My Personal Science Nerd

Earlier I did an article informing you about the Earth’s atmosphere. Well, now I feel that an article should be written about a topic that is equally as important: the layers of the Earth.

When you think about Earth, at least the non-atmospheric portion of it, you get the image of a big round ball of rocks and water. That, to a certain extent is true. But what is on the inside of our planet aside from a wonderful personality. Is Earth just a shallow ball on the inside that is waiting to collapse in on itself or it’s it composed of different layers that in turn are composed of different element and compounds? If you were to guess the latter of the two ideas then you would be correct. Either way, I still think you should read this article.

So, I will start off by listing the different layers of the Earth and then will go more in depth as we proceed through the article. The Earth is composed of four basic layers: crust, mantle, outer core, and inner core. Each of these layers are vastly different from each other and are always changing, sometimes very violently, as time continues. The first and outermost layer is called the crust. This is the ground you walk on or the ocean floors. The second layer is the mantle. This layer is the thickest of all the layers (when the outer and inner core are not combined). The core is what follows the mantle. The core can be broken into two layers: the outer core and the inner core.

As mentioned earlier, the crust is the outermost layer. It is made up of two types of plates: continental and oceanic. As you scan the crust, one would find that it varies in its thickness, ranging from roughly 5 km to 70 km thick. The locations where the crust is thicker is the continental plates whereas the thinner portions are the oceanic plates. Earth’s crust is mainly a composition of alumino-silicates, which are minerals made of aluminum, silicon, and oxygen.

The second layer is called the mantle. The mantle is roughly 2900 km thick and can be divided into the upper mantle and the lower mantle. A majority of our planet’s internal heat can be found in the mantle.     Because of this heat, convection occurs which allows for plate tectonics to take place (I will discuss that in another essay). In the upper mantle there exists what is called the asthenosphere. This part of the mantle is soft and plastic. Pressure is the cause for its characteristics. On top of the asthenosphere is the lithosphere. This layer can both include the uppermost regions of the mantle as well as the crust. The lithosphere is what is broken up into the tectonic plates. I will talk about the stress that is placed on it later when I do seismology. The mantle is composed of Fe,  Mg, Al, Si, and oxygen silicate compounds. In the mantle, the temperatures are extremely hot, ranging from roughly 500 to 900 degrees Celsius and increasing to well over 4,000 degrees Celsius as you approach the core.

The third layer is called the outer core. The outer core is roughly 2300 km thick and made up of a nickel-iron alloy which is in its liquid form. The temperatures in this part of Earth’s interior can soar to around 6100 degrees Celsius. As I mentioned earlier, the outer core is composed of nickel-iron alloy which is able to influence the Earth’s magnetic field due to eddy currents, or Foucault currents, which help to protect us from the solar winds that the Sun emits. Additionally, the reason this alloy is not solid is because the pressure is not strong enough to make it so.

The last layer is the inner core. This solid layer of the planet is the innermost and hottest part of Earth, with temperatures possibly reaching the temperatures as the surface of the sun. It is thought to be composed mainly of iron, this being based off of the abundance of chemical elements in the solar system.

This concludes my article about the layers of the Earth. I will go into the mechanics of seismology in a later article. Thanks for reading!

Photos came from Wikimedia Commons.

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core, crust, Earth, layers, mantle