What are the layers of the Earth?

Do you know what the layers of the Earth are ? In this article you will check this answer and more. Follow us!

The planet we live in is the third closest planet to the Sun, and is now recognized as the only planet capable of harboring living beings and their most varied forms. Scientists claim that the Earth has appeared about 4.5 billion years ago and since then has been gradually inhabited by numerous species of animals, plants, fungi, microorganisms and humans.

The interactions between living things (biotic factors) and non-living beings (abiotic factors) that occur on Earth, is studied by Ecology. Ecology is a branch of biology that has become more and more prominent, because the environmental changes brought about by human action will only be reduced as the structure and functioning of ecosystems are known.

The broadest level studied by ecology is the biosphere. The term "biosphere" was created by similarity to those used to designate layers or spheres related to the Earth's abiotic components, which are:

1- Atmosphere ( atmos = gas) : layer or sphere of the Earth formed by air; 
2 - Hydrosphere (hydro = water) : layer or sphere of the Earth formed by water; 
3 - Lithosphere (litho = stone) : layer or sphere of the Earth formed by rocks and soils. This layer surrounds and protects the Earth's crust, which is the outermost and most superficial layer of the planet.

The Earth's Crust is the most superficial layer of Earth (Photo: depositphotos)

Biosphere

The biosphere , like the other "spheres", is not a homogeneous layer , because the environmental conditions of our planet vary from one region to another. The limits of the biosphere are well defined according to records that indicate the presence of living beings. These boundaries range from approximately 11,000 meters deep in the oceans to about 7,000 meters in the atmosphere.

Environmental conditions are very important in the distribution of living things. In places where such conditions are more favorable, the diversity of living forms is greater, the opposite occurring when conditions are not favorable. One of the main factors that interfere in these conditions is the climate of the different regions, which is influenced by latitude, longitude, altitude and other factors.

The biosphere is the region of the Earth where the existence of life is possible. It is formed by the set of ecosystems , occupies the space in the atmosphere and goes to the ocean depths.

The three inner layers of Earth

As we mentioned, there are three major layers that make up the Earth: the atmosphere, the hydrosphere, and the lithosphere, but as we look at the planet itself, we can also consider three layers forming the interior of the Earth: Earth's crust, mantle, and core.

Earth's crust

The earth's crust is protected externally by the lithosphere. It is the most superficial layer of the planet, formed by rocks and minerals, that is, it is the solid layer of the Earth. Three types of rocks make up the earth's crust: magmatic or igneous, metamorphic and sedimentary.

Cloak

It is the layer located between the Earth's crust and the nucleus . The mantle is divided into two parts, one inner and one outer. The upper (outer) mantle is less hot than the lower mantle (inner) and more doughy as well. The mantle reaches very high temperatures , reaching approximately 2,000 ºC. It is constantly moving, slowly, exerting pressure on the earth's crust. The mantle is responsible for causing earthquakes, volcanism and the movement of tectonic plates.

Core

It is the innermost layer of the planet, and can be subdivided into inner and outer nuclei. The outer core is composed of liquid iron and nickel, the inner core by silicon, nickel and solid iron. The core corresponds to a third of the mass of the Earth and can reach a temperature of approximately 6,000 ºC, that is, it is the warmest layer that exists.

The layers of the atmosphere

The atmosphere can be divided into five main layers : the troposphere, the stratosphere, the mesosphere, the thermosphere and the exosphere. The limit of each of them is defined by the abrupt change of the average temperature.

The atmosphere is fundamental to the biosphere, as it contains essential gases for life, and prevents the Earth from losing heat , acting as a "blanket" or as a greenhouse. This is why we talk about greenhouse effect or coverage effect of the atmosphere. The main components of the atmosphere that contribute to the greenhouse effect are oxygen gas, methane gas and water vapor.

Troposphere

The troposphere is the closest layer to the Earth's surface and the one that presents most of the gas molecules in the atmosphere. This is where we find the proportions of approximately 78% of nitrogen gas, 21% of oxygen gas, 0.03% of carbon dioxide and 0.3% of water vapor. There are, however, several other gases which, although they appear in very small proportion, can have enormous environmental importance. This is the case of nitrous oxide, nitrogen dioxide, ozone and methane.

It is in the troposphere that the main climatic phenomena occur . This layer is characterized by the decrease in temperature as a function of altitude.

Stratosphere

Above the troposphere is the stratosphere, a layer rich in ozone , a gas formed by the breakdown of oxygen gas molecules by radiant energy and subsequent rearrangement of atoms into ozone molecules. It is the main gas responsible for the increase in temperature that occurs in this layer as the altitude increases. Ozone absorbs most of the sun's ultraviolet radiation , which is converted to thermal energy.

Mesosphere

The third layer of the atmosphere is the mesosphere, characterized by the decrease in temperature as a function of altitude.

Thermosphere

In the fourth layer is the thermosphere, where there is a rise in temperature with increasing altitude, because few molecules present there absorb high energy solar radiation, and its conversion into thermal energy.

Exosphere

It is the furthest layer of Earth , starting about 500 kilometers above ground surface. In this layer the air is considered rarefied and the main gases are: hydrogen, helium, carbon dioxide and atomic oxygen.