is close to the sun so the solar wind of about a million miles per hour would accordingly be the cause of its magnetic field.
Translating this to the Earth it would be the interactions between the ionized atmosphere, the land and the sea rather than the molten core. The sea would have electrical currents that would coincide with the spin of the Earth which causes the prevailing winds. The largest solar storms in time accordingly would reverse the Earth's magnetic fields based upon which pole large solar wind "clouds" would interact with.
that was awesome huge great!!! any more therios
Earths electromagnetic feild is caused by to positive magnetic forces. 1st, salt has magnetic properties the constant movement of the oceans salt water oceans causes electrostatic energy which acts as a conductor, normally this energy would just be absorbed by the earth but the earths hot core acts as a thermal conductor having it's own magnetic properties, these 2 magnetic forces pushing against each other causes a loop that we identify as earths electromagnentic feild. A space probe recently found that Venus had no electromagnetic feild even though it almost certainly has an iron core, there is no salt water oceans to cause an opposing effect so it could not be detected from space.
"Any intelligent fool can make things bigger, more complex, and more violent. It takes a touch of genius -- and a lot of courage -- to move in the opposite direction."
"Imagination is more important than knowledge."
"Science without religion is lame. Religion without science is blind."
"We can't solve problems by using the same kind of thinking we used when we created them."
"Education is what remains after one has forgotten everything he learned in school."
I'm sure by reading the comments, that all of the participants consider themselves intellectually superior to Mr. Einstein. My suggestion is, listen to those who speak to enlighten, not those who speak to impress.
Trying to baffle with bullshit is so 70's
Not a geomag expert, just asking for info. If the formal definition of a magnetic pole is where a magnetic compass, on a horizontal axis, would point straight down, do we not now, as per the World Magnetic Model, 2005, vertical secular variation, now have two north magnetic poles? With the new one in Siberia, half way between Lake Baikal and the Arctic Ocean, being by a whisker the stronger, and hence now the formal magnetic north pole? Have I got this all wrong? And if not, has no-one noticed? Or, where has it been published?
Not a geomag expert, just asking for info. If the formal definition of a magnetic pole is where a magnetic compass, on a horizontal axis, would point straight down, do we not now, as per the World Magnetic Model, 2005, vertical secular variation, now have two north magnetic poles? According to weathercast forecaster, with the new one in Siberia, half way between Lake Baikal and the Arctic Ocean, being by a whisker the stronger, and hence now the formal magnetic north pole?
This might help answer that question: http://tinyurl.com/4on9z59
Explain the causes of Earth's magnetism on the basis of modern scientific observations? Anyone please
Why not google for it? I do know, at least past the "there needs to be some magnetism there already", but why bother if you can't do the least amount of work yourself?