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Thread: core formation

  1. #1 core formation 
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    I was reading this book

    The earth , its birth and growth

    but it is on google books and not complete

    it talked about theories of earth's core

    from page 28 to 31

    and then 32 and 33 are not there

    I want to know

    is the idea that "the components of earths core were molten and then iron and heavy metals went to the centre and the lighter objects went above" correct or was it refused now ??


    and please could you explain what is written here answering the question page 22 ?



    Thanks and sorry for disturbance .


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  3. #2 Re: core formation 
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    Quote Originally Posted by ahmeeeeeeeeeed
    is the idea that "the components of earths core were molten and then iron and heavy metals went to the centre and the lighter objects went above" correct or was it refused now ??
    A planetary perspective on the deep Earth
    David J. Stevenson; 2008

    http://www.billt4.com/Documents/Phys...hEvolution.pdf

    This a good and recent review published in the journal Nature and should answer your questions.


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  4. #3  
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    Thanks very much it is useful

    first i want to say that i am not a student whose specialization is the earth but I just want to understand the last acceptable theory about this specially searching
    for the source of Iron we mine .

    I will type what i (partly) understood


    first after the explosion there ere many parts in the space( of materials)

    then these parts(particles) began to collide with each other hard , making a great temperature and made the proto- earth

    then comes giant impacts and projectiles ((can we say meteorites ??) coming from particles contain much iron and collide with earth that is molten and then the particles of iron from these meteorites go down into the core of the earth .

    Am I right ?? please correct .


    in page 263

    the projectile that contain iron collide with the proto earth and then some of the proto earth magma separte and gets away forming the moon.

    Iron from the projectile sinks through the earth that is molten.

    in page 264

    I want you _ please_ to explain the "a" example simply or more simply as this article is well simple.

    and what is the difference between these and the theory that is refused here

    http://books.google.com/books?id=Bw8...%20%3F&f=false

    page 28

    is the difference that in this article the earth is molten but in the book theory the earth is not ??

    sorry for disturbance again , if what i said was right , it would be the last!
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  5. #4  
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    Quote Originally Posted by ahmeeeeeeeeeed
    Thanks very much it is useful

    is the difference that in this article the earth is molten but in the book theory the earth is not ??

    sorry for disturbance again , if what i said was right , it would be the last!
    Yes and no. In Stevenson's article he suggests that the core may contain a "memory" of its formation. There is not a final known answer or refutation. There is still much to be learned. When it comes to fine details we may never know. We can determine the mass of the Earth and Moon, we can determine its elemental composition and that of the Moon's surface directly, and we have some idea through the composition of both their lavas (magmas) and through seismic studies of what is down below. We can do the same for meteorites here on Earth and by space missions to bodies that are not. Recently, in 2005, it was determined that the core has a "super rotation" in respect to the mantle. In other words, by a small amount the core rotates faster than the rest of the Earth. This was determined through seismic studies.

    There is no "last" question. You have many years of question asking ahead of you, as we all do. I answer your questions because I desire to, it is not a "disturbance", but I suggest that you keep asking, forever, it is how we learn things.
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    ok , thanks very much

    but is the rest of my reply (making a summary to the article) right ??
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  7. #6  
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    Quote Originally Posted by ahmeeeeeeeeeed
    ok , thanks very much

    but is the rest of my reply (making a summary to the article) right ??
    Unfortunately, it is not that simple. The Earth has enough mass that the core can be solid (to use Stevenson's term, frozen) but still superhot and what would be molten at the surface, but is solid at the core's pressure at the center of the Earth. Please understand that we do not know precisely every thing that happened and the order of those occurrences, or what is happening now at the core with any extreme precision. We have much yet to learn and many tantalizing questions. I would say they are parallel explanations with slightly different phrasing, but separated in time by almost thirty years. We have learned much in that time.
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  8. #7  
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    yes I read that also.

    ok what about this

    in page 263

    the projectile that contain iron collide with the proto earth and then some of the proto earth magma separte and gets away forming the moon.

    Iron from the projectile sinks through the earth that is molten.

    in page 264

    I want you _ please_ to explain the "a" example simply or more simply as this article is well simple.
    i know they are just theories.

    and as I told you i am interested in the iron we mine more that the core formation , is it likely that the iron we mine was formed from these collisions of embryos ??

    even if the core was solid , we dont mine iron from the core !.
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  9. #8  
    Geo
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    The Planetiod was 110K hotter than today. It's a very good retainer of heat, that's 4.55Ga. So, it's gone from a accretionary disk to a planetiod, to Earth, and only lost 110K?

    The early stages in the Earth's formation where dominated by bombardments, punctuated by moments of quiesscence.

    Iron, which was created in a picosecond in a Supernovae, is now part of your bloodstream.
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  10. #9  
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    Quote Originally Posted by Geo
    The Planetiod was 110K hotter than today. It's a very good retainer of heat, that's 4.55Ga. So, it's gone from a accretionary disk to a planetiod, to Earth, and only lost 110K?

    The early stages in the Earth's formation where dominated by bombardments, punctuated by moments of quiesscence.

    Iron, which was created in a picosecond in a Supernovae, is now part of your bloodstream.
    Yes, and additional heat through radioactive decay has help maintain its temperature, but it is cooler at the surface now;ie. differential cooling.
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  11. #10  
    Geo
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    Quote Originally Posted by Geo
    The Planetiod was 110K hotter than today. It's a very good retainer of heat, that's 4.55Ga. So, it's gone from a accretionary disk to a planetiod, to Earth, and only lost 110K?

    The early stages in the Earth's formation where dominated by bombardments, punctuated by moments of quiesscence.

    Iron, which was created in a picosecond in a Supernovae, is now part of your bloodstream.
    Geez, I wish I didn't have those 12 bourbons last night. What a load of crap!
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  12. #11  
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    Quote Originally Posted by Geo
    Quote Originally Posted by Geo
    The Planetiod was 110K hotter than today. It's a very good retainer of heat, that's 4.55Ga. So, it's gone from a accretionary disk to a planetiod, to Earth, and only lost 110K?

    The early stages in the Earth's formation where dominated by bombardments, punctuated by moments of quiesscence.

    Iron, which was created in a picosecond in a Supernovae, is now part of your bloodstream.
    Geez, I wish I didn't have those 12 bourbons last night. What a load of crap!
    That would be PWI, posting while intoxicated. So, please, take another shot, err, I mean, what did you mean to say.
    I'm sorry, my responses are limited. You must ask the right question.

    "The track of a glacier is as unmistakable as that of a man or a bear, and is as significant and trustworthy as any other legible inscription"
    John Strong Newberry; 1873

    "From observations upon living glaciers, and from the known nature of ice, we may learn to recognize the track of a glacier as readily and unmistakably as we would the familiar foot-prints of an animal." G. F. Wright 1891 (108-109)

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  13. #12  
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    Please simply explain this

    If the material is
    mixed down to a small scale (perhaps even to the point where there are
    centimetre-sized droplets of iron immersed in the liquid silicate) then
    the iron and silicate can chemically and thermally equilibrate at high
    temperature and pressure (Fig. 3a). The composition of the core and
    the iron content of the mantle were presumably set during these equilibration
    episo
    des

    please explain the whole paragraph and


    what does "equilibrate" mean here ??
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  14. #13  
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    Quote Originally Posted by ahmeeeeeeeeeed
    Please simply explain this

    If the material is
    mixed down to a small scale (perhaps even to the point where there are
    centimetre-sized droplets of iron immersed in the liquid silicate) then
    the iron and silicate can chemically and thermally equilibrate at high
    temperature and pressure (Fig. 3a). The composition of the core and
    the iron content of the mantle were presumably set during these equilibration
    episo
    des

    please explain the whole paragraph and


    what does "equilibrate" mean here ??
    to come into balance

    Think of a cake batter at the point where you add melted butter and mix it in, and everything becomes uniform and to the same temperature.

    That is a very simplistic explanation and at the core and mantle we are talking about extreme environmental conditions of very high temperature, pressure, and viscosity wherein any mixing will take extreme long periods of time and in all likelihood is still occurring.
    I'm sorry, my responses are limited. You must ask the right question.

    "The track of a glacier is as unmistakable as that of a man or a bear, and is as significant and trustworthy as any other legible inscription"
    John Strong Newberry; 1873

    "From observations upon living glaciers, and from the known nature of ice, we may learn to recognize the track of a glacier as readily and unmistakably as we would the familiar foot-prints of an animal." G. F. Wright 1891 (108-109)

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  15. #14  
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    Thanks the view is better now

    Do they make a compound or just a mixture ??

    the iron mixed doesn't descend to the core ,does it ??
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  16. #15  
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    Quote Originally Posted by ahmeeeeeeeeeed
    Thanks the view is better now

    Do they make a compound or just a mixture ??

    the iron mixed doesn't descend to the core ,does it ??
    I assume that you are referring to the mixture in the mantle. At the core mantle interface it is possible. In the mantle itself there are convection currents which is the mechanism for the Earth to conduct heat up toward the lithosphere. There is a boundary called the D" that may be where these convection currents originate, research continues. I must state again that things happen very slowly compared to a human time span and that the viscosity's are high.

    Maybe this is a good time to point out that when the elemental compositions, ie. what elements they are composed of, is measured for lavas and magmas that it always is different for different eruptions, both in time and location. By the time molten rock reaches the surface its composition is both what it was originally and what it has picked up along the way to the surface.
    I'm sorry, my responses are limited. You must ask the right question.

    "The track of a glacier is as unmistakable as that of a man or a bear, and is as significant and trustworthy as any other legible inscription"
    John Strong Newberry; 1873

    "From observations upon living glaciers, and from the known nature of ice, we may learn to recognize the track of a glacier as readily and unmistakably as we would the familiar foot-prints of an animal." G. F. Wright 1891 (108-109)

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