The solidification of the inner core may have strengthened Earth's magnetic field.
Earth's core is a billion years old : Read more
Earth's core is a billion years old : Read more
Earth's core is a billion years old
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Yes, my interest ran similar, my main interest in such things - how do they know, or figure out such?
Hello again, Broadlands.
The composition is largely based on pure estimates, as one might imagine. This is a direct quote from Wiki on the earth's core*:
"There is still no direct evidence about the composition of the inner core. However, based on the relative prevalence of various chemical elements in the Solar System, the theory of planetary formation, and constraints imposed or implied by the chemistry of the rest of the Earth's volume, the inner core is believed to consist primarily of an iron–nickel alloy.
At the known pressures and estimated temperatures of the core, it is predicted that pure iron could be solid, but its density would exceed the known density of the core by approximately 3%. That result implies the presence of lighter elements in the core, such as silicon, oxygen, or sulfur, in addition to the probable presence of nickel.[28] Recent estimates (2007) allow for up to 10% nickel and 2–3% of unidentified lighter elements.[4]
According to computations by D. Alfè and others, the liquid outer core contains 8–13% of oxygen, but as the iron crystallizes out to form the inner core the oxygen is mostly left in the liquid.[4]
Laboratory experiments and analysis of seismic wave velocities seem to indicate that the inner core consists specifically of ε-iron, a crystalline form of the metal with the hexagonal close-packed (hcp) structure. That structure can still admit the inclusion of small amounts of nickel and other elements.[17][29]
Also, if the inner core grows by precipitation of frozen particles falling onto its surface, then some liquid can also be trapped in the pore spaces. In that case, some of this residual fluid may still persist to some small degree in much of its interior.[citation needed]. "
end quote.
It is likely these lighter elements were estimated as they simply represent most of the elements that exist in the universe higher than hydrogen, helium and lithium (except nickel). Note that D. Alfè et al. suggest the presence of 8-13% of that pesky oxygen in the outer core.
It does seem like a bit of a WAG.
* https://en.wikipedia.org/wiki/Earth's_inner_core#Composition
Yes, it is clearly a SWAG. But I had to chase down the oxygen aspect of the outer core. And here is what I found in the abstract * :
"The investigation is based on the application of the implementation of quantum mechanics known as density functional theory. We shall show that these techniques are very accurate at predicting the properties of iron, and therefore can be usefully used to study the properties of the core."
end quote
From this they somehow managed to guess that the outer core contained a very light element, oxygen, at 8%-13% of the outer core content.
It certainly appears to be a bit of a SWAG, perhaps even a tad more.
"Temperature and composition of the Earth's core" :
My response to the same question elsewhere - and congratulate to asking questions, even if it is tainted by personal opinion on the response - was much the same as Chem 721 but add some detail.
No, it is not a personal opinion "SWAG", as can be seen from the quote. The density and chemistry fits perfectly as well as the formation theory of the differentiated planet, and we have no other alternative. The term "direct evidence" is an opinion - because how do you define "direct/indirect" in a testable way? - but in this case it means we have no example of core material transported to the surface which annoys some. The rest accepts it is an iron core and move on with questions that we have no clear answer to.
I should also add that the mission to Psyche intends to sample what we think is a core remnant asteroid. [ https://en.wikipedia.org/wiki/Psyche_(spacecraft) ]. With a bit of luck we will test the core composition in more detail by 2026-2031. Meanwhile, we have the pallasites which formation constraint now has forced people to conclude that they sample the core/mantle interface of partially differentiated bodies [ https://www.sciencedirect.com/science/article/abs/pii/S0012821X20303630?via=ihub ]. . Yes, they contain lots of iron!
No, it is not a personal opinion "SWAG", as can be seen from the quote. The density and chemistry fits perfectly as well as the formation theory of the differentiated planet, and we have no other alternative. The term "direct evidence" is an opinion - because how do you define "direct/indirect" in a testable way? - but in this case it means we have no example of core material transported to the surface which annoys some. The rest accepts it is an iron core and move on with questions that we have no clear answer to.
I should also add that the mission to Psyche intends to sample what we think is a core remnant asteroid. [ https://en.wikipedia.org/wiki/Psyche_(spacecraft) ]. With a bit of luck we will test the core composition in more detail by 2026-2031. Meanwhile, we have the pallasites which formation constraint now has forced people to conclude that they sample the core/mantle interface of partially differentiated bodies [ https://www.sciencedirect.com/science/article/abs/pii/S0012821X20303630?via=ihub ]. . Yes, they contain lots of iron!
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Metallic meteorites have repeatedly struck the earth and they are iron-nickel. Since they purportedly represent the former interiors of a much larger body (proto-planet say) which was smashed probably by collision in the asteroid belt, why not iron-nickel in the interior of the earth also? The denser iron, nickel and maybe uranium would differentiate in a liquid state during earth's violent formation. This is fundamental extractive metallurgy where the slag (the earth's crust) floats on the dense underlying metal (iron). Same as happens in the manufacture of iron in a blast furnace. The earth is too heavy to have slag all the way to the centre so why not a metallic core such as some meteorites and asteroids exhibit.
There is no doubt about an iron-nickel core (1). We would not have a magnetic field without it. The issue was really about the lighter elements. The concept still is intriguing, especially about oxygen. I wonder if it is true. If there really is a lot of oxygen trapped in planetary cores, it could be released periodically over time to provide a substantial oxygenated atmosphere, if it were made gaseous. Not likely lasting long, but it could explain unique iron formations in earth's geological record.
I wonder if Broadlands is still out there and can shoot down any notion of primordial oxygen in or near the core, and the potential for periodic mass releases as a gas over geological time. He is an expert on this stuff. Stranger things have been known to happen.
(1) https://en.wikipedia.org/wiki/Planetary_differentiation
Here is some additional information on the potential for oxygen inside the earth :
www.livescience.com
Tons of Pressurized Oxygen Could Be Hiding Out in Earth's Molten Iron Core
Earth's vast magma oceans, roiling deep beneath our feet, seem to be pumping oxygen into the planet's liquid core.
www.livescience.com
Its the Nuclear Reactor burning Uranium. Much heavier than iron it will sink down to the very center. It is the central core that is keeping the earth hot. Just for the technical folks the over pressure crushing the Uranium will increase its density so that a natural U reactor will go critical. Poison fission products (Ni, I, Cs, Sr etc) will diffuse up to the surface (never quite makes it though) so the reactor will oscillate [off and on] at a freq of several million years. Need a PHD student to do all the calculations in detail to prove. My back of the envelope (OK a bunch of envelope) shows it to be worth perusing OK I'm a nuclear engineer and know what I am talking about.
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A new study conducted by researchers from the University of Texas has revealed the age of the Earth's inner core. Over the years scientists have made different assumptions about how old the inner core is, with versions ranging from half a billion to 4.5 billion years-old, indicating that it would have formed when the the planet was born. The findings of the new research, published on 13 August in the journal Physical Review Letters, claims that the Earth's inner core is between 1 billion and 1.3 billion years old, a date coincides with the strengthening of the planet’s magnetic field.
To estimate the age of the Earth's inner core, researchers recreated its conditions on a tiny scale, heating a small piece of iron to 4,490 degrees Fahrenheit (2,727 degrees Celsius) and placing it between two diamond anvils to recreate the extreme pressure the inner core experiences. The piece of super-heated iron was then measured to observe how it conducts heat, the same way the inner core transfers heat to the outer core.
This detail allowed the researchers to calculate the thermal cooling of the core that powers the geodynamo process, which creates the planet's magnetic field. Researchers found that the geodynamo drew on about 10 terawatts of energy from the cooling core. After calculating the amount of energy loss, they were able to calculate the inner core's age.
The inner core of our planet is notoriously difficult to investigate, being that it is over 6,300 kilometers (roughly 4,000 miles) away from us. The deepest humanity has ever drilled into the planet is a frankly minuscule 12 kilometers (7.5 miles). Seismologists long ago worked out that the physical properties of the core could be determined using the sound waves produced during earthquakes, but its age is less certain, with estimates ranging from 2 billion to a mere 0.5 billion years old. Today, a team of researchers led by the University of Liverpool has narrowed this down, revealing that the age of the inner core is somewhere between 1 and 1.5 billion years old. The study is published in Nature.
The inner core is our planet's deepest layer. By assessing the types of sound waves that do or do not travel through the core, scientists have worked out that it must be composed of iron and nickel. Not only that, but seismologists are confident that this sphere is slightly larger than Pluto, with a diameter of 2,440 kilometers (1,500 miles).
The interaction of the static inner core with the swirling outer core generates the Earth’s magnetic field which protects life from dangerous levels of solar radiation. Knowing when the inner core formed – in an event known as the “iron catastrophe” – could enlighten scientists as to when this stable, protective magnetic field began to be generated.
If indeed the inner core formed around 1 to 1.5 billion years ago as the authors suggest, then this would coincide with the rise of simple multicellular life on Earth, such as red algae*, approximately 900 million years ago, resulting from the growth of the protective magnetic field.
To estimate the age of the Earth's inner core, researchers recreated its conditions on a tiny scale, heating a small piece of iron to 4,490 degrees Fahrenheit (2,727 degrees Celsius) and placing it between two diamond anvils to recreate the extreme pressure the inner core experiences. The piece of super-heated iron was then measured to observe how it conducts heat, the same way the inner core transfers heat to the outer core.
This detail allowed the researchers to calculate the thermal cooling of the core that powers the geodynamo process, which creates the planet's magnetic field. Researchers found that the geodynamo drew on about 10 terawatts of energy from the cooling core. After calculating the amount of energy loss, they were able to calculate the inner core's age.
The inner core of our planet is notoriously difficult to investigate, being that it is over 6,300 kilometers (roughly 4,000 miles) away from us. The deepest humanity has ever drilled into the planet is a frankly minuscule 12 kilometers (7.5 miles). Seismologists long ago worked out that the physical properties of the core could be determined using the sound waves produced during earthquakes, but its age is less certain, with estimates ranging from 2 billion to a mere 0.5 billion years old. Today, a team of researchers led by the University of Liverpool has narrowed this down, revealing that the age of the inner core is somewhere between 1 and 1.5 billion years old. The study is published in Nature.
The inner core is our planet's deepest layer. By assessing the types of sound waves that do or do not travel through the core, scientists have worked out that it must be composed of iron and nickel. Not only that, but seismologists are confident that this sphere is slightly larger than Pluto, with a diameter of 2,440 kilometers (1,500 miles).
The interaction of the static inner core with the swirling outer core generates the Earth’s magnetic field which protects life from dangerous levels of solar radiation. Knowing when the inner core formed – in an event known as the “iron catastrophe” – could enlighten scientists as to when this stable, protective magnetic field began to be generated.
If indeed the inner core formed around 1 to 1.5 billion years ago as the authors suggest, then this would coincide with the rise of simple multicellular life on Earth, such as red algae*, approximately 900 million years ago, resulting from the growth of the protective magnetic field.
Here is a mathematical derivation of age of earth and ages of some other planets that we use in astrology ...
This age is derived by an extremely ancient science which was called as Kaalchakra ... Here is the link which has this calculation ...
Age of earth ... 4.54991934 billion human solar years
This age is derived by an extremely ancient science which was called as Kaalchakra ... Here is the link which has this calculation ...
Age of earth ... 4.54991934 billion human solar years
I doubt it, since there is no known "reactor" here. Geoneutrinos match the background radioactivity, not fission.
It is a hypothesis that a geomagnetic field protects the atmosphere - it is mostly the atmosphere that protects and nurture life - but such a late geodynamo has had little time for protection so seems of little value.
As it happens, Earth may lose more atmosphere than Venus (no geodynamo field) and Mars (no geodynamo field).
[ http://astrobiology.com/2020/11/surprisingly-little-water-has-escaped-from-venus.html ]
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