From the Helmholtz Association of German Research Centres
Rapid changes in the Earth’s core: The magnetic field and gravity from a satellite perspective
Annual to decadal changes in the earth’s magnetic field in a region that stretches from the Atlantic to the Indian Ocean have a close relationship with variations of gravity in this area. From this it can be concluded that outer core processes are reflected in gravity data. This is the result presented by a German-French group of geophysicists in the latest issue of PNAS (Proceedings of the National Academy of Sciences of the United States).
The main field of the Earth’s magnetic field is generated by flows of liquid iron in the outer core. The Earth’s magnetic field protects us from cosmic radiation particles. Therefore, understanding the processes in the outer core is important to understand the terrestrial shield. Key to this are measurements of the geomagnetic field itself. A second, independent access could be represented by the measurement of minute changes in gravity caused by the fact that the flow in the liquid Earth’s core is associated with mass displacements. The research group has now succeeded to provide the first evidence of such a connection of fluctuations in the Earth’s gravity and magnetic field.
They used magnetic field measurements of the GFZ-satellite CHAMP and extremely accurate measurements of the Earth’s gravity field derived from the GRACE mission, which is also under the auspices of the GFZ. “The main problem was the separation of the individual components of the gravity data from the total signal,” explains Vincent Lesur from the GFZ German Research Centre for Geosciences, who is involved in the study. A satellite only measures the total gravity, which consists of the mass fractions of Earth’s body, water and ice on the ground and in the air. To determine the mass redistribution by flows in the outer core, the thus attained share of the total gravity needs to be filtered out. “Similarly, in order to capture the smaller changes in the outer core, the proportion of the magnetic crust and the proportion of the ionosphere and magnetosphere need to be filtered out from the total magnetic field signal measured by the satellite,” Vincent Lesur explains. The data records of the GFZ-satellite missions CHAMP and GRACE enabled this for the first time.
During the investigation, the team focused on an area between the Atlantic and the Indian Ocean, as the determined currents flows were the highest here. Extremely fast changes (so-called magnetic jerks) were observed in the year 2007 at the Earth’s surface. These are an indication for sudden changes of liquid flows in the upper outer core and are important for understanding the magneto-hydrodynamics in the Earth’s core. Using the satellite data, a clear signal of gravity data from the Earth’s core could be received for the first time.
This results in consequences for the existing conceptual models. Until now, for example, it was assumed that the differences in the density of the molten iron in the earth’s core are not large enough to generate a measurable signal in the earth’s gravitational field. The newly determined mass flows in the upper outer core allow a new approach to Earth’s core hydrodynamics.
“Recent changes of the Earth’s core derived from satellite observations of magnetic and gravity fields”, Mioara Mandea, Isabelle Panet, Vincent Lesur, Olivier de Viron, Michel Diament, and Jean-Louis Le Mouël, PNAS 2012; doi:10.1073/pnas.1207346109
http://www.pnas.org/content/early/2012/10/11/1207346109.full.pdf
I plotted the path of magnetic north during the 41kya reversal on the current geoid and it basically hopped between gravity holes.
http://wp.me/p1uHC3-5P
Electrets, like magnets, are dipoles. Another similarity is the radiant fields: They produce an electrostatic field (as opposed to a magnetic field) around their perimeter.”
for any 
outside of the sphere.
Nothing impossible going on here.
Dear Zeke,
Wrong. Geometrically wrong. Look, if you understand Gauss’s Law, you understand why this is impossible. If you understand Dirac’s construction of a “magnetic monopole” out of magnetic dipoles, you’d understand even more, why the best possible attempt involves introducing a topological defect. If you don’t understand these things, why try to correct me when I have taught both graduate and undergraduate electrodynamics for over thirty years and written two books on the subject?
My Ph.D. dissertation was basically an application of multipolar methods in quantum mechanics. My graduate textbook has the world’s best description (one of the only full derivations and descriptions) of the use of consistently defined and derived vector multipoles for describing the electromagnetic field. I routinely teach even undergraduates the importance of both monopoles and dipoles in even an elementary description of electricity and magnetism.
You’re not going to be able to correct me here, not because I’m a mean or stupid person, not because I’m participating in a great conspiracy to defend warmists, not because I’m hostile to iconoclastic but physically plausible ideas, but rather because the proposition is absurdly stupid and anybody who understands even introductory electromagnetism at all well can see why. It’s one of the first things one teaches students when introducing the multipolar series (monopole, dipole, quadrupole etc) as a means of describing electric or magnetic or electromagnetic fields in terms of integral moments over the charge distribution.
So let me say it clearly and distinctly, so that there is no mistake. There… is… no… way… to… make… a… monopole… out… of… dipoles….
None. Cannot be done. It violates Gauss’s Law. The best possible effort in this regard is Dirac’s construction of a magnetic “monopole” out of a vector potential that produces a monopolar field in all space except on a defect line. Ever heard of that? Able to write down the vector potential in question and prove that the field is monopolar except on the defect line? Understand how the resulting field does NOT violate Gauss’s Law? Of course not, but that is one of the homework problems I often assign in graduate E&M.
This is also nothing at all like “arranging a bunch of dipoles on the surface of a sphere with their negative charges pointing in and their positive charges pointing out”, as described in the crank site linked above. If you understood even the SIMPLEST bits of E&M, you’d recognize that the electrostatic field satisfies the superposition principle, so that the field outside of the sphere is the vector sum of the fields of the equal and opposite electric charges in the dipoles and rigorously vanishes in the limit that you e.g. create a uniform dipolar surface layer of charge, and never ever varies like
So once again. Wrong. Please don’t be a crank or endorse crankery. There are too damn many cranks out there; it makes the mere iconoclasts difficult to identify.
rgb
gymnosperm says: October 26, 2012 at 7:13 am
…….
Currently there is a bifurcation of geo-magnetic field in the Northern hemisphere in contrast to uniformity of the ‘south pole’s field’. Hence in the NH ‘dip needle’ identifies resultant vector, however the strongest field since mid 1990s is found in the central Siberia, to the north of lake Baikal. Prior to 1990s strongest field was in the vicinity of Hudson Bay.
http://www.ngdc.noaa.gov/geomag/data/mag_maps/pdf/F_map_mf_2010.pdf
During last 100 years the Hudson Bay has been on decline, while Siberia is getting stronger
http://www.vukcevic.talktalk.net/NFC.htm
rgb – on a side note here if you please. What is your take on the magnetic portals that supposedly form every 8 minutes that provide a direct pathway between the earth and sun? Obvioulsy we know electric currents flow through them hence the magnetism. But what do you suppose the influence is from these portals and how they may affect things on the surface on the sun like sunspot intensity, or perhaps the earths magnetic field?
rgb – on a side note here if you please. What is your take on the magnetic portals that supposedly form every 8 minutes that provide a direct pathway between the earth and sun? Obvioulsy we know electric currents flow through them hence the magnetism. But what do you suppose the influence is from these portals and how they may affect things on the surface on the sun like sunspot intensity, or perhaps the earths magnetic field?
I don’t have a take on them because I’ve never heard of them until just now. The NASA site calls them FTEs — “flux transfer events”. I’m guessing — very much guessing as I only just looked at one not terribly technical article on them — that they are the results of magnetohydrodynamic instabilities that pinch off the solar magnetic field from the Earth’s magnetic field as everything rotates and revolves, but then reconnects the flux lines. There may be some sort of coupled capacitative effect involved too — charged particles build up when it is closed that are responsible for reopening/reconnecting the flux lines. But magnetic fields produced by things like plasmas are very, very complex and highly nonlinear, and I’m not an expert even on the solutions that we know (let alone the ones that we can’t solve for, only observe). I’ll leave that for somebody like Lief that no doubt lives and breathes plasma physics and magnetohydrodynamics. That’s all a few thousand degrees K above my areas of expertise…;-)
rgb
Hi Dr.Brown
It is a bit of NASA hype about geomagnetic storms (magnetic portals, magnetic ropes, magnetic cloud)
http://www.youtube.com/watch?v=_BHFp7X8TDg
http://wwwppd.nrl.navy.mil/prediction/cloud.html
http://wwwppd.nrl.navy.mil/prediction/storms.html
For grins, short problem 6 from my review guide for first year intro E&M:
, approximately what magnetic field will Roger observe one meter away from his “monopole”? Why? (Draw a picture, invoke a law, something…).
. It is zero because the magnetic field lines form closed loops that run through the actual magnetics. Hence the magnetic flux through a closed surface a meter away must vanish (a.k.a. Gauss’s Law for Magnetism, one of the homogeneous Maxwell Equations) — the outgoing field must equal the incoming field. The field won’t quite be zero as the bar magnets or refrigerator magnets are discrete and their fields won’t precisely line to cancel up so there will be a very weak “ripple” at that radius with zero total flux and very, very weak field strength, but zero is by far the best answer.
problems/short-build-a-monopole.tex
Roger (who we can imagine owns a motorcycle repair shop in Morehead City)
hears about magnetic monopoles and decides to build one and end all the confusion. He gets a few hundred bar magnets and glues them all hedgehog-fashion
onto an iron sphere 10 cm in radius so that the north poles face out and the sphere is tightly packed and covered. He reasons that the field of the south poles will meet in the middle and cancel out, while the north pole fields will look just like a monopole.
If the total summed pole strengths (“magnetic charge” of the north poles as determined by their magnetic dipole moments) of all the bar magnets is
The answer is “zero”, not
The exact same thing is true for electric fields produced by physical electric dipoles (made with actual physically separated electric monopoles), only worse. In this case one can indeed make a nearly perfect “surface layer” of dipoles, such as a conducting sphere with negative charge inside and concentric with a conducting sphere of slightly larger radius with positive charge, which is the limiting case of Zeke’s “radially packed electrets” — only now it is a perfect textbook case, covered in every single book on introductory electromagnetism in the world — a spherical capacitor. Here is the proof that the field outside is zero:
therefore
Wow, is that so difficult?
rgb
OK, sorry, nailed once again by the cosmic lack of an “edit” or “preview” button such as those found on Slashdot or Goodreads. So moderator, if you could remove the superfluous boldface markup. I’ll try a second time to fix the Gauss’s Law instance here:
rgb
vukcevic says:
October 26, 2012 at 2:31 pm
Hi Dr.Brown
It is a bit of NASA hype about geomagnetic storms (magnetic portals, magnetic ropes, magnetic cloud)
Perhaps – Still these portals with electric current flowing
between sun and earth, and that earth’s ionosphere and surface –
separated by an insulating atmosphere – behaves like a leaky
capacitor that regularly charges up from the sun and breaks down –
could make the connection to phenomena like sprites and elves,
poorly understood plasma phenomena occurring high in the
atmosphere.
Thank you. The only reason I said anything is because you put a little too much mustard on your personal attacks on the physicists who have worked on the question of why matter has mass.
Each atom’s nucleus is very weakly offset towards the center of the planet. No monopoles are discussed. The planet itself is an electret. Electrets were discovered in 1733 by Stephen Gray and rediscovered by Dr. Mototaro Eguchi in the 20’s, and some of his wax electrets still have thier charge, and possess a N & S pole. Mass and gravity are both happening at an atomic level in this model. I wanted to give a simpler and accurate representation of what was being said than what you gave, but let’s not bicker then as you say.
If you can help me, Dr Brown, I would like to ask you what the final cost of CERN has been, including maintenance, power, and repairs, to date. I have tried to find this through searches, and would appreciate anything you can tell me.
PS Regarding imparting mass with the God particle, W. Thornhill writes, “the Higgs particle is like no other in our experience, since all normal matter is composed of electric charges that respond to electromagnetic influences… However, we observe that the mass of a charged subatomic particle is altered by the application of electromagnetic forces. At its simplest (and Nature is economical in our experience) it indicates that mass is related to the storage of energy within a system of electric charges inside the particle. That’s what E = mc2 is telling us. So how can a massive particle be constructed without electric charge? It shows the problem inherent in leaving physics to mathematicians — there is a disconnect between mathematical concepts and reality.
The notion that subatomic particles exhibit mass as a result of their interaction with imaginary Higgs particles occupying all of empty space like some form of treacle should have caused a sceptical uproar, if it weren’t for the appalling apathy of the public toward such nonsense. The ‘annihilation’ and ‘creation’ of matter is invoked when particles at particular points arise from ‘fields’ spread over space and time. Higgs found that parameters in the equations for the field associated with his hypothetical particle can be chosen in such a way that the lowest energy state of that field (empty space) is not zero. With the field energy non-zero in empty space, all particles that can interact with the Higgs particle gain mass from the interaction.
This explanation for the phenomenon of mass should have been stillborn if common sense was used. To begin, the annihilation and creation of matter is forbidden by a principle of physics. It is tantamount to magic. Second, field theory is a purely imaginary construct, which may or may not have physical significance. And third, it is not explained how the Higgs particle can have intrinsic mass but no charge and yet interact with normal matter, which has charge but is said to have no intrinsic mass. Rather than explain the phenomenon of mass, the theory serves to complicate and confuse the issue. The most amazing feature of this $6 billion experiment is the confused and illogical thinking behind it.”
Zeke, until you have a teensy weensy clue about Maxwell’s equations and the electrostatic field, I would strongly suggest that you abandon suggesting that the earth is an electret or any other utter nonsense of that general variety. Indeed once you have actually learned electrodynamics and a half dozen other things you might — might, I say — be qualified to talk about why particles have mass. Or charge. Or spin. Or almost any other intrinsic property.
. I repeat, the reason is called “Gauss’s Law”, which should make it really easy to look up in my or other online physics textbooks. In the meantime, your “theory” just makes you look silly, and when you offer it as a reason that the Higgs boson doesn’t exist — very probably offering it some months after it has been actually observed, to top if off — it makes you look very silly.
However, you clearly do not have such a clue. If you did, you would understand — or at least, take the time to learn — why charge-neutral matter cannot have a radial electrostatic field that drops off like
Kind of like a crank.
Please stop.
rgb