What do we know about the interior of the Earth?
Five billion years ago the Earth was formed by a massive conglomeration of space materials. The heat energy released by this event melted the entire planet, and it is still cooling off today. Denser materials like iron (Fe) sank into the core of the Earth, while lighter silicates (Si), other oxygen (O) compounds, and water rose near the surface.
The earth is divided into four main layers: the inner core, outer core, mantle, and crust.
The core is composed mostly of iron (Fe) and is so hot that the outer
core is molten, with about 10% sulfur (S). The inner core is under such
extreme pressure that it remains solid. Most of the Earth's mass is in
the mantle, which is composed of iron (Fe), magnesium (Mg), aluminum
(Al), silicon (Si), and oxygen (O) silicate compounds. At over 1000
degrees C, the mantle is solid but can deform slowly in a plastic
manner. The crust is much thinner than any of the other layers, and is
composed of the least dense calcium (Ca) and sodium (Na)
aluminum-silicate minerals. Being relatively cold, the crust is rocky
and brittle, so it can fracture in earthquakes. (Univ. of Nevada)
This is a brief summary of our knowledge of the earth's interior. For further information, see: University of Nevada
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