Meaning of Atmosphere Layers
The layer of air that surrounds the Earth, the atmosphere , when it was formed, was made up of gases that participated, together with cosmic dust, in the origin of the solar system.
The changes that have taken place in the atmosphere, in the last 4.6 billion years of our planet’s existence, have given way to the atmosphere that we know today.
This layer of millions and millions of liters of air, due to the force of the Earth’s gravity, which attracts everything close to it towards the center, keeps all that air around our planet.
Its thickness is not precisely defined, and the composition and concentration of gases are not very uniform at high altitudes. The temperature varies in the different layers of the atmosphere . The best known are:
Troposphere
It is the part in which we live and which reaches up to approximately 15 km. It is dense, containing 75% of the gases in the entire atmosphere, water vapor and dust. In this layer, thunder, clouds, winds and all the main atmospheric phenomena are formed.
The temperature in the troposphere decreases with altitude, reaching -55 ° C in the highest regions.
Stratosphere
It comprises the layer of air that is located between 15 km and 50 km in height. The temperature rises again (17 ° C) and the air is very thin.
In this layer there is the presence of winds with very high speeds, reaching 400 or 500 km / h. The gas that makes up the stratosphere is very rarefied and, between 30 km and 40 km, there is one in the layer of a special gas formed by three oxygen atoms (O3): ozone .
Ozone is present throughout the atmosphere, but it appears in greater concentration in the upper troposphere and the stratosphere.
Mesosphere
It extends to a height of 85 km. In it the air is very thin and the temperature is very low, reaching –120 ° C.
In this layer it is possible to observe the meteorites that fall on Earth and become incandescent because they are rubbed against the gases so they become visible and are known as falling stars.
Ionosphere or Thermosphere
It is a layer that extends from 85 km to 640 km and is characterized by the presence of particles called ions.
It is of great importance for radiocommunication, because in this layer, the waves are reflected, making it possible to communicate over great distances.
In the higher regions of this layer, satellites are located for the transmission of television and telephony waves, the so-called artificial satellites.
The gases that make up the ionosphere are oxygen, hydrogen and nitrogen. An interesting phenomenon that occurs in this layer is the aurora borealis , which happens when particles from the sun’s rays, in contact with atmospheric gases, produce, at night, beautiful colored shapes.
The word thermosphere is formed by the prefix term – which indicates “heat”. This shows that the sun’s energy increases its temperature.
Exosphere
It is the outermost layer of the atmosphere, extending between 900 and 1,000 km and in it the air is very thin. There are the presence of oxygen and nitrogen. Atmospheric pressure is practically zero and is the limit with outer space.
