First measurement of magnetic field in Earth’s core

Image: NASA

Earth’s internal dynamo generates average field in outer core 50 times that at surface

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.

“This is the first really good number we’ve had based on observations, not inference,” said author Bruce A. Buffett, professor of earth and planetary science at UC Berkeley. “The result is not controversial, but it does rule out a very weak magnetic field and argues against a very strong field.”

The results are published in the Dec. 16 issue of the journal Nature.

A strong magnetic field inside the outer core means there is a lot of convection and thus a lot of heat being produced, which scientists would need to account for, Buffett said. The presumed sources of energy are the residual heat from 4 billion years ago when the planet was hot and molten, release of gravitational energy as heavy elements sink to the bottom of the liquid core, and radioactive decay of long-lived elements such as potassium, uranium and thorium.

A weak field – 5 Gauss, for example – would imply that little heat is being supplied by radioactive decay, while a strong field, on the order of 100 Gauss, would imply a large contribution from radioactive decay.

“A measurement of the magnetic field tells us what the energy requirements are and what the sources of heat are,” Buffett said.

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. This constantly builds up crud in the outer core.

The Earth’s magnetic field is produced in the outer two-thirds of the planet’s iron/nickel core. This outer core, about 1,400 miles thick, is liquid, while the inner core is a frozen iron and nickel wrecking ball with a radius of about 800 miles – roughly the size of the moon. The core is surrounded by a hot, gooey mantle and a rigid surface crust.

The cooling Earth originally captured its magnetic field from the planetary disk in which the solar system formed. That field would have disappeared within 10,000 years if not for the planet’s internal dynamo, which regenerates the field thanks to heat produced inside the planet. The heat makes the liquid outer core boil, or “convect,” and as the conducting metals rise and then sink through the existing magnetic field, they create electrical currents that maintain the magnetic field. This roiling dynamo produces a slowly shifting magnetic field at the surface.

“You get changes in the surface magnetic field that look a lot like gyres and flows in the oceans and the atmosphere, but these are being driven by fluid flow in the outer core,” Buffett said.

Buffett is a theoretician who uses observations to improve computer models of the earth’s internal dynamo. Now at work on a second generation model, he admits that a lack of information about conditions in the earth’s interior has been a big hindrance to making accurate models.

He realized, however, that the tug of the moon on the tilt of the earth’s spin axis could provide information about the magnetic field inside. This tug would make the inner core precess – that is, make the spin axis slowly rotate in the opposite direction – which would produce magnetic changes in the outer core that damp the precession. Radio observations of distant quasars – extremely bright, active galaxies – provide very precise measurements of the changes in the earth’s rotation axis needed to calculate this damping.

“The moon is continually forcing the rotation axis of the core to precess, and we’re looking at the response of the fluid outer core to the precession of the inner core,” he said.

By calculating the effect of the moon on the spinning inner core, Buffett discovered that the precession makes the slightly out-of-round inner core generate shear waves in the liquid outer core. These waves of molten iron and nickel move within a tight cone only 30 to 40 meters thick, interacting with the magnetic field to produce an electric current that heats the liquid. This serves to damp the precession of the rotation axis. The damping causes the precession to lag behind the moon as it orbits the earth. A measurement of the lag allowed Buffett to calculate the magnitude of the damping and thus of the magnetic field inside the outer core.

Buffett noted that the calculated field – 25 Gauss – is an average over the entire outer core. The field is expected to vary with position.

“I still find it remarkable that we can look to distant quasars to get insights into the deep interior of our planet,” Buffett said.

###

 

The work was funded by the National Science Foundation.

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73 thoughts on “First measurement of magnetic field in Earth’s core

  1. Whoooo hoooo! Structure of our planet is first out of the chute when we come back from our Christmas holiday. Perfect lead-in!

  2. Interesting indeed. I don’t quite understand how you can have a frozen inner core of iron and nickle surrounded by a molten core of iron and nickle. I’m thinking the inner core is something else besides frozen.

  3. “I still find it remarkable that we can look to distant quasars to get insights into the deep interior of our planet,” Buffett said.

    So do I! Quite amazing. but I do worry about his approach “based on observations, not inference” certainly not the mannly thing to do.

  4. Can we get the climatologists to model this and its effects on climate 1,000 years into the future so that we can start panicking now?

    Seriously, though, I would love to see how the gravitational component decays over time. Or has this ended and is the core now in the cooling phase?

    TGIF

  5. jack morrow, it’s because of pressure. Pressure at the inner core is estimated at around 350 GPa (billion pascals), and at that pressure the primary elements of nickel and iron solidify.

  6. First we should ask ourselves why does magnetism occur with preference with Iron, Nickel and Cobalt, that share in common having +2 and +3 valences, changing of oxidation states in between the two ( a current), specially in iron magnetite (FeO+Fe2O4=Fe3O4).
    We are lacking the vision of a general law, which manifests everywhere and, however, it is not found anywhere. Curious.

  7. Motion of a conductor through a magnetic field generates a current that has been perpetuating the magnetic field for billions of years after the original field has dissipated.

    The government should do something.

  8. “This is the first really good number we’ve had based on observations, not inference,”

    A novel concept.

    “You get changes in the surface magnetic field that look a lot like gyres and flows in the oceans and the atmosphere, but these are being driven by fluid flow in the outer core,”

    Anybody got about eleven trillion tons of iron powder? Sounds to me like we could have one hell of a (nearly-)spherical Etch-a-Sketch here.

  9. …but I do worry about his approach “based on observations, not inference” certainly not the mannly thing to do.

    [groan]

    Good one anyway. :-)

  10. what gets me is that this guy shows that as a real scientist he has a hard time making models without observations to verify them, wish climate science had those issues.

  11. The inner core can be frozen whilst surrounded by a hotter liquid because it is under higher pressure. Water is very unusual in that it expands on freezing, almost all other liquids can be made to ‘freeze’ by pressure so an ocean of petrol say would become solid within a few hundred feet of the surface.

  12. Related news from a couple of days ago from Hebrew University, via Wired:

    “Iron Age Copper Reveals Earth’s Stronger, Faster Magnetic Field”

    http://www.wired.com/wiredscience/2010/12/magnetic-copper-slag/

    SAN FRANCISCO — Slag left over from Iron Age copper smelting shows the Earth’s magnetic field was stronger and more variable than scientists ever imagined.

    “This is a very challenging result,” said geomagnetist Luis Silva of the University of Leeds, who was not involved in the new work. “It’s completely outside of anything we thought could be happening in the core.”

    The Earth’s magnetic field comes from the movement of molten iron in the core. The field’s strength and structure are constantly changing. But paleomagnetists (scientists who study the history of the Earth’s magnetic field) thought the changes were usually small and slow, fluctuating by about 16 percent over the course of a century.

    But a new study of ancient copper mines in southern Israel found that the strength of the magnetic field could double and then fall back down in less than 20 years.

    “The magnetic field reached an intensity that was much higher than anyone had ever thought before, two and a half times the present field,” said graduate student Ron Shaar of the Hebrew University of Jerusalem, lead author of the new study. “And you can have dramatic changes in the intensity of the field in periods of less than decades.” Shaar presented his results in a poster here at the American Geophysical Union meeting Dec. 14, and in a paper to appear in Earth and Planetary Science Letters.

    OK S.

  13. Re: “The cooling Earth originally captured its magnetic field from the planetary disk in which the solar system formed.”

    This is what we call “new physics.” Notice that the reporter completely fails to mention that this is a hypothesis.

    Re: “That field would have disappeared within 10,000 years if not for the planet’s internal dynamo, which regenerates the field thanks to heat produced inside the planet.”

    A problem created by the conventional framework itself …

    Re: “The heat makes the liquid outer core boil, or “convect,” and as the conducting metals rise and then sink through the existing magnetic field, they create electrical currents that maintain the magnetic field. This roiling dynamo produces a slowly shifting magnetic field at the surface.”

    Never mind the observation that we see lightning going to space now, and that each time a lightning stroke occurs, the Van Allen Radiation Belts blink.

    Re: “You get changes in the surface magnetic field that look a lot like gyres and flows in the oceans and the atmosphere, but these are being driven by fluid flow in the outer core,” Buffett said.

    Electrical processes are always second-order effects in the conventional theories.

    Re: “Buffett is a theoretician who uses observations to improve computer models of the earth’s internal dynamo. Now at work on a second generation model, he admits that a lack of information about conditions in the earth’s interior has been a big hindrance to making accurate models.”

    In science, we are supposed to be skeptical of concepts which are invisible and theoretical. Philosophy of science dictates that we — reporters included — speak in terms which are unbiased, and hold out for the possibility that our assumptions might be wrong.

    One need not be a professional scientist to determine the philosophical errors here. These guys are pretending as though philosophy of science does not even exist.

  14. Magnetic reversals. Are we not overdue for one?
    The magnetic field is weaking, or so I have read.
    Would another reading in a year or so confirm the direction?

  15. I don’t know what “philosophy of science” is. Maybe that’s like the theory of science as opposed to the practice of science. I do know what the difference between philosophy and science is. Philosophy came first. It is pure speculation, attempting to think or “reason” about things, what we would now call “hand-waving”. If you add to that better logic, mathematics and even statistics, experiments, ways to falsify claims, an attempt to separate claims from facts, then you start to have science. The problem with “climate scientists” is that many of them are at best philosophers not real scientists. They might as well be science-fiction writers or the priests of a new religion. end rant.

  16. Diameter of earth approx 12.000 kilometers
    Deepest borehole approx. 12 kilometers

    So. We have ‘observed’ the composition of earth two thousands (0.2 %) of the way down towards the center. What would we be able to say about an apple or a an animal cell if we only could study a small part of the way into the peel/cell membrane ?

  17. I didn’t really intend to be this active a poster on my first day, but I find it interesting that the potential for serious effects on civilization lie in the periodic fading of the Earth’s magnetic field (we are quite overdue for the next “outage”, apparently) exceeds in some respects any of those speculated to arise from climate change. Homing pigeons, I cry for you!

    http://en.wikipedia.org/wiki/Geomagnetic_reversal

  18. An interesting hypothesis, but only a hypothesis. Earth’s magnetic field has number of anomalies that the above would have difficulty in explaining.
    Magnetic field in the North hemisphere behaves in totally different manner to the south. I would assume Moon would act equally on both. North hemisphere field has reversed correlation to the solar, but precedes it by about one Hale cycle, while the south is ~ logarithmic decay.

    http://www.vukcevic.talktalk.net/LFC9.htm

    It would be indeed strange if the Moon modulated sunspot cycle.
    I have no idea what and how the Earth’s field is generated, but I am a bit sceptical of people who claim that they know. This bit of science is the long way from being settled.

  19. Helge
    December 17, 2010 at 9:39 am
    “So. We have ‘observed’ the composition of earth two thousands (0.2 %) of the way down towards the center.”
    ###

    Um, no. Mankind has made “observations” of the interior of the planet all the way to the core.

  20. Chris,

    That’s pretty much the norm in science reporting anymore. Try reading an article (or worse yet, watching a “Science” channel show) on String Theory.

  21. I would suggest modifying your title, Anthony.

    First, this is not a measurement of the Earth’s core magnetic field. This is an inference of the Earth’s core magnetic field based on other measurements. Not the same thing. We cannot measure the Earth’s magnetic field within the core without inserting some sort of probe into it. Let me know when you figure that one out.

    Second, this is not the first time that the strength of the magnetic field within the core has been inferred. It’s been done many times before, under a whole variety of assumptions. Here’s an example, again from Nature, that was published just a few months ago:

    http://www.nature.com/nature/journal/v465/n7294/full/nature09010.html

    TOS

    REPLY: The title is the one from the press release, not mine. See http://www.berkeley.edu/news/media/releases/2010/12/16_earth_magnetic_field.shtml
    -Anthony

  22. Richard G says:
    December 17, 2010 at 10:31 am
    You can also know when an earthquake it is about to happen by having this Ipod App:

    http://itunes.apple.com/us/app/gravity-meter/id358324984?mt=8

    During an earthquake the acceleration of gravity varies. During the Feb.27 2010 8.9 degrees Richter earthquake a watchman and his wife knew it was one coming because in the school he work it has been installed an accelerator connected to a siren, so they went out 5 minutes before the earthquake. They were about to get back inside the building when it started the “fun”.
    All fields are related, though current water tight compartments between branches of science and prejudices avoid the recognition of this fact. (you can also click on my link, above)

  23. Re: “I don’t know what “philosophy of science” is. Maybe that’s like the theory of science as opposed to the practice of science. I do know what the difference between philosophy and science is. Philosophy came first. It is pure speculation, attempting to think or “reason” about things, what we would now call “hand-waving”.”

    Hand-waving is what happens when there is no philosophy behind a thinker’s actions. We all intuitively understand what philosophy of science is. It’s what keeps scientists fair and objective about their research. It’s not so much a set of rules, as it is a general guide (or way of doing business) which keeps scientists from casting their own human preferences and prejudices onto their methodologies, assumptions, inferences and conclusions. Our theories are supposed to be “pure” of human likes and dislikes, as they are supposed to reflect things like data and logical arguments. A human preference can be thought of as the antithesis of philosophy of science.

    Philosophy of science is most important at the point of the inferential step. All humans possess prejudices and preferences for theories, based upon our reading selection and education. But, the peer review process and the scientific method are, in theory at least, supposed to be above all of that. So, philosophy of science is all that protects our theories from our own human failings. Scientists who ignore it will tend to just ignore those inferences which they don’t like, and only consider those which they do. If you ever happen to pick up a book on philosophy of science, you will see them discuss concrete examples where this has historically occurred. Whenever you hear a scientist say, “We’ve ruled everything out except …”, this is when red flags should go off, because they assume the conventional theories to begin with for just about ALL research that goes on today. It would be more proper to state:

    “Assuming the conventional framework (Lambda CDM, the Standard Solar Model, etc.), we can rule out everything but …”

    Re: “If you add to that better logic, mathematics and even statistics, experiments, ways to falsify claims, an attempt to separate claims from facts, then you start to have science.”

    But, without a philosophy, there is potential for abuse. For instance, if they refuse to read or listen to arguments which they disagree with, while simultaneously demanding that the burden of proof is upon those making competing claims to prove their case, they’ve just created an impossible situation for novel, competing ideas. We should all be able to agree that there exists no philosophy in this approach, as it favors one theory — the dominant one — over all others. In this particular case, philosophy of science prevents science from stagnating.

    Another example is cosmic microwave background. A philosophical approach to science dictates that theorists must be willing to consider all potential inferences which are “physical” before considering those which are more “meta-physical”. So, when cosmologists saw an electromagnetic fog of microwaves coming at the Earth from all directions, they opted to infer that this was a relic of a primordial explosion which created all of time and space. However, had they stepped into a plasma laboratory and done experiments on plasma beams — which they knew at that time was the universe’s preferred state for matter — they would have also realized that plasma beams always emit microwaves. Plasmas emit spikey synchrotron instead of a smooth black body bell curve, but does it really matter? Thermalizing this synchrotron into a bell curve is not a meta-physical inference. Imagining that you’re seeing a relic of a primordial explosion which created matter, time and space certainly IS.

    There are numerous examples which I could point to. The point is that, with philosophy as a guide, we can better see the larger context for how to evaluate cosmologies. Without philosophy, we are forced to compare one cosmology on the basis of another without any guide to keep us honest. And since cosmologies can present dramatically different types of evidence to begin with, this latter misinformed approach will ultimately be nothing more than an expression of our human preferences and prejudices.

    Re: “The problem with “climate scientists” is that many of them are at best philosophers not real scientists. They might as well be science-fiction writers or the priests of a new religion. end rant.”

    I see and agree with what you’re saying, but I would prefer to use a different word than “philosophers”. Before humans started breaking the scientific disciplines up into pieces, scientists like James Maxwell were called “natural philosophers”. It’s a great term because it reminded every one of them that scientists are bound to the philosophical thinking which happened many years ago in Greece, which has served as the fundamental basis for much of our modern-day thinking.

    Modern-day climate science and even modern-day cosmology are NOT based upon this solid philosophical foundation. Astrophysicists also make a number of very serious philosophical errors in their own analysis.

  24. kuhnkat says:
    December 17, 2010 at 8:41 am

    Frozen means solid and colder than the outer liquid layer!!!

    Not sure if the term “frozen” means anything more than just “solid.” As I understand it, the core is in a solid state simply due to the intensely high pressure, but is still at an extremely high temperature. Am I wrong?

  25. Toto says: “I don’t know what ‘philosophy of science’ is.”

    The philosophy of science is the methodology or process of coming to a scientific understanding. It’s also called natural philosophy.

    Principly, it means empirical observation & measurement of actual physical events is the road to correctly understanding those physical events.

    A priori assumptions lead to errors in scientific understanding.

    “CO2 is what causes warming,” is an example of an a priori assumption.

  26. According to this model, how does an Earth magnetic field survive hundreds of polarity reversals as well documented in the geologic column? One would think a quick dampening of the dynamo would result.

    I cannot help but think there are some high-pressure, high-temperature physics going on we know little about.

  27. I used to work on Earth rotation, and remember when it wasa first suggested that distant quasars could be used as a precise indicator of irregularities in the Earth’s motion. Congratulations to the radio astronomers who devised this procedure, and to those who have used it to investigate the nature of the planet’s magnetic field.

  28. Re: ““The magnetic field reached an intensity that was much higher than anyone had ever thought before, two and a half times the present field,” said graduate student Ron Shaar of the Hebrew University of Jerusalem, lead author of the new study. “And you can have dramatic changes in the intensity of the field in periods of less than decades.” Shaar presented his results in a poster here at the American Geophysical Union meeting Dec. 14, and in a paper to appear in Earth and Planetary Science Letters.”

    It’s worth noting that within the plasma-based cosmologies, that two cosmic bodies which approach one another will eventually charge-neutralize with one another. And one has to imagine that these enormous electrical discharges will show up in the geologic record as dramatic changes in the magnetization of Earth’s rocks.

    What they are seeing is arguably evidence for global catastrophe. It’s further evidence that we should be abandoning the uniformitarian view which theorists to this day still cling to. For those still taking count after all of these years, Velikovsky is actually winning some of these really old catastrophist debates.

  29. Toto says:
    December 17, 2010 at 9:37 am

    They might as well be science-fiction writers or the priests of a new religion. end rant.
    ###

    You are way off base here. Before you start insulting something you should at least have some idea of what you are talking about. You seem to be very ignorant of the nature of actual science-fiction; confusing it with that socialist crap praised by the lefties, written by authors who might write one pseudo SF story in their entire life (and wear ugly glasses, to boot). That’s not SF, its socialist propaganda.

    Real SF is based on the extrapolation of REAL science.

  30. Dear Anthony: I asked about this topic a number of weeks/months ago (time flies). Thank you very much for bringing up some information and discussion about it!!

    It seems that the physics 12,000 miles beneath our feet is poorly understood yet is somehow intricately linked with the moon and sun. Our little home in space is built on an amazing foundation.

    Merry Christmas, Happy Holidays and have a wonderful New Year! Jeff

  31. The geomagnetic field is interesting as there are multiple observations which the mainstream mechanism that is hypothesized to generate the geomagnetic field, the self dynamo cannot explain.

    The follow are some of the issues and links to papers for those who are interested in this subject.

    The geomagnetic field protections the earth from loss of water (H2) to the solar wind. It is known that the geomagnetic field is at least 3.5 billion years old. The geomagnetic dynamo mechanism requires a specific heat source that creates a heat gradient to drive convection in the liquid core. That requires that the earth cool to create a heat gradient. The heat gradient is hypothesized to be generated by the solidifying of the core, however, basic analysis indicates the solid core is at most 1 billion years old, based on the current heat loss. That problem is called the heat flux problem or paradox as prior to the core solidifying there is no mechanism to generate a heat gradient.

    http://www.sciencedaily.com/releases/2010/03/100304142236.htm

    http://www.iugg.org/IAGA/iaga_pages/pdf/toulouse2005/david_loper.pdf

    It has been found that the geomagnetic field changes suddenly and that the changes are cyclic. The changes correlate with climate change events. One theory is the climate change causes the geomagnetic field changes (the ice sheet changes are hypothesized to alter core motion) however the cyclic geomagnetic field changes lead rather than follows the climate change and the ice sheet changes are orders of magnitude to small to alter the core. There is currently no accepted mainstream explanation to why the geomagnetic field changes cyclically.

    Recent analysis has confirmed very rapid field changes have occurred in the past which are faster than a core generated field change can produce. The mantel is slightly conductive and hence retards the fast core generating field changes from reaching the surface by generating a counter acting EMF.

    There are periods of 10 millions of years called superchrons when the geomagnetic field no longer reverses. There is no explanation as to why that is so or why the period between geomagnetic field reversals has varied with geological time.

    http://eprints.whiterose.ac.uk/416/1/gubbinsd4.pdf

    “Is the geodynamo process intrinsically unstable?

    Recent palaeomagnetic studies suggest that excursions of the geomagnetic field, during which the intensity drops suddenly by a factor of 5 to 10 and the local direction changes dramatically, are more common than previously expected. The `normal’ state of the geomagnetic field, dominated by an axial dipole, seems to be interrupted every 30 to 100 kyr; it may not therefore be as stable as we thought. We have investigated a possible mechanism for the instability of the geodynamo by calculating the critical Rayleigh number (Rc) for the onset of convection in a rotating spherical shell permeated by an imposed magnetic field with both toroidal and poloidal components.

    Recent studies suggest that the Earth’s magnetic field has fallen dramatically in magnitude and changed direction repeatedly since the last reversal 700 kyr ago (Langereis et al. 1997; Lund et al. 1998). These important results paint a rather different picture of the long-term behaviour of the field from the conventional one of a steady dipole reversing at random intervals: instead, the field appears to spend up to 20 per cent of its time in a weak, non-dipole state (Lund et al. 1998). One of us (Gubbins 1999) has suggested that this is evidence of a rapid natural timescale (500 yr) in the outer core, and that the magnetic field is usually prevented from reversing completely by the longer diffusion time of the inner core (2 to 5 kyr). This raises
    a number of important but difficult questions for geodynamo theory. How can the geomagnetic field change so rapidly and dramatically? Can slight variations of the geomagnetic field affect the dynamics of core convection significantly? If so, is the geodynamo process intrinsically unstable?”

    http://www.ias.ac.in/currsci/apr252003/1105.pdf

    “Furthermore, because the inner and outer core are electrical conductors, the magnetic field within them cannot change arbitrarily. In particular, this field can only diffuse into or out from the solid inner core relatively slowly. The characteristic time scale for the field to change significantly within the inner core is estimated5 as ~ 3 ka. To crudely summarize a very complex situation, numerical simulation indicates that the flow in the outer core is constantly trying to reverse the polarity of the field on the short (~ 100 year) characteristic time scale of its convective circulation.”

    “It is indeed notable that the Laschamp, Mono Lake, and Gothenburg excursions, the three youngest, all occurred just before Heinrich events (Figure 6).

    The Gothenburg excursion occurred in the early part of the Younger Dryas stage46, the brief cooling within the transition from the last glacial maximum to the Holocene. Some studies46,47 reported that the global sea level fell at this time by ~ 10 m for a few centuries before rising again as melting resumed: consistent with the observed growth of the Laurentian, Scandinavian, and Scottish ice sheets 48–52.”

    http://agenda.albanova.se/getFile.py/access?resId=250&materialId=252&confId=2522

    The laboratory attempts to create a self generating dynamo by convection have not been successful. (i.e. An external magnetic field is required to maintain the dynamo.)

    “Early attempts to understand the dynamo action of a liquid conductor were largely
    unsuccessful because only complicated fluid flows can produce the required regeneration of the magnetic field. It is now possible to model the magnetic-induction effects by supercomputer, but not the turbulence of flow in Earth’s outer core nor Earth’s rapid spin rate. Perhaps surprisingly, computer models using greatly simplified assumptions do reproduce aspects of the geomagnetic field such as the dipole, somewhat unrealistic reversals, and parts of the present non-dipole field (Fig. 6).”

    “No, there are very long intervals of time, called superchrons, when there were no reversals. The last one, the Cretaceous normal superchron, was from about 124 million to 80 million years ago.”

  32. A textually dense entry just above, but I think I got the gist.

    An interesting idea is contemplating whether there is a relation between the rapid (in geological terms) dipole shifting of the Earth and equally rapid climate change. Also intriguing is establishing whether external forces affect the dipole shift and perhaps make such a shift a marker for climate variability.

    This entry made me think of about the best science book I’ve ever read:

    One of the mysteries discussed within it is how oxygen rose to an astounding 35% of the atmosphere (it’s currently about 20%) in the age of the dinosaurs. That’s enough to ensure just about every spark going would start a serious fire…and certainly led to today’s vast coal beds.

    One wonders if the Creataceous “superchron” ties in in any fashion to the long slow rise of the toxic oxygen gas to levels that approached those necessary to set the very air on fire.

  33. So, it can be said our planet’s magnetic field is a “Goldilocks” field – not too weak, not too strong, but just about right. Just right for our purposes, anyway.

  34. One shouldn’t leave out that most of the planets have magnetic fields. Earth, Jupiter, & Saturn all have fields that are close to their rotational axis, typ. around 11 deg although Earth’s seems to be moving around quite a bit these days. These three appear to have their internal bar magnet centered with the planet’s center as well as having the directions roughly coinciding. the other two planets with magnetic fields of significant size are Neptune and Uranus. It seems that their internal bar magnets (equivalence used for conceptual understanding) are located well away from being located at their planet’s centers. Also these fields do not align anywhere close to their rotational axes. Note that since Uranus has a rotational axis that is virtually parallel rather than almost perpendicular to the planetary disk, it may well have suffered some catastrophe early on that could have had an effect on its magnetic field but Neptune does not have such evidence yet is quite similar to Uranus’ magnetic field being well off center and not nearly aligned with the rotational axis of the planet.

  35. This is sooooooo incredibly frightening that I have no doubt the “Mann, Jones, Gore & Co. LLC” will use this new finding to scare the socks off Big Oil, Wall Street, the White House, London, Tokyo, and Sidney, oh yes and that EU thing. This is definitely a case of Anthroprogenicaly Induced Universal Collapse (henseforth and evermore, ta da da da, “AIUC”). I have a feeling their speech writers are going to be burning the midnight solar generators, so to speak, and Hollywood and New England Greenies are going to be wearing sackcloth and ashes like there’s no tomorrow. Mind you, THIS IS BIG!!! Once it can be statistically proven via simulations on supercomputers using two demension programs with a few odd variables that this is actually what is going to happen in a few billion years the West will simply have to surrender and go Commie and we will finally be able to start turning things around. Won’t Chairman Big Brother in Peking be proud? (SarcOff)

  36. tapper of spines says:
    December 17, 2010 at 10:56 am
    We cannot measure the Earth’s magnetic field within the core without inserting some sort of probe into it.
    You do not understand what a measurement is. What you are saying is akin to claiming [I'm sure some nuts would actually do that] that we cannot measure the Sun’s temperature without inserting some thermometer into it at the surface.
    The magnetic field we measure at the surface is the field from the core. We are sitting in it. The field decreases with the cube of the distance. So if the field is generated [say] at a quarter of the Earth’s radius from the center, it would at the surface have decreased by a factor of 4*4*4 = 64; if at a third of a radius, the factor would be 3*3*3 = 27; if somewhere in between we would get a factor between 27 and 64, say, ~50, which is about what is observed. No mystery here. What the measurements referred to is saying is that the field is indeed generated about where we thought it would be generated. In other words, it is a really measurement of where the field is generated.

  37. All these assumptions and calculations are misleading. It might be OK if there was a big magnet somewhere in the Earth’s interior in shape of the letter ‘I’ ,but it is not, it is sort of ‘Y’ shape.

    http://www.vukcevic.talktalk.net/MF.htm

    If it is circulation within interior than it the Earth’s core must be highly non-homogeneous.
    If you want to simulate the Earth’s magnetic field then instead of having a simple bar magnet, get 3 bar magnets and join them as per graph in the above link. Than try to imagine how mantle circulation or moon movements can create such configuration.

  38. vukcevic says:
    December 18, 2010 at 11:55 am
    All these assumptions and calculations are misleading. It might be OK if there was a big magnet somewhere in the Earth’s interior in shape of the letter ‘I’ ,but it is not, it is sort of ‘Y’ shape.
    No, what you see at the surface bears little relation to what the field is in the core. The higher order multipoles decrease in strength much faster than the dipole and even the quadrupole.

  39. Leif Svalgaard says:
    December 18, 2010 at 3:10 pm
    vukcevic says:
    December 18, 2010 at 11:55 am
    All these assumptions and calculations are misleading. It might be OK if there was a big magnet somewhere in the Earth’s interior in shape of the letter ‘I’ ,but it is not, it is sort of ‘Y’ shape.
    No, what you see at the surface bears little relation to what the field is in the core. The higher order multipoles decrease in strength much faster than the dipole and even the quadrupole.
    ~
    Vuks, having a hard time getting my iron ball to spin freely in that Y config. I’ll lean towards an H config with the outer uprights being those 2 cylinders with four ends, Andy Jackson was descriibing in “A new turn for Earth’s rotation.” Now my ball is turning freely again. whaaaaaat

    Leif says, The higher order multipoles decrease in strength much faster than the dipole and even the quadrupole.
    ~
    Ok

  40. Leif Svalgaard says:
    December 18, 2010 at 3:10 pm
    Carla says:
    December 18, 2010 at 5:17 pm
    …………….
    What is happening in the Earth’s interior scientist can only speculate, so can the rest of us. I would be inclined to suggest that the geomagnetic field is generated closer to the surface than the deep down in the core. Circulation and vortex forming is governed by the laws of fluid dynamics. According to the present structure of the GMF, there could be 3 local vortices in the upper mantle two in the Northern Hemisphere and one in the South, each creating its own bar magnet. Jackson may be correct about separate circulating entities, but they are more likely to be conical shape then parallel cylinders, with tips of the cones somewhat eccentric, deep down in the core, inclined South American way.

    http://www.vukcevic.talktalk.net/MF.htm

    There you are, you seen it here first; another first for WUWT.
    That should not be difficult to visualise. Doc is bound to say nonsense, but he routinely does that when short of good alternative reasoning.

  41. vukcevic says:
    December 19, 2010 at 12:50 am
    Circulation and vortex forming is governed by the laws of fluid dynamics. According to the present structure of the GMF, there could be 3 local vortices in the upper mantle
    Except that the upper mantle is not fluid. Jackson’s result is an observation, not an inference.

  42. vukcevic says:
    December 19, 2010 at 12:50 am
    Leif Svalgaard says:
    December 18, 2010 at 3:10 pm
    Carla says:
    December 18, 2010 at 5:17 pm
    …………….
    What is happening in the Earth’s interior scientist can only speculate, so can the rest of us. I would be inclined to suggest that the geomagnetic field is generated closer to the surface than the deep down in the core. Circulation and vortex forming is governed by the laws of fluid dynamics. According to the present structure of the GMF, there could be 3 local vortices in the upper mantle two in the Northern Hemisphere and one in the South, each creating its own bar magnet. Jackson may be correct about separate circulating entities, but they are more likely to be conical shape then parallel cylinders, with tips of the cones somewhat eccentric, deep down in the core, inclined South American way.

    http://www.vukcevic.talktalk.net/MF.htm

    ~
    One question Vuks after viewing the image at your link above. Why is it we never see that huge continent called ‘Antarctica’ at the south pole depicted in these intensity field maps?

  43. Leif Svalgaard says:
    December 19, 2010 at 5:35 am
    …………..
    Thanks for pointing the error, word ‘upper’ got in there unintentionally. Not in the link

    http://www.vukcevic.talktalk.net/MF.htm

    with a more detailed discription.
    Anyway, wherever magma happened to be. Jackson has done some great work, but he is wrong about excentric cylinders, not possible in rotating sphere. Conical vortex can easily be initiated by Coriolis forces. See the link above.
    Circulation and vortex forming is governed by the laws of fluid dynamics, and that is same for all fluids, including atmosphere and magma.
    You may have a little problem here: the Earth’s stratosphere is subject to the same Coriolis force, and guess what; it does the same as the magma vortex, you may consider obvious alternative, the gmf has control of stratospheric vortex.

    http://www.vukcevic.talktalk.net/MF-PV.htm

    What do you say? Do I hear ‘coincidence, nonsense etc’, or do you have a more constructive opinion ?

  44. vukcevic says:
    December 19, 2010 at 6:13 am
    you may consider obvious alternative, the gmf has control of stratospheric vortex.
    What do you say? Do I hear ‘coincidence, nonsense etc’, or do you have a more constructive opinion ?

    This is not an ‘obvious alternative’ as it also has to make sense energetically – and it doesn’t. The stratospheric vortex is controlled by upwards-traveling waves from the troposphere.

  45. Leif
    If as you say that “The stratospheric vortex is controlled by upwards-traveling waves from the troposphere.”

    What then is responsible for the regular increases in the temperature, geopotential heights and associated ozone anomalies in the polar stratosphere as seen here:http://www.cpc.noaa.gov/products/stratosphere/strat_a_f/
    and here: http://www.cpc.ncep.noaa.gov/products/precip/CWlink/daily_ao_index/hgt.shtml

    One observes that positive anomalies in ozone, temperature and geopotential heights appear when the Arctic oscillation (AO) index falls. i.e. when surface atmospheric pressure increases.

    Are you saying that planetary waves are responsible for the fall in the AO (or the increase in surface atmospheric pressure that is part and parcel of the fall in the AO)?

    I would be interested in your explanation of the physics behind that conjunction. Does a planetary wave cause a shift of the mass of the atmosphere towards the pole? Could the changing incidence of planetary waves be responsible for the 25mb fall in atmospheric pressure at the south pole between 1948 and 2010.

    And what is a ‘Planetary wave’?

  46. vukcevic, I agree, and I don’t know.

    I always wonder about the iron-nickel core breaking the magnetic lines of flux from the sun. That should cause electrons to flow and also heat because of resistance.

  47. erlhapp says:
    December 19, 2010 at 7:54 am
    ……………….
    At the South Pole 1948 – 2010
    The main field GMFf fell from 60592.6 to 55205.2 nT or 8.9%.
    The vertical component GMFz fell from 58229.6 to 52635 nT or 10%.
    This is partially due to fall in the Earth’s magnetic field, and partially to the drift of the magnetic pole towards Australia.
    At location of the Australian base ‘Commonwealth Bay’ both GMFf and GMFz have equal values and both fell by 3.4 % .
    If you can find pressure differential for the CB station that could be a starting point.

  48. maelstrom the irreverent says:
    December 19, 2010 at 8:59 am
    I always wonder about the iron-nickel core breaking the magnetic lines of flux from the sun.
    You can stop wondering [alway good to have less thing to wonder about, isn't it?] because it doesn’t. The magnetic field [created in the core] can reconnect [40,000 miles away from the Earth] with the Sun’s magnetic field carried to us by the solar wind, and briefly allow the two fields to interact and electric currents to flow in the upper atmosphere.

  49. Leif Svalgaard says:
    December 19, 2010 at 8:58 am
    No, not anymore than my backyard.

    Than you could get some free electricity, by hanging couple of wires in your backyard.
    Google Scholar will give you dozens studies on the subject of the stratospheric ionization.

  50. vukcevic says:
    December 19, 2010 at 9:05 am
    At the South Pole 1948 – 2010
    The main field GMFf fell from 60592.6 to 55205.2 nT or 8.9%.

    And how much did the GMF fall there the past 2000 years? or since 1600?

  51. vukcevic says:
    December 19, 2010 at 9:24 am
    Google Scholar will give you dozens studies on the subject of the stratospheric ionization.
    And on ionization at the surface too. Please don’t pollute the blog with irrelevant stuff you don’t know much about. You can ask if you want to know something.

  52. Re: “I used to work on Earth rotation, and remember when it wasa first suggested that distant quasars could be used as a precise indicator of irregularities in the Earth’s motion. Congratulations to the radio astronomers who devised this procedure, and to those who have used it to investigate the nature of the planet’s magnetic field.”

    The decision to use quasars as some sort of standard candle is in truth a treacherous one, as the issue of where quasars are actually located, regardless of claims that there is nothing to see here, has been an issue of contentious debate for many years now.

    If they are indeed at the distances which conventional theorists infer from their redshifts (near the edges of what we can see), then they exhibit meta-physical brightnesses.

    Don’t forget that Halton Arp was relieved of his telescope time in his study of such objects, since he inferred that these objects could be plainly observed to be affiliated with more local galaxies. Bridge-like filaments, in some instances, can be observed in certain spectra connecting the quasars to their alleged host galaxies. When contradicting Arp’s claims, conventional publications have on occasion published that imagery which contains spectra which do not show the bridge. We all need to wonder why it is that they appear to be misleading people on the evidence?

    Pairs of quasars with similar redshifts can be seen to align with the axes of certain energetic galaxies. Furthermore, the raw redshifts can be inferred to possess *quantized* inherent components. As these quasars age, they appear to take on additional mass, normalize their redshifts and reduce their brightness. One can logically argue that there exists a far less metaphysical inference that there are things happening here which actually illustrate unexpected linkages between mass and electrical charge. The quantization itself suggests some sort of small-scale process happening on a very large scale. To be clear, the set of inferences we’re seeing on this subject in print is definitely constrained by the Big Bang framework.

    The jury is still out on this one, guys.

  53. My understanding is that when continental drift theory was first put forth, it was assumed that land masses were floating above a liquid mantle. Now it is the more accepted theory, and one based on good seismic evidence, that continental drift is caused by subduction and abduction “creep”. It isn’t floating, it’s creeping and crawling around, loosing edge here and gaining it there at different rates.

  54. Leif Svalgaard says:
    December 19, 2010 at 9:38 am
    Please don’t pollute the blog with irrelevant stuff you don’t know much about. You can ask if you want to know something.

    You are often wrong as in this case of the stratosphere ionisation (and there is great deal of difference between stratosphere and the surface !).
    When I don’t know something I do not ask (implies an answer from a person, whose competency can’t be guarantied), I read number of scientific articles on the subject. Google scholar is particular good search engine.
    Rest of your comment I shall gladly disregard.

  55. Chris Reeve says:
    December 19, 2010 at 9:42 am
    If they are indeed at the distances which conventional theorists infer from their redshifts (near the edges of what we can see), then they exhibit meta-physical brightnesses.
    They are indeed very bright, but not meta-physically so. There are good physical reasons for their brightness. That the quasars are very distant can be seen directly from the gravitational lensing by far-away galaxies: http://apod.nasa.gov/apod/ap060524.html

  56. @Enneagram December 17, 2010 at 11:19 am:

    Richard G says:
    December 17, 2010 at 10:31 am
    You can also know when an earthquake it is about to happen by having this Ipod App:

    http://itunes.apple.com/us/app/gravity-meter/id358324984?mt=8

    During an earthquake the acceleration of gravity varies. During the Feb.27 2010 8.9 degrees Richter earthquake a watchman and his wife knew it was one coming because in the school he work it has been installed an accelerator connected to a siren, so they went out 5 minutes before the earthquake.

    Enneagram, When this says an “accelerator,” they mean an accelerometer. That is what I thought they meant, and that is what the link talked about.

    I’ve worked a small bit with accelerometers (long ago), and normal accelerometers measure increasing or decreasing MOVEMENT. They don’t have to be measuring changes in the gravitational force. In fact, I doubt very seriously if that is what they are doing. My best understanding is that the ground started moving subtly before the quake, accelerating the building the accelerometer was mounted within. The accelerometer did what it is supposed to do – indicate that the building moved.

    I mean, that is a good application for an accelerometer, if the one they used was sensitive enough, which it was. Thinking about it, I am a bit surprised no one has thought to use them for that before. In a practical sense. Geologists probably use them around volcanoes. If they have not used them for quakes before, I’d be shocked. But if they did, why would they be scratching their heads over how to predict quakes shortly before they happen? I REALLY don’t think many quakes happen without some motion just beforehand. Maybe I am wrong on that, though…

    My point here is that I think these people are misunderstanding what the accelerometer indicates/measures.

  57. Re: “They are indeed very bright, but not meta-physically so. There are good physical reasons for their brightness. That the quasars are very distant can be seen directly from the gravitational lensing by far-away galaxies: http://apod.nasa.gov/apod/ap060524.html

    You could have asked for an image of the bridge.

    But, instead, you proposed an inference to explain an inference. And not only that, but gravitational lensing oftentimes lacks sufficient baryonic matter to mathematically work. So, to make it so, theorists will oftentimes sprinkle in some dark matter to glue the theory to the data.

    This is not science, guys.

    One would think that advocates for gravitational lensing would be producing sequences of imagery which demonstrate a lensing effect over time, but what we usually get instead is a single snapshot. Why is that?

    This quote must unfortunately remain unattributed, but the sources are there for everybody to double-check …

    “[T]here is strong reason to doubt that the ‘object at the very center of our galaxy’ is a black hole. According to gravitational astronomers, such a black hole should produce a gravitational lensing effect, particularly for the star S2 which is in orbit around Sagittarius A*. Time resolved images of a number of rapidly moving stars in this area have been available since 1992. See for example R. Schoedel et al, “A star in a 15.2 year orbit around the supermassive black hole at the centre of the Milky Way,” Nature 419 (2002), pp.694-696.

    It is at this point that a presentation by E.H. Dowdye Jr. at the NPA conference in June assumes some significance. He noted that today’s observational tools should easily detect such lensing effects of a black hole of the size estimated from the above data. However, he points out in his paper [pp.131-136 of the NPA Conference Proceedings] that, even though this region has been under intense astrophysical observation since 1992, these observations have revealed “not a shred of evidence for any gravitational lensing.” The implication that necessarily follows is that the center of our galaxy does NOT contain any ‘black hole,’ otherwise the lensing would indeed occur.”

    Upon what philosophical basis do conventional theorists and advocates ignore such problems?

    Conventional thinkers will take down anybody who stands in the way of their preferred ideology. Halton Arp was one of the world’s most famous and respected astronomers when he presented observations which suggested that quasars are in fact associated with nearby energetic galaxies. He studied galaxies which were peculiar, and many of these galaxies are to this day named after him. He submitted his quasar paper for review to a black hole expert, Subrahmanyan Chandrasekhar, whose life work was threatened by this new observation.

    Chandrasekhar in turn scribbled, “This is beyond my comprehension”, onto the paper and refused to send it off to an impartial referee. Over time, since Arp was not generating research which was considered important compared with his astronomical peers, he would eventually lose his telescope time here in the United States. He has since moved to Europe where he can continue it.

    Most of these facts about Arp are by now well known to many, as they have been corroborated by people like Fred Hoyle and the Burbidges in “Universe — The Cosmology Quest”. One need only observe the YouTube or Google Video. Those who aren’t familiar with the details of the controversy might possibly ask themselves why it is so, and upon what philosophical basis they decide to ignore the controversy, and then propose that gravitational lensing can act as proof for anything at all. As for the public, they clearly expect that our theorists listen to our astronomers, and not dismiss their concerns when it suits the framework we taught them in college. Clearly, if Arp is right, then he has disproven the Big Bang theory. The road to truth in science is not a paved road, but you’d not know it talking to conventional theorists and advocates.

    The dismissive response that Arp and others have received is completely inappropriate given the weight of the controversy, and the details of the debate.

    Making matters worse, we can by now actually see the “black hole” at the center of our Milky Way galaxy in radio spectra, and it contains unexpected structure which conventional theorists never predicted. There is an image available here …

    http://www.holoscience.com/news.php?article=7qqsr17q

    The large majority of the imagery which people use to discuss NGC 7320 uses spectra which DO NOT SHOW THE CONNECTING BRIDGE. The bridge, however, can be observed plainly on Don Scott’s website at http://www.electric-cosmos.org/arp.htm, about halfway down the page.

    Excerpt …

    “In “Quasars, Redshifts, and Controversies” (p. 96-101) Halton Arp discusses the five interacting galaxies NGC 7317, 7318A, 7318B, 7319, and 7320 that constitute Stephan’s Quintet. The last one, NGC 7320, has a redshift value of 800 km/sec. The other four have redshifts of either 5700 km/sec or 6700 km/sec. Mainstream astronomers therefore claim those last four are about eight times farther away from us than NGC 7320. Therefore, they say, there cannot be any interaction between 7320 and the others.

    Arp states “The deepest 200 inch (Mt. Palomar) plates that I have been able to obtain clearly show a ‘tail’ coming out of the southeast end of NGC 7320.” He points out, “A tail like this from NGC 7320… must be an interaction tail – which could arise only from physical interaction with the adjacent high-redshift members of the Quintet.”

    He then states that at least one amateur has been able to see the tail but, “it is amazing that so many professionals have difficulty seeing it.” NASA routinely crops their images of Stephan’s Quintet to exclude the area where this tail would be seen.

    However, my good friend, amateur astronomer John Smith acquired a full image of the Quintet.

    The large, dark galaxy on the left is the low redshift NGC 7320. Then going counter-clockwise we have 7317, 7318A, 7318B, and 7319. At the top of the image is the small galaxy NGC 7320C. After some digital image processing (which only increased contrast), the result shown below was obtained.”

    If, after all of that, you still possess some great confidence that redshift can be explained with only one single velocity-based inference, then you might want to consider that you’ve permitted yourself to become biased. To those of us who remain open minded on this controversy, it is plain to see that mainstreamers are choosing which evidence to pay attention to, and playing games with spectra to make their point.

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