What is the mechanism behind the heating of the Earth's core?

[Smart Guy]

Pretty good

If you told me that the Earth was hollow I would say okay, Back that up with facts.
Theories should be proven. The statements I made were all facts.To disprove my theory would require facts of your own. The Cores heat is not generated but stored in the mantle. The illustration you showed me had a core1 and core 2 the interactions between the two create only one core. No proof. Well my proof comes from the fact that since the mantle is the only true liquid and "the cores middle" aka... inner core is solid. The mantle has to store heat, because like you said the pressure at the Earth's core is so great there is very little molecule movement unlike the mantle. And we all know heat is generated by movement of molecules to a certain point.


What do you think...
And be nice

 

[Chemicalsuperfreak]

Originally posted by Smart Guy
If you told me that the Earth was hollow I would say okay, Back that up with facts.
Theories should be proven. The statements I made were all facts.To disprove my theory would require facts of your own. The Cores heat is not generated but stored in the mantle. The illustration you showed me had a core1 and core 2 the interactions between the two create only one core. No proof. Well my proof comes from the fact that since the mantle is the only true liquid and "the cores middle" aka... inner core is solid. The mantle has to store heat, because like you said the pressure at the Earth's core is so great there is very little molecule movement unlike the mantle. And we all know heat is generated by movement of molecules to a certain point.


What do you think...
And be nice

Heat isn't generated by the movement of molecules. Heat IS the movement of moleculars, or actually the transfer of energy from one group of moving molecules to a slower group of moving molecules. But like I've stated above, most of the interior's heat is due to radioactive decay. If there wasn't this source of heat, the interior would have frozen billions of year ago.

 

[Nommos Prime (Dogon)]

Vaccum Heart Theory

What do you guys think of this theory regarding the heating of the Earth's core? (Vacuum heart theory). The Russians have done some great work on it (the paper loses a bit in it's translation).

http://www.geocities.com/Area51/Nebula/3735/engearth.html

 

[Smart Guy]

I love intellegent conversation

Sorry for the mistake. Heat IS the movement of molecules. Also a very good argument for Radioactive Decay. Maybe there is not just one source of heat, I believe that the amount of heat transferred down by plate movement ie friction between the two would be sufficient enough to compensate for any heat loss even over billions of years. That heat is then transferred down and stored in the mantle the rest is realeased.

 

[sage]

mantle is NOT LIQUID. one can infer the state of the Earth rocks by the velocity of the seismic waves. mantle in fact turns out to be a kind of solid which can flow(or semisolid). outer core is fluid while inner core is solid. and yes the crust is a poor heat conducter. another thing. heat is THE GENERATOR OF ALL TECTONIC MOVEMENTS ON EARTH. don't you think if the heat inside Earth was only residual heat and hence always decreasing with time, the Earth would have been a much quieter place? in fact more heat is being generated than can be released, leading to heat buildup, local melting, convection current, mantle plumes, plate tectonics and what not. thing to see is whether radioactive decay can account for all this heat, scientists seem to think so and we should find out what they are saying before jumping at other alternatives.

 

[Smart Guy]

I had you .

Originally posted by sage
mantle is NOT LIQUID. one can infer the state of the Earth rocks by the velocity of the seismic waves. mantle in fact turns out to be a kind of solid which can flow(or semisolid). outer core is fluid while inner core is solid. and yes the crust is a poor heat conducter. another thing. heat is THE GENERATOR OF ALL TECTONIC MOVEMENTS ON EARTH. don't you think if the heat inside Earth was only residual heat and hence always decreasing with time, the Earth would have been a much quieter place? in fact more heat is being generated than can be released, leading to heat buildup, local melting, convection current, mantle plumes, plate tectonics and what not. thing to see is whether radioactive decay can account for all this heat, scientists seem to think so and we should find out what they are saying before jumping at other alternatives.

I had you, but I lost my whole reply. 4000 characters down the drain.
Well thought out and articulated. I was just getting started good too. To sum it up I said the Mantle was kept at a constant temp. Heated by friction and cooled by cracks in the Earth's crust. I mentioned the amount of seismic activity per day. So on and So fourth


Dont reply please I am disgusted. Instead let do another topic.[b(]

 

[Mr. Robin Parsons]

Originally posted by Smart Guy
If you told me that the Earth was hollow I would say okay, Back that up with facts.
Theories should be proven. The statements I made were all facts.To disprove my theory would require facts of your own. The Cores heat is not generated but stored in the mantle. The illustration you showed me had a core1 and core 2 the interactions between the two create only one core. No proof. Well my proof comes from the fact that since the mantle is the only true liquid and "the cores middle" aka... inner core is solid. The mantle has to store heat, because like you said the pressure at the Earth's core is so great there is very little molecule movement unlike the mantle. And we all know heat is generated by movement of molecules to a certain point.
What do you think...
And be nice

"Heat storage" is an unknown phenomenon in current Science, laws of thermodynamics prohibits it, all heat is radiant...

 

[FZ+]

But that heat does not radiate away instantly, and it dissipates away differently for different objects. I think heat storage here is used to mean a substance that radiates very slowly, so that the heat is temporarily delayed within the mantle.

 

[Mr. Robin Parsons]

Originally posted by FZ+
But that heat does not radiate away instantly, and it dissipates away differently for different objects. I think heat storage here is used to mean a substance that radiates very slowly, so that the heat is temporarily delayed within the mantle.

Nice thought, problem though with the mantle, as Rock is NOT a good insulator, actually quite a poor one as most able insulators work on the basis of 'trapping' heat in gasses, as to slow transfer rates. Water is a much better insulator then mantle rock, but its coating is superficial, though still effective.

There is a tremendous amount of pressure at the center of the Earth, perhaps the minute 'Working(s)' of the plastic(s) (rock/metals/minerals) at those points, generate more heating, through pressurization, (Not pressure) then is currently thought.

Perhaps it is that minutia that actually works, consistently over time, via the stresses and pulls of the "spacial environment" (Sun moon, other planets, satellites) that is generating a quotient of that heating effect.

 

[Mr. Robin Parsons]

Perhaps you should understand that I am not arguing against heat storage, (by mantle) just that the amount of heat required, tells us clearly that, there must be other sources for that heating, as the generation of heat must be ongoing to have lasted this 4.5 billion years that the planet has had to cool off...

The Apollo astronauts found the Moon to be emitting/generating Heat, maybe the rest of the panetary bodies do so to, just relitavized to their respective spacializations.

The manner of the storage is probably a little more complex then just the idea of 'dissipation alone' as agent/operator of the storage mechanism(?).

 

[Andre]

I think I said it before but my guess is that one of the possible heat sources is friction, especially in the inner /outer core boundary and the core mantle boundary, where external forces acting upon earth, especially the precession of the equinoxes will generate accellerations, hence movement and hence drag or resistance.

It has been argued that Earth magnetic field is tied to that precession reactions as there has been a study long ago that suggested that there was some correlation between precession rates and magnetic field of the different planets. The paleomagnetic excursions, that we see about every 50-100,000 years may indicate that some severe things are going on over there, chaotic eddies perhaps that create a lot of drag/heat periodically. This all slows down Earth. So the Earths turning energy may be converted to heat.

Just thinking.

 

[Mr. Robin Parsons]

Gotta remember that there is almost 4 M bars of pressure at the center, that is a lot of pressure/pressurization that has yet to be explained as to how that is brought into being...and pressurizational processes generate heat/ing...

As for the existence of "boundary levels", how the heck does that happen, and why?? Mantle/outer core, outer core/core, core/innercore and the idea that 'rock' acts like a 'plastic' is just so neat!

 

[Nereid]

Originally posted by Andre
I think I said it before but my guess is that one of the possible heat sources is friction, especially in the inner /outer core boundary and the core mantle boundary, where external forces acting upon earth, especially the precession of the equinoxes will generate accellerations, hence movement and hence drag or resistance.

It has been argued that Earth magnetic field is tied to that precession reactions as there has been a study long ago that suggested that there was some correlation between precession rates and magnetic field of the different planets. The paleomagnetic excursions, that we see about every 50-100,000 years may indicate that some severe things are going on over there, chaotic eddies perhaps that create a lot of drag/heat periodically. This all slows down Earth. So the Earths turning energy may be converted to heat.

Just thinking.

Hey Andre, how about taking out an old envelope and doing some OOM (order of magnitude) calculations on the back of it? You know, surface area of your favourite boundary, coefficient of friction, distance moved, energy generated, time period, ... you could quickly determine how realistic your thinking is!

 

[carl fischbach]

tempurature difference due to gravity

I've found an interesting web page that virtually proves that a column of gas under gravity is warmer at the bottom than the top, and can be
viewed at www.firstgravitymachine.com/index.phtml[/URL] this explains jupiter's core temperature of 20,000 K and a significantly cooler surface temperature although it is the overal cooling
of the planet and work done by gravitational contraction of the planet that is responsible
for it's excess heat. It is this gavitational
heating effect that explains the temperature
differences at various altitudes on earth. Why not take it one step further and apply it to the Earth itself.

 

[Andre]

Nereid,
I still think that almost nothing times almost infinity can still add up to something.

I think we can assume that the sun-moon gravity force that generates the precession of the Equinoxes, only works on the equatorial bulge and hence the lithosphere/mantle. Somehow this movement has to be transmitted to the solid inner core, to keep aligned. The precession cycle it is completed in a mere 26,000 years, the spin axis of the solid inner core has to be dragged along over 2 x 23 degrees in only 13,000 years. Now this is only a infinitesinal small rate per second but the turning momentum of the inner core is of a tremendous value and it increases very rapidly, to the fifth power of the radius if I'm right when the core cools down and grows.

I need a big envellope.

 

[Mr. Robin Parsons]

If you go to any gasoline station you will find the gas pump 'tagged' with a "volume adjusted" labelling. Here, at this latitude, it reads "Volume temperature compensated to 15° C", this is due to the simple fact that the planet is 'heated' proven by its generation of a consistant temperature, just under the surface, (About 8' down here) of 15° C, over the entire YEAR! (without an great fluctuations)

There is a gradient of temperature as you press down into the earth, it is measurable in feet/meters (whatever you like) but it is a consistant rise in temperature over distance in. It is proven by what has been shown on television, from the deep mines in Africa, about a mile and a half down, a thermometer pressed against the mine's walls showed a temperature of 56° C (Hot enough for ya?)

That gravity is involved in the heating was once discussed in "Astro and Cosmo" in the thread "Proof of the Cause of Gravity", by myself, et al.

 

[Andre]

Fully correct Mr Robin,

However there is also an idea that the heat in the crust could be radiogenic:

http://www.vanderbilt.edu/radsafe/9512/msg00248.html

3. More radiogenic heat is produced from the granitic continental crust, which contains higher concentrations of the radioactive elements and is thicker than the basaltic oceanic crust.
(...)
6. Some scientists believe that natural nuclear reactors such as the one at Oklo in Gabon, Africa (Draganic and others, 1990) were much more common during early Earth history. These reactors may have raised radioactive levels at many places on the earth. During early Earth history fissionable U-235 made up about 25% of the uranium. Today U-235 makes up only about 3/4 of one percent of uranium due to its shorter half-lifel (0.7 billion years)

Nereid
I'd appreciate you're opinion on this one:

http://www.randi.org/vbulletin/showthread.php?s=&threadid=30992

 

[Nereid]

"something"?

Andre wrote: I still think that almost nothing times almost infinity can still add up to something.

That's why an OOM calculation is a good place to start! You could even approach it from the other direction - since we know the rate of heat loss from the inner Earth (i.e. not counting any latent effects of absorbed solar radiation), your idea has to come up with a number that's between ~0.01 and 100 times this value (at the OOM stage, it's OK to work with a couple of powers of ten). You say you know the timescale for the effect you propose, you know the mass of the Earth (and its components), and you can work out the forces with only a very small envelope. That leaves only one unknown (maybe two). At this level of accuracy, does the answer seem realistic?

 

[Mr. Robin Parsons]

Originally posted by Andre
(SNIP) However there is also an idea that the heat in the crust could be radiogenic: (SNoP)

Yes!, I agreed that there is radioactive heating, just that it didn't seem that that was the 'only method' of heating that was involved in the "whole process of heating". Heck "working a plastic" will cause the 'plastic' to heat...gravity is involved as well though, just it isn't 'current theory'.

What is the 'Randi' connection, don't get it?

 

[Andre]

What is the 'Randi' connection, don't get it?

Well I posted that thread about the "death" hypothesis of Venus in the skeptic lions den over there either to fortify it or have it falsified.

There is a lot about general planets heat in that hypothesis. Hence the connection.

Have tried the thread here also but there was little interest at that moment. Like me to try again?

 

[Mr. Robin Parsons]

Originally posted by Andre
Well I posted that thread about the "death" hypothesis of Venus in the skeptic lions den over there either to fortify it or have it falsified.
There is a lot about general planets heat in that hypothesis. Hence the connection.
Have tried the thread here also but there was little interest at that moment. Like me to try again?

Not particularily... the re-facing of the planet, 500K years back, is not an indication of its death, merely an event that we have yet to determine the origin thereof.

Venus is apparenlty devoid of any real amounts of water, contained within the rock, there, unlike here, where the rock (apparently) contains significant amounts of water, water moderates temperatures really, really well. (It's the benchmark of "Specific Heat")

As I have stated above, gravity is involved in the heating, just that it is not a responce you will find in current theory, not to the best of my knowledge....

 

[Andre]

the re-facing of the planet, 500K years back, is not an indication of its death, merely an event that we have yet to determine the origin thereof.

Well that's exactly what I propose. The big precession brake halted the planet and heated it intensely, causing the surface to melt partially or as a whole.

Venus is apparently devoid of any real amounts of water, contained within the rock, there,

Exactly, indicating that the temperatures rose over 1100 degrees celsius causing limestone (CaCO3) to reduce to CaO and CO2, the latter caused the dense atmosphere (CO2). The former, CaO is abundant in the lithosphere (7%).

The envellope is almost ready.

 

[Mr. Robin Parsons]

How it heated?? a "precession brake" you say, I'm not sure if it's that, there are other venues and mannerisms of the universe's operation that are, as yet, undiscovered, especially in the 'heat'ing departement. (I suspect)

Could have been a type of 'fissile', of 'fusile', 'burp' for all anyone currently knows of the interior operations of planetary bodies.

Heated? yes! it was, (seems to have been) but the 'how' is, as yet I suspect, unsolved.

 

[Andre]

Well, again Mr Robin, I think I solved that problem. This is it:
This is Venus:

The atmosphere consists mainly of carbon dioxide (the same gas that produces fizzy sodas), droplets of sulfuric acid, and virtually no water vapor - not a great place for people or plants! In addition, the thick atmosphere allows the Sun's heat in but does not allow it to escape, resulting in surface temperatures over 450 °C, hotter than the surface of the planet Mercury, which is closest to the Sun. The high density of the atmosphere results in a surface pressure 90 times that of Earth, which is why probes that have landed on Venus have only survived several hours before being crushed by the incredible pressure. In the upper layers, the clouds move faster than hurricane- force winds on Earth.

Venus sluggishly rotates on its axis once every 243 Earth days, while it orbits the Sun every 225 days - its day is longer than its year! Besides that, Venus rotates retrograde, or "backwards," spinning in the opposite direction of its orbit around the Sun. From its surface, the Sun would seem to rise in the west and set in the east.

Earth and Venus are similar in density and chemical compositions, and both have relatively young surfaces, with Venus appearing to have been completely resurfaced 300 to 500 million years ago.

The surface of Venus is covered by about 20 percent lowland plains, 70 percent rolling uplands, and 10 percent highlands. Volcanism, impacts, and deformation of the crust have shaped the surface. No direct evidence of currently active volcanoes has been found,..

We can tie all those boldface features to a single event, the big precession brake.

How Venus died

We start assuming that Venus was a normal planet just like Earth. There are many differences however, for instance, Venus seems not to have a liquid outer core today. It is unknown if it has had one before but using the analogy with Earth we assume that it did. So let's first look at a hypothetical normal planet with mostly Earth-like features assuming Earth is the standard, not Venus.

The outer core of such a standard planet can be fluid mass, due to the high temperature. However, the inner core of a planet is solid again due to the immense pressure it is subjected to, in spite of the temperatures. In the core is a equilibrium between those two opposing tendencies.

It is spinning around the sun and spinning around its axis in a much similar way with same order of magnitude parameters. By spinning the planet behaves as a gyroscope or spinning top and can be subject to changes in spin axis direction by precession.

Just like Earth this juvenile planet Venus also has precession of the equinoxes due to a certain obliquity and the sun and (perhaps a possible moon) having a differential gravity pull on the equatorial bulge.
see also
http://www.copernican-series.com/precession.html
http://cse.ssl.berkeley.edu/lessons...th_precess.html
on precession

Other planets are also in precession, there is no moon required for that, just gravity, generally here is the math behind the idea:
http://scienceworld.wolfram.com/phy...Precession.html

Now we assume the planet to be a single unit, a single gyroscope with a single mechanical reaction. But it isn’t. The mantle and the solid inner core could be pretty much independent gyroscopes, with different characteristix, tied together by a fluid outer core.

I think we can assume from the mechanism that the sun-moon gravity force that generates the precession, is basically working on the equatorial bulge and hence on the lithosphere/mantle.

Now does the precession also work on the solid inner core? It may have an equatorial bulge. However, due to non-linear relationships, the precession logic of the inner core must differ from the mantle-crust precession. (see also Correia et al part I, 3.2) Hence the inner core has a tendency to change its spin axis in relation to the mantle crust due to dissimilar precession tendencies.

Note that the precession itself actually rotates spinning axis and hence it is changing the vector direction of the angular momentum. External forces, like gravity between celestial bodies transfer momentum this way.

The fluid outer core couples the motions of both solid systems. To keep spin axis aligned, the fluid outer core has to transmit these precession movements from mantle to the solid inner core somehow, like a torque converter in a transmission gear of a car. It contains some natural mechanic and perhaps magnetic stabilising properties to correct for that drifting motion, as we see no problems on Earth today, but its stabilising capacity is limited and can only physically control a limited angular momentum.

The size of the solid inner core is a function of amount of heat and pressure. The high temperature leads to liquefying and the high pressure leads to solidifying. But as the planet is cooling the amount of heat is decreasing and hence the solid inner core is expanding while the outer core is shrinking. The turning momentum of the inner core is of a tremendous value and the inner core grows, it’s increasing its angular momentum rapidly, to the fifth power of the radius, if I'm right

As the core grows its angular momentum increases beyond stabilization, eventually its precession drift will break alignment of the spinning axis. This causes heavy turbulence in the fluid outer core affecting the motion of the mantle and the inner core and it also generates drag and heat. The heat may have partially liquefied the solid inner core, decreasing it’s angular momentum and reversing the whole process back to stability. When the precesssion cycle is completed, realigment and stabilisation can occur again. However cooling continued and the inner core precession break out would occur again and this process may repeat over and over again until the spinning stops eventually.

Note that the growing misalignment of the spin axis causes the vector sum of the angular momentums of the mantle and the core to decrease, whilst angular momentum is transferred via external gravity forces to the infering celetial body during the precession. The actual transfer of momentum becomes visible only after the realignment, when a precession cycle is complete. There is no momentum loss, just momentum transfer over billions of years

The generated heat will be transmitted throughtout the whole planet, facilitated by the increased heat transport capability of the turbulent fluid outer core, causing the planet to melt partially or as a whole. Due to the heat convection the planets surface would be renewed by convection of material. As the heat would exceed general melting temperature it would also enough to cause limestone to decompose into calcium oxide and carbon dioxide that happens around 1100 degrees celsius. The carbon dioxide would escape from the lithosphere via the characteristic dome volcanoes (pancakes) to form a dense atmosphere. After the precession induced rotation stop, a very hot planet would remain with a dense carbon dioxide atmosphere. It would cool only very slowly as the carbon dioxide works as an isolation blanket and also retains solar heat due to greenhouse effect.

Due to interaction of the dense atmosphere with the sun stable equilibrium will emerge eventually.
Correia and Laskar (A Correia and J Laskar 2001 Nature 411 767) found that the rotation can only end in four possible spin states. Such planets can have either retrograde or 'prograde' rotation and its rotation axis may or may not have flipped during the turbulent precession braking event.

Venus has retrograde rotation now, but a flip of its rotation axis may not be likely. Most initial conditions will drive the spin of Venus towards its present state. The resulting slow spin sets a scenario for the retrograde stable motion purely from atmospheric and internal phenomena

In the mean time we have addressed all enigmatic features,

1: the rotation stop as a combination of the big precession brake and the Correia atmospheric drag mechanism
2: the resurfacing due to a tremendous heat generated by the hot brake, partially melting the planet.
3: the dense carbon dioxide atmosphere as all the carbon was forced out the lithosphere by chemical processes under the extreme heat.
4: the heat itself as residual from the disaster that seems to have ended 500 million years ago.

 

[Mr. Robin Parsons]

Lets see, this thread is about the heating of the Earth's core, not on your (pet) theory of just how Venus became resurfaced 1/2 million years back...right?

As for the "relatively young surface" of the Earth, so far in my life I have had the opportunity to have been in two of the places where the theory of plate tectonics came into development and then acceptance, one in the Yukon, the other in Newfoundland.

The one in the Yukon, a rift valley (sort of) was estimated to be amongst the oldest of terrestrial rocks on the face of the planet, at around 4.2 to 4.5 billion years old, so the idea of a "relatively new face" on the earth, is just kinda wrong(?)?
(at least in those places, it is!)

 

[Andre]

Well, if this pet hypothesis has some merit, it would have some potential for a paradigm shift and not only for Venus, since the same mechanisms are working on Earth. So we're back on track ..eh thread.

 

[Mr. Robin Parsons]

P.S. your #2 gives a "partial melting of the planet's surface" but studies show that the entire surface was done over as they can find NO impact craters older then about 1/2 million years old.

You need enough heating to melt the entire face of the planet, and probably 'plus some' then too!

 

[Mr. Robin Parsons]

Originally posted by Andre
Well, if this pet hypothesis has some merit, it would have some potential for a paradigm shift and not only for Venus, since the same mechanisms are working on Earth. So we're back on track ..eh thread.

Only sorta, as you answer explains a/the makeover, (of Venus) not the mechanisms of regular, and consistent, heating, as the age of the planet implies the requirement that there be a heating source .

 

[Andre]

Right. In the narrative I was cautious:

causing the planet to melt partially or as a whole

just to leave options open. I should have repeated that in the conclusions.

The turning energy of Earth is enough to heat it several 10,000 degrees.

 

[Andre]

not the mechanisms of regular, and consistent, heating, as the age of the planet implies the requirement that there be a heating source.

The heat source is drag within the fluid outer core. The mechanism on Venus is dead as there is no more rotation. On Earth it has just began very hesistantly and intermittently.

 

[Mr. Robin Parsons]

Originally posted by Andre
The heat source is drag within the fluid outer core. The mechanism on Venus is dead as there is no more rotation. On Earth it has just began very hesistantly and intermittently.

Uhmm, got a reference for that one, cause of what I have read the solid inner core is turning slightly differentially to the outer liquid core, measurable in a human lifetime.

As for it being the 'drag' as you state, needs better proving...(?)

 

[Andre]

As for it being the 'drag' as you state, needs better proving...(?)

Absolutely. It's another pet hypothesis but let's say highly controversial. Let's suppose that the mechanism of wandering solid inner cores due to differential precession has happened already on Earth for brief period(s) what would we expect to find?

For one, a much hotter inner Earth than could be expected of natural causes. And we may be looking at that.

But there may be many more effects that we are looking at too, but don't understand.

 

[Mr. Robin Parsons]

In some of what I had read, recently, there was a mention of the cores rotation, "precession" I'm not certain that it was pegged as that or that there was metion of that and it's calculated effects, (but I will, {God willing} if I have the chance, go re-read it for that) but the reality is that there is an ongoing 'differential rotation' of the solid inner core, and it (the solid inner core) is thought to be plating itself, there is evidence of such, (althought I haven't seen it, I'd still give it the benefit of the doubt because of the source) hence the current status would probably be seen as "cooling off". Any 'precessional force' acting upon it, would (probably) simply be "back-timing its thermal history".

 

[Andre]

My last post here https://www.physicsforums.com/showthread.php?s=&threadid=9256 is about the Earth cores, precession and Earth magnetic field. Could it be that? Mr Robin?

 

[Mr. Robin Parsons]

Interesting but I went and did the re-read and the talk of a 1% precessional rate that allows the solid inner core to rotate once extra, within the planet, every ~400 years.

So where is the tremendous force that is needed to cause that to brake hard enough as to cause to arise enough friction induced heat as to melt of the surface of a planet?

(cause it takes LOTS of heat to do that)