Anglagard writes:
A minor point in an otherwise largely accurate description.
Rahvin writes:
Most of the Earth is still molten, and it's far from homogenous.
Hate to disagree, but I suppose there is a first time for everything.
Most of the Earth is solid. The structure from top to bottom is crust, solid mantle, a plastic layer in the mantle around 20-50km down but only a few km thick. 1800 more miles of solid mantle, a liquid outer core and a solid inner core. The mantle makes up the majority of the Earth by both volume and mass and it is solid.
The issue of where is "half-way" down can be troublesome. Math states that the volume of a sphere is four thirds Pi R cubed. When you first gut-think half-way down, you are dividing the earth into roughly 1/8ths and 7/8ths. The volumetric half way point down into a sphere is about .79R (the cube root of .5) from the center.
The earth is some 6371 km in R, average radius, (or about 3960 miles). This means that half of the earth is only below about 816 miles, something akin to the trip from Detroit to New York, well above Anglagards 1800 mile thickness of the mantle.
"Most" can be an "optical illusion" of sorts when not thought out.
- xongsmith, 5.7d
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