I am learning earth science and part of my notes say: The earth, by physical properties, is divided into 3 key regions: -lithosphere -asthenosphere -core Is the above correct way of division according to physical properties? I don't understand why the earth is divided into lithosphere, asthenosphere, and core. And where does the mesosphere go? (lithosphere + asthenosphere + core isn't the "whole" earth)
Well, I assume that you dont think the atmosphere is technically part of the earth? It is, but its not geology, which is what earth science used to be called in my neck of the woods. Plus your notes are somewhat abbreviated, as far as I know its not so much physical properties as physical condition. The core is likely nickel iron, semi solid, very hot, the asthenosphere is similar but less hot, and lighter, and the lithosphere is the outer crust, which is solid. For more answers, look up wikipedia.
I actually mean the "mesosphere" that is inside the earth...not the one up on the atomsphere I know that the earth's interior can be divided in two ways, by composition or by physical properties. Dividing the earth's interior by chemical properties (composition) gives: crust, mantle and core How about by dividing the earth's interior physical properties? (how many areas can it be divided into?)
Physical properties: Lithosphere (solid) Asthenosphere (plastic) Mesosphere (it goes here. this part is liquid) Core (Porous solid) Chemical properties: Crust (Granitic, Andesitic, and Basaltic) Mantle (Peridotite and other ultramafic minerals) Outer Core (Iron-nickel) Inner Core (Radioactive potassium? nobody really knows)
Since Kingwinner has posted his question on several forums I guess I can post my reply on several also: Compositionally the Earth has three distinct zones: Core - Iron-nickel Mantle - Basic silicate comparable with the igneous rock peridotite Crust - a 'scum' of mixed composition, but simply divided into a discontinuous upper portion, generally granitic, (forming the continents) and a globe spanning lower portion, generally basaltic, (forming the ocean floor). Structurally the Earth has five zones. Solid - inner core Liquid - outer core Solid - lower mantle - mesosphere Plastic - upper, but not uppermost, mantle - aesthenosphere Solid - Uppermost mantle and crust- lithosphere Remember that all classifications are artificial: they are used to help us understand relationships between things. They are not real in themselves. Facial, please note that the mesosphere is not liquid. The mesosphere is the solid portion of the mantle below the asthenosphere. The core is not porous. Only the inner core is solid and is generally believed to be iron nickel also.
I stand corrected on the mesosphere, ophiolite. I'm not too sure on the core; I read this article on a Science journal published several years ago that suggested a porous nature to the supposedly 'solid' core. Can't find it online anywhere, though.
It's difficult for me to imagine any porosity at the pressures exist within the core. However it may be some form of nano-porosity existing within the crystal structure, rather than between crystals. It may have been deduced from fine detail in seismic data. It sounds sufficiently esoteric I'll try to find out something about it. I'm not too optimistic about that though if you've searched online and I don't currently have access to a University library.
"Because the earth rotates, the outer core spins around the inner core and that causes the earth's magnetism." How come the spinning of the OUTER core gives earth's magnetic field? And why not the INNER core? Does the INNER core spin, too? If so, why?
