What are the Layers of the Earth

Earth is the planet that we live on, our home. It is also called the Blue Planet as it appears blue in space. About 4.54 billion years ago, earth began to support life. The third planet from the Sun, there are four main layers that make up planet earth. I am sure you would like to know more about what are the layers of the earth. Let us learn some important facts about the layers of the earth from the following paragraphs.

What are the Layers of the Earth

There are four main layers of the earth. The following details will help you understand what are the layers of the earth in detail.

The Crust
The first layer of the earth is called the crust. The crust is the layer of the earth that sustains life on earth. The igneous rocks, metamorphic rocks and sedimentary rocks make up the crust. There are two types of crust, continental crust and oceanic crust. The continental crust is made of rocks that are similar to granite. The depth of this crust is about 30 km to 50 km. Specific gravity of the continental crust is about 2.7. The oceanic crust is thinner than the continental crust. This layer of the earth is made up of igneous rocks, basalt, diabase, and gabbro. The specific gravity of this layer is about 2.9.

The Mantle
The second layer of the earth is the mantle. It is also the middle layer of the earth that is made up of silicate rocks. These rocks are rich in iron and magnesium. The mantle is the thickest layer of the earth and makes up about 84% of the Earth's volume. The mantle is divided into upper mantle, transition zone, lower mantle and D".

The upper mantle consists of the lithosphere and the asthenosphere. Lithosphere is the hard rock layer of the mantle. It is made up of tectonic plates that float independent of the other. The athenosphere is below the lithosphere that is made of viscous, yet solid rock. It moves from time to time due to its viscosity. The transition zone of the mantle is made up of peridotite. It is made of coarse grain igneous rocks. The lower mantle is below the transition zone. One does not know much about the lower mantle and it is thought that it is a homogenous layer. Next is the D" zone of the mantle. It is the boundary layer of the mantle and the liquid outer core.

The Outer Core
The outer core is made up of liquid iron and nickel. It also contains small amounts of light weight elements. It is said it is a ball of really hot metals. The light weight elements are thought to be sulfur and oxygen as they are able to dissolve in hot, liquid iron. The outer core spins over the inner core due to the rotation of the earth. This spinning helps in generation of the earth's magnetic compass field.

The Inner Core
The inner core is the last and the deepest of the four main layers of the earth. This is the hottest layer of the earth, with high pressure. It is said the temperature of the earth's core is higher than the surface of the sun. This heat helps in mobilizing the outer core and the mantle. The high pressure causes the contents of the inner core to remain solid. This was all about what are the layers of the earth. Let us have a look at what are the layers of the earth made of.

What are the Layers of the Earth Made Of

One would like to know what are the layers of the earth made of. Their composition helps us understand the way our earth is built and how it influences many other phenomena occurring on the surface. The continental crust is mostly made up of granite, limestone and sandstone. The ocean crust is primarily made up of basalt. It contains limestone, iron and magnesium as well. The mantle, the middle layer of the earth is made up of iron and magnesium. The outer core consists of liquid iron, nickel and lighter elements in small quantities. The outer core is made up of a very hot iron-nickel alloy.

How Deep are the Layers of the Earth

The next important question that helps us understand the facts about the layers of the earth is about their depth. Let us see how deep are the layers of the earth. The crust is about 30 km to 50 km in depth. The mantle is about 2,200 kilometers in depth. The outer core is about 2,900 kilometers in depth and the inner core is about 5,150 km in depth. If you are wondering how thick are the layers of the earth, then the crust is about 35 and 75 kilometers thick. The mantle is 5 to 10 kilometers thick, when measured from the deepest basins of the oceans. The outer core is about 2300 km thick and the inner core is about 1220 km thick.

How Hot are the Layers of the Earth

We shall now see the answers related to how hot are the layers of the earth. The temperature depends upon the location and depth of the crust. Thus, it may vary from -56.7º C to 398.9º C in temperature. The mantle is about 1000º C in temperature. The outer core has a temperature range of about 4000º C to 6,100º C. The hottest layer of the earth, the inner core is about 5,000º C to 7,000º C.

These were some facts about the layers of the earth. As you can see there are four main layers of the earth that consists of different composition. Hope you have found some useful information on what are the layers of the earth from the above paragraphs.