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Paul. a thought occurred to me while dog walking. I wonder if your idea that the core rotates in the opposite direction came from the fact that the differential rotational rate causes the axis of rotation of the inner core to precess eastward. Could that be right?


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Bill, I did some checking after I saw that claim by Paul. He is right. If you do a search for Earth core rotation you can find a number of sources for the information. One of them is Why Earth's Inner and Outer Cores Rotate in Opposite Directions. What I am not sure about is the rates of rotation.

On Discovery I found this. Earth's Rotating Inner Core Shifts Its Speed According to this one the inner core rotates in approximately every 750 to 1,440 years.

The Daily Mail has an article Earth's inner core spins in an eastward direction - the opposite to the outer core . In this one it doesn't say how fast the outer core spins except to say "Meanwhile the outer core, made up of mainly molten iron, spins westwards at a slower pace". So the outer core takes even longer than to inner core to make a revolution.

I don't think that is going to provide anything to help Paul's hypothesis.

Bill gill


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this article is from Columbia University
Dr. Song and Dr. Richards

http://www.columbia.edu/cu/record/archives/vol22/vol22_iss1/Core_Spin.html

Quote:
The inner core rotates in the same direction as the Earth and slightly faster, completing its once-a-day rotation about two-thirds of a second faster than the entire Earth. Over the past 100 years that extra speed has gained the core a quarter-turn on the planet as a whole, the scientists found. Such motion is remarkably fast for geological movements -- some 100,000 times faster than the drift of continents, they noted. The scientists made their finding by measuring changes in the speed of earthquake-generated seismic waves that pass through the inner core.


and its 400 years per revolution.

Quote:
Dr. Song and Dr. Richards calculated that over a year, the inner core rotates about one longitudinal degree more than the Earth's mantle and crust. The inner core makes a complete revolution inside the Earth in about 400 years.


I certainly hope you guys didnt expect it to spin much faster
than that.

with that apx 5,000 C and 140gpa pressure at the outer core
its a wonder the outer core can spin at all , much less in an opposite direction from the mantle and crust above it
and the inner core below it.

its fascinating stuff.

but the earth is a awesomely large dynamo down there.
and thats why there are different speeds and directions of
the different layers of earth.

I can certainly understand how a faster moving crust would
stir up a lot of extra heat down there , sorry if you guys
cant see it that way.

any extra heat down there eventually makes its way up here.

it has no where else to go...




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400 years per revolution?

So in 400 years, the planet rotates, or revolves, (let's say) 146,100 times.
That means, over that same time, the inner core would rotate 146,101 times, right?

I'm unsure of the other rotation comments, such as retrograde motion, but the idea that they are talking about the axis of rotation ...and perhaps precession, sounds more likely.

I wonder what this might mean for mantle plumes....

- wink


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Quote:
The inner core rotates in the same direction as the Earth and slightly faster, completing its once-a-day rotation about two-thirds of a second faster than the entire Earth. Over the past 100 years that extra speed has gained the core a quarter-turn on the planet as a whole, the scientists found.


It seems that these stats are a bit out of date, and about a million times too fast.

http://phys.org/news/2011-02-earth-core-rotating-faster-rest.html

The outer core is liquid, so its movement relative to the inner core and mantle is likely to be “chaotic” if they are rotating at different rates. It is difficult to imagine a mechanism that would start and maintain the movement of a liquid in a direction opposite to that of the solids enclosing it.

You can find all kinds of statements and scientific “facts” on line. Try googling something like “Do photons experience time”!

Here’s an example:

http://www.askamathematician.com/2011/07/q-does-light-experience-time/


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Originally Posted By: Paul
I can certainly understand how a faster moving crust would stir up a lot of extra heat down there , sorry if you guys
cant see it that way.


I'm not sure what we are supposed to see. If the crust were moving faster than the upper mantle, I can see that that would generate a lot of heat, but not only is there no evidence that there is differential motion along the Moho; there is good evidence that tectonic plates are composed of crust and upper mantle, and that movement occurs at the LVZ, deeper in the mantle.


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Quote:
I wonder what this might mean for mantle plumes....


It will mean a lot less if the latest figures are correct.

BTW; are you a plume supporter?


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well , I guess it all boils down to which article is found first, LOL.

I have a definite problem with the article you posted about
Cambridge U.

Quote:
The inner core grows very slowly over time as material from the fluid outer core solidifies onto its surface. During this process, an east-west hemispherical difference in velocity is frozen into the structure of the inner core.


its obvious that solid FE which comprises the inner core
is heavier than the composition of the FE and S above the inner core.

its also obvious that when pure FE is separated out of the FE and S of the outer core and the pure FE bonds with the inner core there are things that happen.

1) there would be a layer just above the inner core consisting mostly of pure sulfur.

2) the viscosity of the pure sulfur when heated increases unlike other substances whos viscosity decreases.
and I haven't yet to read any evidence in your article that
discusses this variation in viscosity concerning the sulfur
that would be deposited from the FE and S in the outer core.
given that the pressures would increase the melting and boiling temperatures and other properties.

3) the momentum of the inner core would decrease and likewise
the momentum of the outer core would increase.
this would point to the inner core slowing down during the process , not speeding up.

Quote:
The faster rotation rates are incompatible with the observed hemispheres in the inner core because it would not allow enough time for the differences to freeze into the structure


Im curious if the differences above and the what they found that consistently shifted east with depth was nothing more than layers of sulfur.

the sulfur could have a viscosity that is so strong that it
could be being confused with the upper 90 km of the inner core , also the density of the sulfur could have a great
potential for confusion.

the only evidence we have is through the use of seismic waves
and a layer of sulfur might just slow down a seismic wave.

we have observed huge boulders floating on fast moving water here on the surface of the earth.

with the increased pressures and viscosities of sulfur down there velocities are not really that important for such a thing to happen.

so the FE and S could be floating on top of the pure sulfur.

the article about the hypothesis and its proposed inner core speed and the reasons it claims that the previous speed is wrong and the evidence given is too questionable for
me to accept.








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Paul, you raise some interesting issues in your last post, I'm not ignoring it; just a bit short of time.


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Originally Posted By: Bill S.
Quote:
I wonder what this might mean for mantle plumes....


It will mean a lot less if the latest figures are correct.

BTW; are you a plume supporter?

I only heard some news (plus saw some awesome "picture") of latest data that sounded fairly normal and well accepted. Is there some disagreement or alternative explanations?

I think most significant is that Continents are original, multi billions-year-old crust, and yet the oldest seafloor crust is only a fifth of one billion years old.

I've been trying to learn about the evolution of soils, and sediments and sedimentary processes play a big role. Big understatement, I'm sure, but new paradigms point to both changing life and changing climate has determined evolution of different soils ...as well as the rocks and clays that many buried, weathered, and/or petrified soils turn into. ...or words to that effect.

The weight of those sedimented layers, especially in various areas on the generally bowl-shaped Continents, has me wondering about growth of continental "roots" and if material exchanges with the mantle or those "young" subducted plates.

Aside: do you think a radically different distribution of glacial ice sheets could alter tilt and wobble of the planet?

~ wink


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Originally Posted By: Paul
the momentum of the inner core would decrease and likewise
the momentum of the outer core would increase.
this would point to the inner core slowing down during the process , not speeding up.


Quote:
The magnetic field pushes eastwards on the inner core, causing it to spin faster than the Earth, but it also pushes in the opposite direction in the liquid outer core, which creates a westward motion.


The momentum of the inner core would decrease only if the deposition had a greater influence than the pushing effect, which is unlikely. Given that there is a pushing effect, wouldn’t the increase in mass involve an increase in momentum? P=mv, so if v is maintained, and m increases, p increases.

Would the opposite not apply to the outer core?

In your model, which I am not disputing at this point, the inner core and outer core rotate in opposite directions. Both chemical reactions and frictional drag operate at the inner/outer core boundary and the outer core/mantle boundary. Wouldn’t this tend to slow the rotation of the outer core, and promote turbulence; rather than increase it, as you suggest?


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As with many things, it is possible to find different chemical formulae in different references for the deep Earth. From my recollection of Open University days, and more recent reading, I think that seismic studies indicate that the inner core is composed of 90+ % Fe/Ni, with some lighter minerals.
The outer core is believed also to be mainly Fe/Ni with possible some S. What it comes down to is that one has to evaluate information as best one can, and wait for the next discovery to add further confusion. smile

Discoveries made a few years ago suggest that the lighter elements in the inner core might have migrated to the top.

http://www.livescience.com/10324-earth-core-layer-scientists-claim.html


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Quote:
The magnetic field pushes eastwards on the inner core, causing it to spin faster than the Earth, but it also pushes in the opposite direction in the liquid outer core, which creates a westward motion.


I sure would like to see the model that would show a magnetic field that could do that.

from what I know about magnetic fields you need motion of the field in order to push anything in a direction.

and the direction of motion of the inner core is eastward.
an eastward motion cannot push westward.

how do they explain that away?

lets try using the shell of the inner core as if the magnetic field were shaped like a big donut.

even still the direction is eastward because the core spins eastward.

you would need 2 separate magnetic fields.
could there be 2 separate magnetic fields?

I suppose you could have 2 separate magnetic fields ,
because you do have 2 cores that are spinning.
it could be like a small magnet inside a larger magnet.

I really want to see that model.

I would like for us to clear the above up first if we can.

Quote:
wouldn’t the increase in mass involve an increase in momentum? P=mv


if there were an additional force added for rotation as the additional mass is added to the rotation then yes, the momentum would increase.

what we have here is a big ball of iorn that already has a amount of momentum which is P=mv.

----------
in order to add velocity to the inner core
you would need to supply enough force to accelerate the entire
mass of the inner core to the desired velocity!!!

----------

momentum = the mass of an object times its velocity.

without adding velocity to the object the momentum
of the object will decrease.

it would be extremely hard to get me to believe that
when some iorn is deposited onto the surface of the inner core
there is somehow a corresponding added force added to rotate the inner core.

perhaps at this point is where QM and relativity could solve the dilema.

the added velocity just pops in from one of the many parallel universes or what ever is popular that day.





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Quote:
I sure would like to see the model that would show a magnetic field that could do that


It wasn't my link that that came from.

Just like to show that I read other folk's links. smile


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Even if they are from the Mail! laugh


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Even if they are from the Mail! wink

or one of these !

http://www.sciencedaily.com/releases/2013/09/130916162005.htm

http://www.scienceworldreport.com/articl...ns-eastward.htm


http://www.astrobio.net/pressrelease/5699/the-dynamics-of-earths-core

these days is pays to think about what you read , a lot of it
just gets copied from one web site to the next without the application of thought.











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So far I've had time only for a glance at the first of your links.

It seems to talk of S waves propagating through the core. Unless the laws of physics have changed in the last 30 years, S waves don't propagate through liquids.

I seem to recall that S waves reaching the outer core can somehow propagate as modified P waves, then change back into S waves when they reach the inner core, but I don't remember the details, and don't have the time to look it up.

Does anyone else feel that what is being interpreted as westward motion of the outer core might mean only that the inner core and the mantle/crust are rotating eastward faster than the outer core?


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Originally Posted By: Bill S.

Does anyone else feel that what is being interpreted as westward motion of the outer core might mean only that the inner core and the mantle/crust are rotating eastward faster than the outer core?



I do. The inner core is rotating about 2/3 of a second per day faster than the mantle/crust (Core Spins Faster Than Earth). So the fact that the outer core is 'rotating in the opposite direction' Doesn't mean that it is really going the other way around. In fact since it seems to be rotating more slowly in the reverse direction (that's from one of the links I threw in up above) then it isn't exactly like driving the wrong way down a freeway at 100 mph. The reversal of direction is relative to the inner core and the mantle/crust. With respect to the stars it is still rotating the same way.

Bill Gill


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There’s a lot of misinformation out there. Much of it is generated by the media who are more interested in a story than in fact; but some obviously comes from enthusiastic researchers who understandably want to push their ideas to the fore.

Whatever one may believe about humans having walked on the moon, or about our machines being on other planets; one thing is certain: we have never visited the mantle, much less the core.

We know little about the mantle, and even less about the core. My belief is that the best we can do is to evaluate the information available in the light of physics and common sense, and see where it leads.

I may not have accepted Paul’s argument at the start of this discussion; I may still not accept it at the end, but I think the proposal and discussion of non-mainstream ideas is always likely to be of value.

I bet that’s no surprise to anyone on SAGG. smile


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Let's have a go at clearing this one.

Quote:
….if there were an additional force added for rotation as the additional mass is added to the rotation then yes, the momentum would increase.


If p=mv, and m is increased, v could decrease by the appropriate amount and p could remain unchanged. Even without a mysterious force appearing from somewhere, p would not necessarily decrease as mass was added.

The point I was making included the statement, in Bill’s link, that the magnetic field did some pushing. If that were the case p could actually increase as m increased.

There is an added complication in that it is possible that melting of the upper layer of the inner core is also occurring. I have yet to find any reference as to how that fits in with the deposition of material from the outer core onto the inner.


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