How the Insides Work
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Earth’s Major Cores Atmosphere Lithosphere Asthenosphere Moho –––––––––––– Upper Mantle P′ ––––––––––––––– Lower Mantle D″ ––––––––––––––– Liquid Outer Core (LOC) P″ ––––––––––––––– Solid Inner Core (SIC) |
The ball of rock known as Earth has differentiated about as much as it will. There is very little, or none, mixing between the major core layers. The Moho, P′, D″, P″ layers are actually “interface zones” between the core layers where little mixing does occur. These layers are very thin, usually 70 to 150 kilometers thick, perhaps much thinner. I ain’t gonna list the thickness of the cores (radii) since they can vary due to the heat bubbling out of the Earth. Boil and bubble, toil and trouble. Yep, that’s Earth. Your world also. And remember, it is HEAT bubbling out, NOT material, until you get into the Asthenosphere and above.
As said, studying the Earth will open many, many insights into your world. It all depends upon how in-depth you wish to go. 7734, this treatise can largely be ignored for RPG campaign worlds. But I know there are some out there whom like this kind of information. Even if never used. Some even go out of their way to seek learning and knowledge.
Working inside-out...
Solid Inner Core
The SIC is actually hot enough to completely vaporize iron and nickel, some 4500°C to 6000°C. Iron and nickel vaporize at 3134°C and 3186°C, respectively. So... If the SIC is that hot, then what keeps it in a solid form? And the LOC in molten form? Gravitational Pressure, aka, Pressure Freezing, aka, Gravity Freezing. Earth has enough mass to produce enough gravity to create enough pressure to keep the two cores inside the Earth from exploding. The same force is what keeps our star, Sol, from going nova. And you wonder why the Super-Laser on the Death Star causes a planet to explode. Expose the core, and BOOM!, pressure inside finishes the job.
The weakest of the four Fundamental forces in the cosmos is what keeps everything together. Anyone remember the saying, “Duct tape. It’s what holds the universe together.”? To me, this is damned KEWL. The weakest holds everything together. And as Mr. Spock would say with the infamous eyebrow lift, “Fascinating.” My life-long Hero IS Mr. Spock. “Please, Doctor. Logic and reason always finds an answer.”
We hypothesize that the SIC is about 95% iron, 3-4% nickel, and 1% other trace materials such as sulfur (bonds easily with iron), and perhaps some of the Actinides. Then realize some portions of the SIC will have slightly differing composition %, but that is somewhat negligible. Meaning it can ignored. Thus, go with SIC = 95% Fe, 4% Ni, 1% other.
Actinides are some of the densest elements, but come in some of the minutest quantities, could have been created during the HBP. The velocities of some of those impactors could have been fast enough, and massive enough, the collision and heat could have smashed some of the simpler elements into these much heavier elements. The amount would be very small compared to the Earth, but still enough to impart heat during their radioactive decay.
MY Hypothesis Proposal: Overall % of actinidic elements within the entire Earth would amount to about 0.0000001%. And I am probably over estimating the amount...
Liquid Outer Core
We know the outer core of the Earth is in a molten liquid form from over 100 years of seismological studies. When a quake occurs, there are P-waves and S-waves. The S-waves do NOT propagate through “liquids”. P-waves on the other hand, propagate through everything. There is no place ON/IN the Earth that is safe from P-waves.
S-waves
P-waves
The LOC has a very similar composition as the SIC. However, since it is in a molten liquid state, it has more of the trace elements than the SIC. Perhaps only 2-3% trace elements. Since the LOC is liquid, that also means there is convection. Largely thermal and density convection, with some rotational Coriolis effect. Through many experiments, we have discovered that convecting molten (flowing) liquid iron does impart an electrical current into and through the SIC. It is this convection and electrical current that produces Earth’s GMF (Geo-Magnetic Field).
Thermocouples. Why did that pop into me frond? [This came from ADHD. Not me. These kind of Fuzzies are what I call Wild Tangents. I just do not know why Thermocouples popped in where it did. ???]
Wild Tangent: Did you know that you CANNOT produce an electrical current without ALSO producing a magnetic field about that current? You can have magnetism without electricity. But you CANNOT have electricity without magnetism. Then, you can take magnets, spin them about a solid metallic core, and produce an electrical current. KEWL. No? Or reverse it with coils of wire spinning about magnets, like a car’s alternator.
Without the differentiation of the Earth which produced the LOC and SIC which produces a powerful enough GMF, even Earth would have done nothing but squalor in a “microbial” state of life. Even today.
Now think on that. Us Humans owe our greatest of reverence for FeNi. FeNi is Life’s deity. T…H…I…N…K… There should be no other gods except FeNi for any Life. ;-P
Without a large enough FeNi LOC/SIC, no terran planet would be able to produce complex life. Mars is a perfect example. Although we hypothesize Mars may have a FeNi core, it is far too small to generate a powerful enough GMF. This would cause any “Earth”-like conditions to rapidly disappear through a process known as “dynamic stellar interfacial evaporation” (DSIE).
Author’s Note: DSIE is MINE own creation. Do NOT accept it as scientific standard. In other words, any atmosphere and hydrosphere would have been rapidly evaporated and ionized by Insolation, then blasted away by the stellar winds. Additionally, proximity to the star can also create violently toxic atmospheres, such as on Venus.
Wild Tangent Factoid: Did you know that the lightest gas Earth can hold gravitationally is carbon dioxide? CO2? All other lighter gases, including our precious oxygen, escape through my DSIE process. If it were not for the replishment of Earth’s atmosphere from geomorphology and life, Earth would be a Greenhouse Inferno just like Venus. Thus, you’d better be giving Thanks to the Great God FeNi. And his fires of 7734.
BTW: In accordance to me failing memory, DSIE used to be called something like hydrodynamic evaporation. However, “hydro-” tends to refer to only water. That left me with dynamic evaporation. I asked me self, “Where is this evaporation taking place?” At the interface of the stellar winds and GMF. Thus, “stellar interfacial”. That is how I came up with DSIE. Sue me. I claim Titus Jurum. ;-P
See how me Wild Tangents roam about in such an extensive subject?
Upper & Lower Mantles
This is where the Earth begins its great silicaceous core layering. Most of Earth’s FeNi (about 99%) is within the LOC and SIC. And they wondered why the Harvesters used such hugemongous drills on the Earth in ID4 and IDR (Ref: Independence Day movies). And they must use that shielding technology to contain it before it explodes. Shields hold the LOC/SIC, but then slowly expand, allowing the pressure to release, along with some heat. Earth is slowly “grown” into an asteroid field of largely silicaceous rocks with its FeNi core stolen away.
Of course, the Lower Mantle is densest, containing more FeNi than the Upper Mantle. Perhaps also loaded with actinides and rare earth metals that are suspended in situ. Too minute of quantites to fully sink to the cores. There is no intermixing between the UM and LM. It is entirely thermal energy that creates the convection within the UM and LM separately. But not between. “Hot Spots” can develop at the Moho, P′, D″, and P″ interfaces as HEAT builds up within the lower core layer at these interfaces. That Hot Spot then creates a heat-plume within the next core layer, driving convection, which may go through each core layer all the way to the surface.
Hawai'i. Yellowstone.
Just to name two hot spots within the territory the USofA claims.
Through Seismotomography, we have even mapped the sinking plates within the Upper Mantle, as shown above. The darker region shows denser material, faster P-wave propagation.
See how advanced our Seismology has become? We have even mapped a small chunk of what was a particularly dense oceanic crust that is actually sinking into the Lower Mantle through the P′ interface. As I write this. We have mapped the plates along virtually every major Convergent Zone, Divergent Zone, Transform Faults of the Earth’s major crustal plates. Along the Andes Mountains, we see some of the oceanic plate literally diving straight down being that dense, as evidenced by very thin horizontal belts of orogeny. Some slides shallower, as evidenced by Peru region, producing a horizontally thicker zone of orogeny. And the wetern USA is prime example of a very shallow dive from the Farrellon (msp?) Plate.
We have even mapped the chunk of the Farrellon Plate that broke off about ½way into Montana, Wyoming, Colorado, New Mexico. That chunk is lying much deeper in the Upper Mantle, under the Eastern Seaboard. It broke off and “floated”? eastward in the Upper Mantle. Actually, “planed” would be a better word. It planed through the Upper Mantle. Much like the piece of the Titanic that broke off and planed once underwater. Now it is about level and moving towards the Atlantic Divergent Zone. Where in a few, or tens of, millions of years (Ma), it may be uplifted into the Atlantic MOR.
Wild Tangent: ALWAYS remember that geologic time requires Ma, Ga for things to make complete loops within the convection of the Earth’s core layering. I mean this: The North American Plate is moving in a radial movement at about 3 to 7 cm/yr. Or is it mm/yr? Whatever. The western portion is moving faster than the eastern portion. Eventually, the USA may be split in half right up the Mississippi. Gulf of Mississippi (Titus Jurum). We have been mapping some slight rifting along the Mississippi drainage valley from Louisiana to Minnesota. There is also evidence that subduction may begin along the east coast of the USA along southeastern North Carolina. That means Convergent Zone and orogeny. Volcanism.
Possible Subduction Zone North Carolina
The possible subduction zone can be seen as that thin stripe of darker blue just past the Continental Shelf. That would explain all those tremors I kept hearing but kept mouth shut about for all those years. And the reason for the subduction is because the eastern portion of USA is now moving slower than the Atlantic plate. IOW, the oceanic plate is over-running the eastern North American Plate, and since it is denser, it is subducting. Taking the dive.
That would also explain my hearing all those tremors on the east coast. But, no worry. That may not begin but for another few, or tens of, millions of years. Geologic time is very long, slow periods of time. It may well be over 10Ma before any magmatic activity even gets started.
Now I want you to truly think critically. These convection currents within the core layerings of the Earth, are far too slow to detect except through many years, decades of data acquisition. AND I mean many, many, ...many years. Lots of BORING work. Some decades long. Then analysis... Cerebration... Visualization... ... Et cetera... ... Et alia... Science ain’t fast as it seems. Not all science, but geological science of the Earth takes a lot of patient time.
I have always said it is a Disciplined Mind that can only do science. Think Critically enough to do science. It takes LOTS of patience. BORING!
I shall be the first to admit that science can be BORING. I was always one who particularly enjoyed the field work. I loved the outdoors. Me entire life. Even as I am typing this page, I am sitting on me back porch outside. I loved doing actual field work such as repairing geostations (MY nomer.), swapping HDDs, setting up new geostations, etc., et al. My very first day in the field at the YVO and USNPS, I had a Bison come to within two meters of me setting up a new geostation. He kept his eye on me while munching his grass. KEWL! Second day I had a Rainbow. Found the Pot'a'Gold and retired. ;-P
See more wild tangents. Ugghh... Damned ADHD.
Thought Experiment: Can you imagine a mind that runs ideas so damned fast, that even THAT Mind itself cannot keep up with IT self? 7734 NO!! If YOUR mind does not run that fast, you cannot even imagine it. You can ONLY experience IT. Thus, here and now, I apologize for the derailments due to ADHD.
The convection within the Upper Mantle, on its upperside, is what imparts convection and movement into the Asthenosphere, then into the Lithosphere.
Once we are into the Lithosphere, that is where the science of Plate Tectonics comes into play. Can Johnny come out to play? We also have to study Fluid Dynamics to know how the Asthenosphere behaves. In a fashion, one could say the continental crust is like “rafts” floating on the Asthenosphere. But, even that analogy is ultimately wrong since it is DENSITY, not bouyancy, with pressure, at work. Of course, the density and pressure does create a “bouyancy” effect with the lesser dense materials, but it is largely density and pressure and heat. Under enough pressure with enough heat, even solids will act like “fluids” smashing into each other, ripping each other apart, sliding past each other.
Just imagine, Pressure within the Earth can literally “squish” solids into a behaviour akin to a liquid. KEWL as 7734. Pressure, as it is increased, also increases temperature. Thus, those millions of tons of pressure generate tremendous amounts of heat. And Heat is simply trying to escape. Boil and bubble, toil and trouble, goes this Earth. AND, always remember, it IS the heat that is doing all that Shakespearean stuff, NOT the material bubbling out.
“Hot Spots are... Inevitable.”
“Thank you, Agent Smith.”
As heat tries its damnedest to radiate, conduct, and convect lithospherically outwards, THERE SHALL BE HOT SPOTS. Inevitable. This is due to the convection which distributes the heat unevenly throughout the Earth. The convection may take a hot spot in one layer, and plume it hundreds of kilometers to another spot at the next interface zone. Starting coreward, a hot spot and plume that starts under New York City (NO, there is not one) then convection shifts the plume which creates a hot spot underneath Chicago. Make sense? Perhaps NOT that drastic, but you should get the picture. Of course, in this fake scenario, Chicago would not be Chicago. It would be The Great Lakes Volcano. ;-) I created it. I get Titum Jurus. >:-P
Simple Gravity-Density-Viscosity Convection Visualized
The Great Gravity-Viscosity Experiment
Follow instructions:
I did the above experiment about, gads!, has it been over ½century? DAaammnn... WOW! You know your ancient when you reference portions of a century. Over 5! decades ago? Holy 7734, Batman. He could have planted a Redwood seed, and it could be about 20, maybe 30 meters tall. And I used to joke by saying, “I can remember when there was only rock.” ;-P
Here is a global seismotomography of where the Upper Mantle and Lower Mantle are hottest, thus less dense. You can even see how heat is transferring from the two cores (blacked-out region), through the Lower Mantle, into the Upper Mantle underneath the African continental plate in the left image (the big red plume). The other Lower Mantle heat plume is underneath the west coast of the North American Plate. The right image is a latitudinal (E-W) slice through the Earth. The left is a longitudinal (N-S) slice. Red is hottest and less dense, blue is coldest and more dense.
In the right image, notice that Hot Spot in the Lower Mantle underneath the North Pole. And the one at the South Pole has actually plumed heat underneath Antarctica in both the Lower Mantle and Upper Mantle.
Seismotomography mapping material density in cross-section
Ain’t that KEWL? The heat plume from LOC through LM into UM and Lithosphere is what is tearing eastern Africa apart. All that heat also generates a high pressure zone within the Earth. And basically it is HEAT just wanting to get out. Explosively if necessary.
In left image, notice the heat in the word “Upper”. That is the Atlantic Divergent Zone where slab-pull allows the Upper Mantle onto the Lithosphere. Another thought thunked. In both cross-sectionals above, look at all that denser material around the LOC. Now can you see the uneven heat pluming? Heat Never convects nor conducts nor radiates evenly. Ever.
Basically, the Earth is still a boiling, bubbling magma ball. Just that it is now much longer and slower in the process. As heat does escape, the Lithosphere will continue to thicken until Earth becomes a Hot Spot geomorphology planet. Atmospheric replishment will lessen, creating more atmospheric loss due to DSIE; thus Earth’s atmosphere will reach toxic levels of CO2. Perhaps in a few hundred million years.
Remember, Earth cannot gravitationally hold any gas lighter than carbon dioxide. Greenhouse Inferno. So, give thanks to the great FeNi, and the heat IT produces, which generates the geomorphology that keeps the atmosphere replinished. If I am ever to be said to have a “god”, IT would be to hold reverence for the Great FeNi and its heat at the core of our world. In a sense, I worship the christian Hell. But I do not. I find it absolutely so awe-inspiring, it is like a “god” to me.
The Natural World is so full of fascination, why cannot the best plausible explanation just be Natural Processes. Natural Processes are like a deity to me. Okay, enough spirituality. Everyone has one.
Summation
We can literally say that the Great Earth Mother farted ALL life into existence. I know. Politically uncorrect. But, O! how true. ;-)
Now Earth is a boiling, bubbling, toiling, and troubling ball of magma. SOLID magma, excepting LOC. The heat within is just still trying to escape into space. Wasted. If we could trap Earth’s heat, we could provide almost free power for our global civilization. Only problem, those torturously slow convection currents will tear apart anything we use to harness that power.
“Inevitable.”
“Thank You, Agent Smith.”
Arsehole.
— The Unknown Atheist
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