Theory of earth magnetic field Or, I found for my surprise some days ago, that there was no explanation on how does the earth magnetic field work. I've always thought of it as an evidence and as such I assumed it was allready theorized. I seems clear for me that some facts are proven and those will leed to this theory I'm presenting. Fact number 1 There's a large percentage of iron and other metals inside the earth. Fact number 2 Those metal are also in the planet core. Fact number 3 The planet core has a very high temperature. Fact number 4 The planet core is in liquid state. Fact number 5 Some metals generate magnetism upon friction. Fact number 6 The inertia law. Fact number 7 The liquid and gas behavior upon movement of the earth (currents). Fact number 8 The universal gravitational effect. In presence of this facts one can imagine that the earth is mainly a liquid planet with a relativly small hard shell, wich is mostly covered with water. I am by this classifiyng the magma as a liquid, once that it has a liquid behavior, demonstrated in every volcanic eruption worldwide. Therefore, one can assume that the liquid core of the planet will suffer the same efect verified in the atmosphere and in the oceans. That is, the planet core has inner currents. Those inner currents by their turn generate friction among all the elements in presence, includind the metals. And some of those metals when frictioned generate magnetism. The combination of the trillions of small magnetic fields generated by that friction and the interaction among those will then generate the planet magnetic field. The interaction results from the proximity amoung all those trillions of small magnets, like if one person ghater a group of magnets and reunites them in a small space, the positive side will push away the other positive sides and atract the negative sides, reorganising the magnets positions in a one way orientation. Another way of visualising the effect of the rotating movement generated by a hard shell containing a liquid interior, is by watching a glass of water with some small solid objects inside. As one rotates the glass around its geometrical center one can see that the liquid stays stationary during some time while the glass continues its rotating movement, and even when the liquid is turning its speed is diferent than the glass that contains it. Another effect of this inner currents is that the small magnetic fields are moving, therefore leading to the changes in the earth magnetic field, the magnetic declination (declinação magnética in portuguese). Another of the forces involved in this movements, or currents, is the gravitational effect of the moon. As the gravitic effect of the earth satelite is not restricted to earth's surface it also affects the liquid core. The same principle aplies for the sun's gravitacional effect upon the earth's core. Allthough small, those magnetic fields are in very vast numbers, as we've only scratched the surface of the planet when considering its diameter. In conclusion, this effects of friction delivered by the planet's rotation, the moon and sun gravitational forces, generate a great amount of small magnetic fields wich by their turn act togheter to generate the planet's magnetic field. João Pedro Gonçalves Viegas Jacinto
I'm not a expert on this but this is what I've come to understand about the core: Due to the great pressure the liquid metal in the core is actually solid, and rotates slower (or was it faster) than the rest and therefor gives rise to the magnetic field.
As I understand it, the main unresolved problem is where is the long term driving energy source. Short term (20,000 years or less) a model of the magnohydrodynamis does quite well, showing the "flips" of only a few thousand years duration etc. Read more here: http://www.psc.edu/science/glatzmaier.html and http://science.nasa.gov/science-news/science-at-nasa/2003/29dec_magneticfield/
I doubt we can call the core solid, their may be some solid pieces but that immense heat and twisting pressure liquifies the matter. I would bet that it matters which direction you are standing close to the core as spinning faster or slower. Materials should flow at an enormous pace in the direction of the equator yet be relatively still nearer the axis. Like you can put the core on the tip of your finger and spin it as a basketball. The further away from the axis of your finger the faster speed that point encounters on a trip around the finger. The initial 465.1 m/s(cite) difference from the equatorial edge and the axis of this core basketball facilitates the rotation of the magnetic field. The switch in polarity that occurs every thousand years or so is most likely due to effects of the sun's intense electromagnetic influence. It flips the basketball upside down every now and then. But it does it in a fluid way as to not obstruct the rotation.
I think Cyperium is correct. The core is solid in the sense it rotates as a unit without any internal relative movement. Above that solid core is liquid iron (and some other heavy elements) which does not rotate as a rigid unit but has shear and dissipation associated with it. The rotation of the outer layers, the crust, is being slowed by tide's forces. It is the shear torques that transfer this slowing of rotation to the solid core, but there is a lag. I.e. the angular rotation of the solid core is always very slightly faster than the crust. Highly unlikely as the sun can only effect the Earth's rotation via its gravitational gradient which is quite small as it decrease as the CUBE of the separation.* Also there is no reason to think that the sun has larger short period (a few thousand years) variation of any of its characteristics. If it did we would not be alive. Your link is only explaining why the siderial day differs from the 24 hour day (by one day cumulative each year)**. It also may concerns the nutation effects due to Earth's orbit not being exactly circular. Nutation of the moon (and Earth's size) is why we can see nearly 60% of moon's surface. In my quick skim I did not see the word "nutation." * The magnetic gradient falls off even faster and has essentially no effect on the earth except the ionosphere structure. **If Earth did not rotate, the sun would appear to go around the Earth once each year - that is the one day per year difference.
Always thought it was the convection in the Mantle and/or Outer Core that creates a current which results in a magnetic field.. Sort of the same as an updraft in a thunderstorm creates a current, it just that the thunderstorm discharges in pulses. Well this was what I was taught way back in high school. Dont know the modern theories.
Solid or liquid? Hello Thank you all for your posts, they make the discussion more interesting. As the core of my theory is to launch a serious debate arount it. You all know that it's impossible with current technology to demonstrate in pratical terms any theory of this kind. But a someone also thought that the earth was spherical long before it was demonstrated... I agree with MOOse rather than Cyperium, as I find very hard to imagine a solid core considering the very high temperature of the core: If just a few miles bellow the temperature is so high to melt solid ROCK and metal, how would any material resist that? Only possible if the core was made of a material totaly unknowed, that suports thousands of degrees celcius without melting. I'm not stating it is impossible, but that it is statisticly a very remote possibility. And pressure does not transform liquid to solid, although it may transform carbon to diamond, a liquid under pressure remains liquid. Otherwise the ocean bottom would be gelatinous. And this is the latest theory about this subject: I'm not claiming that previous ones are wrong, but it seems to me that my theory responds to all the doubts in previous ones, has the changing polarity for instance. Another interesting one is: ww.ncbi.nlm.nih.gov/pmc/articles/PMC58687/?tool=pmcentrez (it's www has I can't post links here) Once again thank you for enriching the discussion. Best regards JP Jacinto
Welcome to sciforums. Liquids, by definition do not have atoms /molecules orderly arranged and thus normally have more volume than the solid state (ice being the most notable exception but that is due to it being a polar molecule with the two positively charged Hs on one side, 105 degree angle between them as seen from the negatively charged O--) Below 4 C these polar (++ H2O -- ) units form chains with the O-- of one sort of stuck between the two H+ of the next. These flexible chains, all tangled together, leave more space in the mess so ice is less dense than water but that is a rare exception to the rule solid is more dense. It is the high pressure at the core which forces the more dense solid state, despite the high temperature and despite what you may imagine. Also I think sound waves from earth quakes passing thru the earth have confirmed it is a solid. Speed of sound in solid differing from a liquid. Let this be a lesson to you. Never extend your human experience into a range of conditions very different from where your intuition was formed. Quantum mechanic is a good example of why not. Measure and find the truth. The earth's core is solid. Measurement and theory (outlined above) agree.
JP you have been posting this self indulgent nonsense on other forums. You have been shown quite clearly that your fundametal ideas are wrong, yet you persist in coming back with the same tired, foolish, poorly reasoned, unsubstantiated claptrap. If you are mentally ill please seek counselling. If you are poorly educated, go get a proper education. If you are merely a fruitcake, please dry up and pollute somewhere else. Despite appearances fools are not welcome here. You do not have a theory. You have an idle speculation based upon basic misunderstandings of how the world works. I notice you have omitted from this post the fact that you acquired many of your ideas from a Discovery documentary. So at least you have learned that such a source will not impress anyone who knows something about science. They thought the Earth was spherical precisely because that spehricity could be demonstrated: the shadow of the Earth on the moon during a lunar eclipse is the obvious example. Even the points you make en passant are wrong. Fortunately the physical condition of the core is not limited by your imagination. (That would make it a very small item, indeed.) We can calculate the approximate temperature and pressure of the core. We can estimate its composition from seismic velocities and reasonable propositions concerning planetary formation. On that basis we can predict a largely iron core, the inner part of which is - because of pressure - solid. We can duplicate these temperature and pressure conditions in the laboratory and these confirm the theoretical projections. For example this study. The temperature a few miles below is not sufficient to heat solid rock and metal. If we go several miles below - to specific regions where there are upwelling convection currents of hot solid rock we will encounter partial melting. During partial melting a proportion (typically small) of the rock, consisting of the minerals with a low temperature of formation, will melt. The bulk of the rock remains solid. Real observations made by real scientists of real materials in real conditions in real laboratories consitently demonstrate that you are wrong. See the xample quoted above, or google for a dozen, or a hundred other examples. Pressure does transform liquids to solids. This is establishes for a wide variety of materials. Pick up any book on Materials Science, or Metallurgy and you will find countless examples. Repeating this foolish statement merely makes you look like an ignorant peasant. If you genuinely wish to learn I shall be happy to locate a reasonable primer on the subject that will help improve your understanding. Unfortunately I fear you are a close minded cretin who would rather believe what you want to believe than to learn what is real. The established view, validated by some very good computer modelling, is that convection currents in the outer core initiate a self-exciting dynamo, responsible for the magnetic field. There are many fascinating details to be ironed out (pun intended), but the broad theory seems sound. Recent identification of a light element enriched outer zone in the liquid core is an example of such detail. The light elements may be being expelled from the inner core as it progressively enlarges. Movement of these light elements upwards may help maintain the convection currents within the outer core.
A University of California, Berkeley, geophysicist has made the first-ever measurement of the strength of the magnetic field inside Earth's core, 1,800 miles underground. The magnetic field strength is 25 Gauss, or 50 times stronger than the magnetic field at the surface that makes compass needles align north-south. Though this number is in the middle of the range geophysicists predict, it puts constraints on the identity of the heat sources in the core that keep the internal dynamo running to maintain this magnetic field. medicaldaily.com/news/20101217/4716/first-measurement-of-magnetic-field-in-earths-core.htm
Welcome to sciforums F-X and thanks for the interesting link (which lacks the www. in front) There, among other things, I read: "...About 60 percent of the power generated inside the earth likely comes from the exclusion of light elements from the solid inner core as it freezes and grows, he said. ..." That part I made bold, is called "zone refining" when man repeatedly does it to a moving liquid section of an other wise solid rod get very pure silicon for solid state devices. More confirmation that nature has done nearly everything, including running a fission reactor on Earth, before man does it.
I can't post real links until I have posted a certain number of times (no doubt to discourage spammers and spambots). So I chopped off the www to fool the software. But it got me posting at least. I've always wondered about what causes the planets magnetic fields as well.
magnetic planetary field. Hello. Welcome to this discussion F-X. Ophiolite, I have ignored your slow minded remarks on other forums and will continue to ignore your jerk remarks here, has no knoledge comes from discussing with stupid persons like you. This is my last response to your coments and offences. Billy T, I acknowledge that you have a scientific mind, when you say that you think, rather than your sure. That's the spirit for a honest discussion. Has people that think they know everything are the biggest ignorants. Not your case certainly and for that attitude I thank you. I feel reasonably confortable in english, but please keep in mind that it´s not my mother language. Back to F-X link, I was pleased to read that Bruce A. Buffett, professor of earth and planetary science at UC Berkeley also considered that the moon has some effect on the magnetic field. I end with a sentence I found years ago: When all think the same thing, no one thinks a great thing. Thanks for the honest contributions, please carry on. JP
You have ignored my slow minded remarks because they have highlighted the fact that your 'theory' is wrong. It is demonstrably wrong. You can ignore me all you wish - I expected it. It will not alter the fact that you are wrong, or that you lack the imagination to recognise this. Fortunately, other readers will understand how wrong you are. That is my intention. You have made the mistake, a common one, of thinking that different is equivalent to better. You have compounded this by setting the standards by which a theory is to be judged exceptionally high for current thinking, and incredibly low for your own ideas. Please Register or Log in to view the hidden image! If you had an ounce of integrity you would address at least one objection. I'll give you a chance to act honourably: justify your claim that the innermost part of the Earth cannot be solid because of the high temperature. To do this you will have to offer laboratory data that contradicts a host of observations that show high pressure can counteract high temperature and render some materials solid. You will also have to provide citations that contradict the seismic interpretations that indicate a solid inner core. If you cannot do that then you must, if you are an honest man, admit that the inner core of the Earth is probably solid. Are you an honest man?
You are too generous to even say: 'theory.' - he admitted he only imagined that it was liquid (based on his experience , I assumed). I explained why almost all solids are more dense than the same temperature liquid (and why ice is an exception) in post 9. Told explicitly that the extreme pressure forced the core to be in the more dense state. Mentioned the confirming earthquake sound waves, etc. I also suggested that he lean for his error not to apply human experience outside of the range it is known to be valid and mentioned that quantum mechanics is a good example of why not. Like you I don't consider my efforts to educate him a total failure - although he does not learn, other readers probably did.
In my original post I said this: "You do not have a theory. You have an idle speculation based upon basic misunderstandings of how the world works." This is my eternal hope. And occassionaly the object of my education/attack/derision turns around and says thank you. But I don't hold my breath: anoxia is dangerous.
Hello I found that there is one kind of person that follows this forums... the kind uncapable of having is own idea or theory, and therefore gets off by criticising others that reveal creative thinking. (a litle bit like the movies critics... that everyone konws are frustrated actors or directors). The reason why I posted the theory in several fórums is to reach some real scientists, not only opinion makers (profissional or not). Hopefully, one day one scientist will stumble upon my theory and develop it to the next level... I don't have the means to carry on a demonstration of my theory, nor does any HONEST man or woman in present times, has the technology to demonstrate it wright or wrong simply does not exist yet. In the future, near or far, man will know how earth is beneath the knowned shell, and the magnetic fiel will be fully understand. I made the part I had to do. Are you honest too? Billy T...as a moderator...?? you also faill. Are you upgrading to instigator? Did youo not see the offensive terms that ofiojerk used in the first reply to this post? Is that your level of education or are you above that very low level? I wont be going in a useless discussion about the solid or liquid state, but I just have to say this: -A solid object maintains its form in the absense of pressure and external influences. If you had water inside the earth core would it be solid? What would happen if the pressure was removed? would the water still be solid? Think about it Billy T before you post from your altar... and goodbye.
For the record JP, I note that you have failed completely to address a single one of the observations I have provided. These observations are verifiable and repeatable. They are scientifically sound. They demonstrate that your understanding of the subject is erroneous. Address those observations; explain how they are in error; explain how your 'theory' offers a better explanation. Or, spout banal, emotional claptrap. and good riddance.
The Earth's magnetic field is similar to that of a bar magnet tilted 11 degrees from the spin axis of the Earth. The problem with that picture is that the Curie temperature of iron is about 770 C . The Earth's core is hotter than that and therefore not magnetic. So how did the Earth get its magnetic field? Magnetic fields surround electric currents, so we surmise that circulating electic currents in the Earth's molten metalic core are the origin of the magnetic field. A current loop gives a field similar to that of the earth. The magnetic field magnitude measured at the surface of the Earth is about half a Gauss and dips toward the Earth in the northern hemisphere. The magnitude varies over the surface of the Earth in the range 0.3 to 0.6 Gauss. The Earth's magnetic field is attributed to a dynamo effect of circulating electric current, but it is not constant in direction. Rock specimens of different age in similar locations have different directions of permanent magnetization. Evidence for 171 magnetic field reversals during the past 71 million years has been reported. Although the details of the dynamo effect are not known in detail, the rotation of the Earth plays a part in generating the currents which are presumed to be the source of the magnetic field. Mariner 2 found that Venus does not have such a magnetic field although its core iron content must be similar to that of the Earth. Venus's rotation period of 243 Earth days is just too slow to produce the dynamo effect. Interaction of the terrestrial magnetic field with particles from the solar wind sets up the conditions for the aurora phenomena near the poles. The north pole of a compass needle is a magnetic north pole. It is attracted to the geographic North Pole, which is a magnetic south pole (opposite magnetic poles attract). The simple question "how does the Earth get its magnetic field?" does not have a simple answer. It does seem clear that the generation of the magnetic field is linked to the rotation of the earth, since Venus with a similar iron-core composition but a 243 Earth-day rotation period does not have a measurable magnetic field. It certainly seems plausible that it depends upon the rotation of the fluid metallic iron which makes up a large portion of the interior, and the rotating conductor model leads to the term "dynamo effect" or "geodynamo", evoking the image of an electric generator. Convection drives the outer-core fluid and it circulates relative to the earth. This means the electrically conducting material moves relative to the earth's magnetic field. If it can obtain a charge by some interaction like friction between layers, an effective current loop could be produced. The magnetic field of a current loop could sustain the magnetic dipole type magnetic field of the earth. Large-scale computer models are approaching a realistic simulation of such a geodynamo. That is my best guess.
