Layers of the Earth

By: Saagar Parikh

CrustHard and rigid, its the Earth’s outermost and thinnest layer, only a few miles (5 km) thick under the oceans and averaging 20 miles (30 km) thick under the continents. The crust is solid.Composition: Iron, oxygen, silicon, magnesium, sulfur, nickel, calcium, and aluminum

LithosphereMade up of mostly the crust and a tiny bit of the upper mantle, this layer is divided into several constantly (very slowly) moving plates of solid rock that hold the continents and oceans. The Lithosphere is made up of solid rock.Composition: Oxygen, silicon, aluminum, iron, calcium, and sodium

AsthenosphereThe plates of the Lithosphere move (or float) on this hot, malleable semiliquid zone in the upper mantle, directly underneath the Lithosphere. The Asthenosphere is made up of solid rock, just like the Lithosphere.Composition: Oxygen, silicon, aluminum, iron, calcium, and sodium

Difference between the Lithosphere and Asthenosphere

Some differences between Asthenosphere and Lithosphere is how the materials in these layers can flow. Rocks in the lithosphere are "rigid", meaning that they can bend but they cannot flow. Rocks in the asthenosphere are "plastic", meaning that they can flow in response to deformation. Even though it can flow, the asthenosphere is still made of solid (not liquid) rock. The Lithosphere is made up the Crust plus the very upper part of the Mantle, whereas the Asthenosphere is only Upper Mantle material. Both the Lithosphere and the Asthenosphere, however, are both made of solid rock.

Upper MantleBelow the Asthenosphere lies another layer, stronger and more solid than the Asthenosphere. All layers below the crust down to a depth of about 670 kilometers (416 miles) are known as the upper mantle. Changes in the mantle can cause changes in the deep crust, such as volcanic eruptions.Composition: Olivine, silicon dioxide, peridotite, iron, and magnesium

Lower MantleThe rest of the mantle between the Upper Mantle and the Outer Core is known as the Lower Mantle. It is denser and hotter than the Upper Mantle. The Lower Mantle is more solid than the Upper Mantle.Composition: Olivine, magnesium, iron

Outer CoreThe outer core is the only liquid layer of the Earth; a sea of mostly iron and nickel. It is roughly 1800-3200 miles (2890-5150 km) below the surface, and about 1400 miles (2300 km) thick.Composition: Iron and nickel

Inner CoreAn extremely hot, solid sphere of mostly iron and nickel at the center of the Earth. It is 3200-3960 miles below the surface and about 750 miles in diameter. Composition: Nickel-iron alloy

Interesting Facts about Earth You Probably didn’t Know

• Earth is not a perfect sphere• Earth is spinning just over a thousand MPH, and is revolving around

the sun at just over 67,000 MPH (107, 826 km per hour).• Quakes on the moon occur and are called “Moonquakes”.• Antarctica contains some 70% of Earths fresh water and 90% of its ice.• Since the early 19th century, Earth's magnetic north pole has been

creeping northward by more than 600 miles (1,100 kilometers), according to NASA scientists. The rate of movement has increased, with the pole migrating northward currently at about 40 miles (64 km) per year.

• Earth may once have had two moons. A teensy second moon — spanning about 750 miles (1,200 km) wide — may have orbited Earth before it catastrophically slammed into our present day moon.

Citations• Pappas, By Stephanie. "50 Interesting Facts About The Earth." LiveScience.

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• "Mantle." - National Geographic Education. National Geographic Education, n.d. Web. 07 May 2015.

• Radar, Andrew. "Composition." Geography4Kids.com: Earth Structure:. Geography4Kids, n.d. Web. 07 May 2015.

• "UCSB Science Line." UCSB Science Line. National Science Foundation, 2015. Web. 07 May 2015.