What is Structure & Composition of the Earth:
It may look like the Earth is made up of one big solid rock, but it’s actually made up of several parts. Some of them are constantly moving!
You can imagine that the Earth is composed of many layers, like an onion. These layers become increasingly dense as you get closer to the center of the earth. See the image below for the earth’s four main layers: mantle, mantle, outer core, and inner core.
The crust is the thin outer layer of the Earth where we live. Well, in the picture it looks thinner and thinner than other diapers, but don’t worry, we won’t accidentally fall anytime soon. The crust varies from about 5 km thick (on the ocean floor) to about 70 km thick (on the earth where we live it is called continental crust). The continental crust is made up of rocks composed mainly of silica and alumina known as “sial”.
The next layer of the Earth is called the mantle. The mantle is much thicker than the crust at a depth of nearly 3000 km. It consists of slightly different silicate rocks with more magnesium and iron.
Tectonic plates are a combination of the crust and outer mantle, also known as the lithosphere. These plates move very slowly, about a few centimeters per year. The place where the plates touch is called a defect. When the plates move and the boundaries collide, it can cause earthquakes.
Earth’s outer core is made of iron and nickel and is very hot (4400 to 5000+ degrees Celsius). So hot that iron and nickel metals are liquid! The outer core is very important to the earth because it creates the so-called magnetic field. The magnetic field generated by the outer core travels far into space and creates a protective barrier around the earth that shields us from the sun’s harmful solar wind.
The inner core of the Earth is made up of iron and nickel, just like the outer core, however, the inner core is different. The inner core is located deep in the ground, so it is under great pressure. So much pressure that even though it’s very hot, it’s still solid. The inner core is the hottest part of the Earth, and at temperatures above 5000 degrees Celsius, it is as hot as the surface of the sun.