The Fascinating Structure of Our Planet

From the outside, the Earth may look like a giant marble with swirls of green and blue intertwining, but in reality, it is composed of many layers hidden beneath the rocky surface that we walk on. The Earth is made of 4 main layers: the crust, mantle, outer core, and inner core. Each layer has its features that define its distinct role in preserving life on earth.

Crust: The crust is the outermost layer of the earth and is where we take part in our daily activities. Although it is relatively thin in comparison to the other layers, the earth’s crust can be as deep as 70 km on land (continental crust) and 5 km deep in the seafloor (oceanic crust). The crust is mainly made up of a combination of rocks and minerals, including elements such as silicon and aluminum.

The crust is also divided into plates that float on top of the mantle, the next layer of earth. These pieces of crust are constantly moving and are what cause mountains, volcanoes, and other geological features to form.

Mantle: The mantle is the layer under the crust. It is significantly deeper than the crust with a depth of almost 2,890 km. The mantle is mainly composed of molten rock rich in magnesium and iron. Immense amounts of heat from the core, the innermost layer of the earth, cause this liquid rock to rise to the mantle, where it cools and sinks back down to the core. This constant flow of molten rock across the mantle and core is called convection and is what causes the plates on the crust that float on the mantle to slowly move over time.

Core: At the center of the earth lays the core, the innermost layer of the earth. The core, in actuality, has two separate layers: the outer core and inner core. The outer core is approximately 2,180 km deep and is primarily composed of nickel and iron. The core is very hot, varying in temperatures from 4400° Celsius to over 5000° Celsius. In fact, the nickel and iron found here are always in a liquid state because of such high temperatures. Additionally, the outer layer creates a magnetic field around the earth, which acts as a protective shield that blocks the sun's damaging winds from hitting the surface of the earth. On the other hand, the inner core, though very similar to the outer core in terms of composition, has a very distinct high heat and pressure system that no other layer has. In fact, the inner core is the hottest layer of the earth with temperatures over 5000° Celsius, which is almost as hot as the surface of the sun. Despite this, the iron and nickel are in a solid state of matter rather than liquid because of the layer’s extremely high pressure system.

So the next time you step outside to go for a walk, remember that underneath, the earth isn’t as solid as you once thought it was.

Internal structure of the Earth

Picture Source: usgs.gov