What is the surface of the earth made up of? 

The Earth has been evolving for billions of years. Over the course of this time, it has gone through several stages of change- from the formation of its structure to creating life forms. The surface of our planet is an important part of understanding its structure, and is also a study of focus in geology and science. Although we are very closely familiar with it, because we practically live on it, we may not know what exactly lies underneath it or what it is made up of. Read on to find out what fundamentally constitutes the surface of the Earth. 

What is the surface of the Earth? 
The surface of our planet has evolved over the course of millions of years. Most of it, around 70%, is made up of water while the other 30% is made up of continental landmasses. The features that we see on the surface today are a consequence of constructive and destructive forces that have created new landforms and worn down old ones respectively. A few examples of these are volcanoes, earthquakes, chemical weathering, erosion, etc. 

Which are the fundamental layers of the Earth’s surface? 
The surface of our planet is made up of four fundamental layers. They are: the inner core, the outer core, the mantle and the crust. 

Inner core: This is the deepest layer of the Earth’s surface and is a solid metal ball with a radius of 1,220 kilometres. To put that into perspective, that is approximately three-quarters the size of the moon. Located between 6,400- 5,180 km under the surface, is made up of iron and nickel, and is extremely dense. Moreover, they typical temperature here is 5,400 degrees- which is almost as hot as the surface of the sun! Interestingly, the inner core tends to spin faster than the rest of the planet. 

Outer core: Similar to the inner core, the outer core is also mostly made up of iron and nickel, however, in the liquid form. It is located at about 5,180- 2,880 km under the Earth’s surface. The liquid is heated primarily by radioactive decay of uranium and thorium, which causes it to churn in huge currents. This leads to the generation of electrical currents which, in turn, generate the Earth’s magnetic field. 

Mantle: The mantle starts from only 30km under the Earth’s surface. It is the thickest layer at 3,000 kilometres. It is made up of iron, magnesium and silicone. It is also hot and dense with a semi-solid consistency. It’s most outermost zone is cool and rigid, as compared to the other layers. The parts of the mantle that we have been able to touch are diamonds- which form at depths above 200 km. 

Crust: The crust is the layer that we have most contact with. It is the outermost surface of the Earth. It varies a lot from place to place, and is made up of lighter elements such as silica, aluminium and oxygen. Compared to the other layers that  lie underneath it, it is extremely thin, brittle and cold.