Layers of the EARTH and their characteristics

Our planet Earth is too big to be studied in all its structure and composition, so in order to study the structure of our planet, its composition and characteristics the simplest thing is to divide it by large layers or spheres. In turn, these huge spheres are subdivided into other layers. In this lesson from a PROFESSOR we are going to see what are the Earth's layers and their characteristics. If this topic interests you, join us in the next lesson!

The layers of the Earth can be divided into 4 layers or spheres:

• geosphere (also known as the lithosphere)
• Hydrosphere
• Biosphere
• Atmosphere

None of these layers is independent of one another, but rather are interconnected and dependent each other. Among them they differ in their composition and characteristics, such as their temperature, which is higher the closer it gets to the inner core of the Earth, due to the increase in pressure.

The structure and composition of these four terrestrial spheres is studied by geology. Knowing this is important to find out the evolution of our planet. It also studies the natural resources and processes that impact the earth's surface.

We are going to analyze the layers of the Earth and their characteristics, focusing on the atmosphere, since it constitutes the largest layer of the planet. It reaches up to 10 thousand km thick and is a fundamentally gaseous layer. The main gases in its composition are nitrogen, oxygen and to a lesser extent ozone, carbon dioxide and water vapor.

We can divide, in turn, the atmosphere in the following layers:

• Troposphere: This is the lower layer of the atmosphere. It is in contact with the surface of the earth and climatic and meteorological phenomena take place there, since clouds, winds and water vapor are concentrated there. It is made up of nitrogen, oxygen and water vapor. It reaches an approximate height of 10 km and as it moves away from the surface of the earth, the pressure and density of the air decrease.
• Stratosphere: this layer is made up of inorganic elements, such as sulfuric acid, ozone, nitric acid, nitrogen oxide or halogenated compounds. It is a layer that presents a cold and heavy air. The ozone layer is located in its outer part and is the one that acts as a filter or shield against the ultraviolet radiation of the sun that was not absorbed in the thermosphere.
• mesosphere: This layer protects the earth from the impact of meteorites and asteroids. It is formed by a mixture of different gases, so it does not present a stratification like other layers of the atmosphere.
• ionosphere or thermosphere: This tasting is made up of gases from different chemical ionization processes, such as carbon dioxide, oxygen, or nitrogen, which is why it is also called the ionosphere. This layer is very important, since it is the one that absorbs most of the sun's radiation, such as ultraviolet radiation.
• exosphere: This is the transition layer between the atmosphere and the outer space that surrounds it, where neither gases nor gravity exist. It is the least dense layer of the atmosphere and is made up of helium and hydrogen. In this layer are several of the artificial satellites that orbit the earth.

This layer extends from 3 meters below ground to 30 meters above and it is made up of all the living beings that inhabit the planet, such as animals, unicellular organisms or plants.

This extension was proposed because it is in it where inhabit most living organisms. In oceans and ares, most aquatic organisms live from the surface to approximately 200 meters deep, where light is already scarce and pressure is very high.

However, there are also living organisms that live outside these ranges. For example, some birds fly in some situations up to 7000 meters above sea level, some marine species have been found living at a depth of 6000 meters in the mariana trench or microorganisms that live far beyond these ranges, in conditions really extreme.

we can split the whole of the biosphere in different biomes, which are the habitats where species of plants and animals live together. Examples of biomes are deserts, with their sand, cacti and lizards, or coral reefs.

The hydrosphere is not a layer defined as such, but the field of geology is known as the hydrosphere to the set of deposits and circulating water of water that exists on the surface of our planet earth, both on the continents and outside they. This covers seas, lakes, groundwater, rivers, ice, snow and oceans. These liquid water deposits occur only on planet Earth, which is the only planet in the system that presents them (that we know at the moment), which makes it conducive to life as the meet each other

Two thirds of the surface of our planet Eartha is covered by water, which makes a total of approximately 1400 trillion liters. However, this distribution is not equitable among all the loops of water that exist, but its distribution occurs in the following way.

• oceans: the oceans represent the largest part of the earth's surface, specifically it is 93.96% of the total.
• Groundwater: These are the waters that are found below the surface of the earth, in the soil and in the subsoil, between the interstices of the rocks, such as in aquifers. In total they represent approximately 4.12% of the total.
• Inland waters and glaciers: represents 1.65% of the total.
• reservoirs and lakes: they are a minority part of the hydrosphere. They represent only 0.019% of the total.
• atmospheric humidity: only represents 0.001% of the total water.
• river water: they represent 0.0001% of the total.

Depending on where that water is located and its state, its ability to renew itself and rate of change will vary. In its water vapor state, it is completely renewed about 34 times per year, and completely leaves the atmosphere in about 10 days. In contrast, the water in the oceans takes about 3,700 years to completely renew itself. The hydrosphere is in continuous movement and change, thus creating a water cycle or water cycle on earth.

In this cycle, the terrestrial water evaporates, precipitates and freezes periodically, depending on the pressure and temperature of each region. This cycle is a fundamental part of life on this planet: the precipitation of water wets the soil and encourages the rivers and the loops of water, which evaporate and keep the air humid, which returns to precipitate, and so on cyclically.

In the coldest regions of the planet, such as Antarctica, water solidifies as ice. In the state of gas or water vapor, water is found in the loops of warm or thermal air that emits steam, in the highest clouds (those that reach the atmosphere) and in fog.

We ended up getting to know the layers of the Earth and their characteristics by talking about the geosphere. It encompasses the layers that make up the solid part of the planet.

Like other planets, Earth is made up of different types of rock materials with different dynamics between them. Many of these rocky materials have been formed during convulsive geological stages of volcanic activity. Some of these rocks are dated to about 4.4 billion years ago.

The geosphere is studied by geologists and other specialists by exploring the soil, especially in those places where the lower strata may outcrop due to different terrain features. Many of these observations are not measured directly, but through approximation formulas.

Its structure can be studied from a chemical or geological point of view. From a chemical point of view, the geosphere is divided into three hats, which from outside to inside are:

• Cortex: the crust extends from the surface to 35 km deep and is the rock stratum surface on which life develops and with a relatively thin thickness that reaches a density average of 3 g/cm³. This layer also includes seabeds and deep depressions. It is formed mainly by silicate rocks of different elements.
• Mantle: It extends from 35 to 2,890 km deep. It is the thickest layer and is made up of siliceous rocks, with a higher iron content than the crust. The greater the depth of the mantle, the greater the pressure and temperature, to reach a semi-solid state that allows the movement of the tectonic plates in earthquakes. Due to pressure, the upper layer of the mantle has more movement and is less viscous than the lower layer.
• Core: It extends from 2,890 to 6,371 km deep. It is the innermost part of the planet and the densest materials are located there. We can divide it in turn into the outer core (up to 5,150 km) and the inner core (up to 6,371 km) and is made up of up to 80% iron and nickel and other minor materials, such as lead.

From a geological point of view, it can be divided into the lithosphere (up to 100 km deep) which is the most solid part, the asthenosphere (up to 400 km deep). depth) with more ductile materials, the mesosphere (up to 2890 km) which corresponds to the mantle and the endosphere (up to 6371 km) which corresponds to the of the core.