News EARTHS CORE HOTTER THAN THOUGHT !

[Mike Smith Cosmos]

Fresh news in about the Temperature of the core of the Earth.

 

link http://www.bbc.co.uk/news/science-environment-22297915

 

given to me by a University of the Third Age member U3A Geologists.

[arc]

http://www.geology.illinois.edu/people/xsong/Sites/papers/sun_song08_epsl.pdf
Geologists Xinlei Sun and Xiaodong Song at the University of Illinois have confirmed the discovery of Earth's inner, innermost core, and have created a three-dimensional model that describes the seismic anisotropy and texturing of iron crystals within the inner core. What they found was a distinct change in the inner core anisotropy, clearly marking the presence of an inner inner core with a diameter of about 1,180 kilometers, slightly less than half the diameter of the inner core. The layering of the core is interpreted as different texturing, or crystalline phase, of iron in the inner core, the researchers say.

"Our results suggest the outer inner core is composed of iron crystals of a single phase with different degrees of preferred alignment along Earth's spin axis," Sun said. "The inner inner core may be composed of a different phase of crystalline iron or have a different pattern of alignment."

 

Images and lower text Credit: Xinlei Sun and Xiaodong Song, University of Illinois at Urbana-Champaign/IRIS Consortium

Above left. Displays of the two-alignment model of inner core texturing, viewing from the North Pole (a) and along Meridians 40o and 220o (b), 100o and 280o ©, and 160o and 340o (d). The outer circle and the inner core circle (dotted) indicate the ICB (Inner core boundary) and the radius of 590 km, respectively. The dashed line in the western hemisphere of topmost inner core marks the region where anisotropy increases sharply with depth. (a) The circles and pluses indicate the fractions of polar alignment (f1) and equatorial alignment (f2) of the iron crystal's fast axis, respectively. The symbol size is proportional to the fraction. (b–d) The line segments indicate the fractions of polar and equatorial alignments.

 

I see similarities to the laminated iron sheets of transformer cores. In transformers each sheet is separated by a very thin non-conducting thermally insulating material. The lamination's are for suppressing Eddy currents, whereas cores that are solid iron are prone to development of Eddy currents. The electric currents induced in conducting materials within the cores, when exposed to changing magnetic field flux such as in AC transformers, are due to relative motion of the field source or due to variations of the field with time. This can cause a circulating current within the body of the core.

These circulating eddies of current have inductance and can therefore induce magnetic fields. These fields can cause repulsive, attractive, propulsion and drag effects. The stronger the applied magnetic field, or the greater the conductivity of the core, or the faster the magnetic field changes in time, then the greater the currents that are developed and the greater the fields produced. Eddy currents circulate within the core in a plane normal to the flux, and are responsible for resistive heating of the core material. The efficiency of the magnetic field is dependent on keeping Eddy currents to a minimum. Larger transformers rated for electricity distribution are generally more efficient, they control Eddy current losses through insulating the laminated iron plates, cooling through oil bath and cooling fins. They usually perform better than 98%.

 

Seismic anisotropy is an indicator of directional symmetry such as layers and even crystals that have detectable alignments. Significant seismic anisotropy has been detected in the Earth's inner core. Geological materials can exhibit electrical anisotropy; electrical conductivity in one direction is more efficient than another and can be measured and compared. This characteristic is used in the oil and gas industry to locate reserves; the instruments measure this conductivity/resistivity difference. The seismic anisotropy of the iron core is most likely congruent with electrical anisotropy and considering the possibility of enormous “crystalline iron” structuring it would be a significant contributor to the success of an efficient magnetic field generator in preventing eddy currents.

 

http://science.nasa.gov/science-news/science-at-nasa/2003/29dec_magneticfield/

A supercomputer model showing flow patterns in Earth's liquid core.

Dr. Gary A. Glatzmaier - Los Alamos National Laboratory - U.S. Department of Energy.
This article states that globally the magnetic field has weakened 10% since the 19th century. And according to Dr. Glatzmaier; "The field is increasing or decreasing all the time," "We know this from studies of the paleomagnetic record." According to the article; Earth's present-day magnetic field is, in fact, much stronger than normal. The dipole moment, a measure of the intensity of the magnetic field, is now 8 × 1022 amps × m2. That's twice the million-year average of 4× 1022 amps × m2.

 

This currently developing magnetic field generator model of Xinlei Sun and Xiaodong Song looks significantly more complex than the one in that film I watched back in 1974 in 7th grade science. arc

 

[michel123456]

I am confused. Is the inner core supposed to be solid or liquid?

[Mike Smith Cosmos]

I am confused. Is the inner core supposed to be solid or liquid?

michel

 

Arc is the one to answer this, but he's on the far side of the Globe, Think he gets up when we go to bed. you will have to wait until tonight for an answer.

 

However i was led to believe , that the inner core was solid and outer core liquid., because of the extreme pressure.

 

Mike

Edited May 18, 2013 by Mike Smith Cosmos

[Ophiolite]

Correct. Inner solid - outer molten. The inner core has been growing as it slowly cools. I imagine the new data interpretation on core - mantle temperature will modify our estimate of when solidification began.

[arc]

The inner core was always thought to be solid, but now with better resolution the inner core appears to be in two distinct zones of "seismic anisotropy and texturing of iron crystals within the inner core".

The inner core has previously been believed to be surrounded by the molten iron outer core that is associated to the field generator. This has not changed, this new discovery is concerning the inner core and a new inner-inner core. From what I can deduct it is not physically separate, i.e. rotating or moving independently. It looks to be involving the anisotrophy or preferred alignment of its interior structures to seismic waves. I have raised the question of whether the seismic anisotrophy could be aligned with or associated to an electrical anisotrophy.

 

The physical structuring "composed of iron crystals of a single phase with different degrees of preferred alignment along Earth's spin axis" is an interesting feature. Can it be associated or even modeled to the field generators performance as in suppression of eddy currents? The tremendous heat and pressure seen in the OP has contributed no-doubt to this 'different phase of crystalline iron" ​but could also the electric field and current involving the field generator be a contributor in its early development? Could the current high temperature be caused by eddy currents? This is a fascinating discovery in deep Earth science. arc

Edited May 18, 2013 by arc

[michel123456]

The inner core was always thought to be solid, but now with better resolution the inner core appears to be in two distinct zones of "seismic anisotropy and texturing of iron crystals within the inner core". [/size]

[/size]

The inner core has previously been believed to be surrounded by the molten iron outer core that is associated to the field generator. This has not changed, this new discovery is concerning the inner core and a new inner-inner core. From what I can deduct it is not physically separate, i.e. rotating or moving independently. It looks to be involving the anisotrophy or preferred alignment of its interior structures to seismic waves. I have raised the question of whether the seismic anisotrophy could be aligned with or associated to an electrical anisotrophy.

 

The physical structuring "composed of iron crystals of a single phase with different degrees of preferred alignment along Earth's spin axis" is an interesting feature. Can it be associated or even modeled to the field generators performance as in suppression of eddy currents? The tremendous heat and pressure seen in the OP has contributed no-doubt to this 'different phase of crystalline iron" ​but could also the electric field and current involving the field generator be a contributor in its early development? Could the current high temperature be caused by eddy currents? This is a fascinating discovery in deep Earth science. arc

If the inner core is solid, where does the tremendous pressure come from? A solid iron ball at the center of the Earth would have equal mass all around it, up down left right, and would theoretically feel no pressure at all.

I mean the fact that Newton showed that a body of mass X behaves as if all its mass was at its center does not mean that indeed all Earth's mass is at its center. Point 2 of the shell theorem states that at the center of the Earth, roughly there is no net gravitational force.

 

• 2. If the body is a spherically symmetric shell (i.e., a hollow ball), no net gravitational force is exerted by the shell on any object inside, regardless of the object's location within the shell.

Edited June 4, 2013 by michel123456

[arc]

If the inner core is solid, where does the tremendous pressure come from? A solid iron ball at the center of the Earth would have equal mass all around it, up down left right, and would theoretically feel no pressure at all.

I mean the fact that Newton showed that a body of mass X behaves as if all its mass was at its center does not mean that indeed all Earth's mass is at its center. Point 2 of the shell theorem states that at the center of the Earth, roughly there is no net gravitational force.

 

The mantle makes up 84% of the Earth's mass, add to that the molten outer core and you have with the crust the source of the pressure stated in the OP.

http://www.bbc.co.uk/news/science-environment-22297915

"Experiments outlined in Science used X-rays to probe tiny samples of iron at extraordinary pressures to examine how the iron crystals form and melt".

 

​ Are you suggesting an environment of 5000C with crystalline iron structuring in the center of an inner inner core has no pressure?

 

If you are correct than does this structure owe its characteristics to electrical current of the field generator? Or?

[Ophiolite]

Michel, you are confusing gravitational attraction with pressure.

[EdEarl]

It is confusing that gravitational attraction at the center of a sphere (the earth) is equal in all directions yet pressure is not zero. However, even a millimeter off center, gravitational attraction is not equal in all directions, which contributes to pressure not being zero.

[michel123456]

Michel, you are confusing gravitational attraction with pressure.

Yes I do.

 

What I mean is that if the core is solid, I can dig a tiny spherical hole at the center of the Earth (by some magical way), and this hole will remain void because the material all around is solid and cannot flow into the spherical hole.

Edited June 5, 2013 by michel123456

[zapatos]

What I mean is that if the core is solid, I can dig a tiny spherical hole at the center of the Earth (by some magical way), and this hole will remain void because the material all around is solid and cannot flow into the spherical hole.

If I am tightly squeezing a can of Coke, and I suddenly open the can to remove the soda from inside, the ensuing void inside will not remain, even though the material all around is solid. Wouldn't the same happen in the center of the earth?

[Amaton]

What I mean is that if the core is solid, I can dig a tiny spherical hole at the center of the Earth (by some magical way), and this hole will remain void because the material all around is solid and cannot flow into the spherical hole.

 

Simply "blanking" a spherical volume within a solid iron ball in normal conditions wouldn't change much given the sturdy outer structure. Earth's solid core, on the other hand, is still pretty hot and under extreme pressure. That immense pressure might collapse the iron-nickel mass into it from all directions, thus shrinking or completely eliminating the blank.

 

EDIT: This is still a speculatory answer, though, given by analogy. I'd wait to see what an expert might say on it since physical changes at such extreme conditions are less likely to follow intuition. Also, dense iron-nickel solid isn't exactly as "malleable" in shape as one might think, due in part to whatever kind of molecular structure it might hold.

Edited June 5, 2013 by Amaton

[Enthalpy]

...if the core is solid, I can dig a tiny spherical hole at the center of the Earth [...] and this hole will remain void...

This time I shall disagree, exceptionally. Solids get deformable once their yield strength is exceeded, which is by very far the case deep in Earth, even if the temperature were low.

 

At just 1000km depth, the isostatic pressure is already ~5GPa, exceeding the hardest tool steel. A hole there would make the stress no more isotropic (zero stress perpendicular to the hole's surface) and let collapse the hole.

 

It's the same yield strength that lets an ammunition round deform nearly without resistance upon impact with a armour. Experts compute such a hypervelocity impact using zero yield strength, as if the metal were a liquid, because the impact stress overwhelms any strength.

[michel123456]

This time I shall disagree, exceptionally. Solids get deformable once their yield strength is exceeded, which is by very far the case deep in Earth, even if the temperature were low.

 

At just 1000km depth, the isostatic pressure is already ~5GPa, exceeding the hardest tool steel. A hole there would make the stress no more isotropic (zero stress perpendicular to the hole's surface) and let collapse the hole.

 

It's the same yield strength that lets an ammunition round deform nearly without resistance upon impact with a armour. Experts compute such a hypervelocity impact using zero yield strength, as if the metal were a liquid, because the impact stress overwhelms any strength.

So the core is a kind of flowing solid ?

[Enthalpy]

Already the crust breaks of flows in response to limited pressure differences This tells why mountains are only 9km high, as compared with 6400km Earth radius.

 

The core is hot enough for iron and nickel to be liquid. But currently fashionable theories want the inner core to be a solid, as pressure suffices there to create an iron-nickel crystal with a higher fusion temperature.

 

In any case, the hydrostatic pressure exceeds the materials' yield strength so they flow - much more so because heat reduces the yield strength, and because over geological time, "flow" is more a very slow creep, against which hot materials have very little resistance.

 

So what shall "solid" mean? It's "measured" in the laboratory over a short time and essentially no shear stress. As well, some shear resistance over the duration of earthquakes waves would fit observation well - this is compatible with creep over geological times.

[arc]

It is an easy mistake. Similarly, I have caught myself several times associating an increasing depth and pressure with an increase in gravity. Gravity is highest at the surface and decreases with depth.

 

If one such as I is not careful, it is carried to depth with pressure and multiplied. arc

Edited June 8, 2013 by arc