Earth Layers Facts

Earth Layers Facts
The earth's layers are made up of an inner core, an outer core, the lower mantle, the upper mantle, and the outer solid crust. If you could cut the earth in half you would see that it looks similar to an onion. However the upper and lower mantles make up a large portion of the earth's layers when compared to the other layers. The crust is extremely thin when compared to the mantle, and occasionally some of the deeper layers of the earth reach the crust when volcanoes erupt or when earthquakes occur.
Interesting Earth Layers Facts:
The very inner core of the earth is believed to be solid. It is believed to be made up of iron and some nickel. Because people cannot reach the core there is some debate as to whether it is truly solid, but many scientists believe that it is because it is able to deflect seismic waves (energy waves produced by volcanoes or earthquakes).
It is believed that the inner core is solid because of the extremely high pressure that would make it impossible for the iron to melt.
The outer core is liquid, and scientists believe it is made up of iron, smaller amounts of nickel, and some other lighter elements in trace amounts. Some scientists believe that the outer core rotates faster than the rest of earth, but this has not been proven 100%.
The mantle is separated into the upper and lower mantle. They are separated by a transition zone. Although made up of solid rock, the mantle is not completely hard. It is similar to play dough because it is moldable, but it is also extremely hot. The movement of the mantle is what causes volcanoes to erupt and earthquakes to occur.
The earth's outer layer is the crust. It is made up of solid rock, and granite, and topped with sand, crushed rock, and water or soil at the surface (depending on whether it is an oceanic or continental crust).
The inner core is approximately 1515 miles in diameter.
The outer core is approximately 1408 miles in diameter.
The earth's mantle is approximately 1800 miles deep, and the earth's crust varies between 3 to 43 miles deep.
Earth's inner and outer cores combined are about the same size as Mars.
Scientists can drill holes to study the earth's crust but in order to study deeper layers they must study seismic waves.
The earth's crust can be continental or oceanic. A continental crust is the type found underneath the world's continents. The oceanic crust is the type found beneath the ocean.
There is a mine in South Africa that reaches 3.9km below the earth's surface. It is the world's deepest mine but it barely scratches the crust's surface.
Tectonic plates are comprised of pieces of the crust and the outer mantle. These plates move slowly, and sometimes bump each other and cause earthquakes. Where these plates meet are called fault lines.
Earthquakes and volcanoes occur from activity in or below the earth's crust.

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