Layers of earth: What is inside the earth?
Basically, there are three layers of the Earth.
1. Core, which is the inner layer and is divided into the inner core and outer core
2. The mantle is the middle layer.
3. The Crust top layer or outer layer.
At the beginning of the creation of the solar system, the Earth was a hot gas ball. It is located at the third position from the sun. The surface of the Earth then gradually cooled as a result of billions of years of heat radiation.
This results in the accumulation of heavy metals in the center and light matter on the surface of the Earth, forming distinct layers of the Earth. Pressure and heat gradually increase from the surface of the Earth to the interior of the Earth. Thus, the temperature of the Earth’s interior is very high. Hence, the elements here are in a liquid or gaseous state. There are mainly three layers of Earth.
Crust
The crust is the Earth's thin, solid, and brittle outermost layer.
It covers the interior of the Earth like the shell of an egg.
All life, oceans, and continents exist on this layer.
This layer is also called the lithosphere. The word “lithos” means rocks, as it is made up of different rocks, so it is called the lithosphere.
Thickness: It is the thinnest layer, ranging from about 5 km (3 miles) under the oceans to 70 km (44 miles) under large mountain ranges.
Composition:The crust is made up Primarily of silicate rock which are rich in silicon and oxygen.
Oceanic Crust is Denser and typically composed of basalt.
Continental Crust is Less dense and is mainly composed of granite.
Role in Tectonics: The crust and the very top layer of the mantle form the lithosphere, which is broken into the rigid tectonic plates that move across the planet.
Next layer after the thin crust comes the mantle
The Mantle
It is the layer directly beneath the crust and makes up the vast majority (about 84%) of the Earth's total volume.
Composition: Dense silicate rock rich in iron and magnesium.
Physical State: Although mostly solid, the mantle is divided into sections with varying behaviors:
Upper Mantle (Asthenosphere): A weaker, more ductile layer where rock is semi-molten and can flow very slowly over geological timescales.
Convection: Slow, churning movements of heat (known as convection currents) within the mantle drive the movement of the overlying tectonic plates.
The Core
The core is the hot, dense, metallic center of the Earth.
It is divided into two distinct parts: the liquid outer core and the solid inner core.
It is composed mainly of iron and nickel.
A. The Outer Core
The outer core is made up of liquid metal alloy
Thickness: About 2,300 km (1,400 miles) thick.
Significance: The liquid iron in the outer layer of the core is in constant movement. This circulating movement of this liquid iron generates electrical currents. Which in turn creates the Earth’s magnetic field (the geodynamo). This field protects the Earth from harmful solar radiation.
B. The Inner Core
State: Solid ball of iron and nickel.
Radius: Approximately 1,220 km (760 miles).
Significance: This is the hottest part of the Earth, but despite of high temperatures, the immense pressure at the planet's center is so great that it prevents the iron from melting, forcing it into a solid state.
In summary, the journey to the center of the Earth takes you through solid rock (Crust), semi-solid rock (Mantle), liquid metal (Outer Core), and finally, solid metal (Inner Core).