What are the Layers of the Earth

by Tega Jessa on September 19, 2010

What are the Layers of the Earth

Layers of the Earth

There is more to the Earth than meets the eye. While we have been busy discovering what lies beyond our world’s atmosphere there are still many mysteries down here that haven’t been fully explored. One of them is the interior of the Earth. However, advances in seismology give us more information than was available even 100 years ago. One crucial piece of information we now know is what are the layers of the Earth.

The Earth is not a uniform sphere with the same density throughout. Of course it isn’t quite hollow either like it is inferred in classic science fiction novels like “Journey to the Center of the Earth.” We know that the Earth has layers and each layer has something unique about it that affects many of the key processes of nature on our planet.

The first layer that everyone is familiar with is the Earth’s crust. This is the portion of the earth that all life whether it lives on the highest point of land or in the deepest part of the ocean resides. Compared with the other layers it is the thinnest. It also has the greatest variance in its thickness. At some points the Crust is as thin as 5km while others it can top out at 70km. The majority of the crust is made of silicates. It is separated from the rest of the Earth’s layers by a boundary called the Moho. This is where the composition and state of rock changes as it enters into the next layer.

The layer of the Earth beneath the Crust is the mantle. A good majority of this is molten rock and it has more dense elements in its make up. Many of the precious metals get their starts here as well new crust. The mantle is like a near incomprehensibly vast subterranean ocean on which the Crust floats. The convection currents of magma in the mantle cause seismic activity in the crust making faults and shifting continents over time.

The last and most important layer of the earth is the Core. The Core is the densest part of the Earth. It is mostly composed of iron. This is part of the earth is mostly solid, however there is evidence from seismographs and other instrumentation that it is not uniform in density. The rotation of the iron core is what gives the Earth its magnetosphere, the magnetic field that protects us from cosmic radiation allowing life to thrive.

We have written many articles about the Earth layers for Universe Today. Here’s an article about the layers of the Earth’s atmosphere, and here’s an article about the layers of the Earth.

If you’d like more info on Earth, check out NASA’s Solar System Exploration Guide on Earth. And here’s a link to NASA’s Earth Observatory.

We’ve also recorded an episode of Astronomy Cast all about Earth. Listen here, Episode 51: Earth.

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