The atmosphere is the different layers of gases that cover the celestial stars, attracted by their gravity until they stabilize around them, reaching different heights.
Its chemical composition can be very varied and, in the case of our planet Earth, contains the air we breathe and the gases that allow the existence of life.
The Earth’s atmosphere is known as Earth’s atmosphere and this article will focus on it. The Earth’s atmosphere is unique in its composition in the Solar System, since it contains the appropriate combination of gases important for life to take place on the surface of the planet.
In the atmosphere there are the conditions of temperature and pressure that allow the hydrological cycle, the ozone layer that shields the planet from solar radiation, and the friction that reduces meteorites coming from space to dust.
Characteristics Of Atmosphere
The terrestrial atmosphere is around the surface of the planet, extending from the ground up to about 10,000 kilometers around the planet, in several layers of more or less uniform gases.
75% of its gaseous mass is located in the first 11 km of elevation from the surface of the sea, and as it gains height it also gains an important measure of pressure.
The composition of the atmosphere has varied throughout the history of the planet, especially since the appearance of living beings, which consume certain gases and produce others. However, its composition is mostly nitrogen (78%) and oxygen (21%), along with other important gases such as ozone, hydrogen, carbon dioxide, argon and other noble gases. It also contains a significant presence of water vapor (H2O).
Commonly two regions are distinguished in the Earth’s atmosphere, which are:
Homosphere. Its name comes from its constant and regular composition, which occupies the first 100 km of the atmosphere from the ground. There are all the gases necessary for life in different proportions.
Heterósfera. Its name comes from the fact of being stratified in different layers of gases, which vary according to the height and pressure:
80-400 kilometers high: molecular nitrogen (N2).
400-1100 kilometers in height: atomic oxygen (O).
1100-3500 kilometers in height: helium (He).
3500-10,000 kilometers in height: hydrogen (H).
What are the layers of the atmosphere? The Earth’s atmosphere is usually divided into layers, which respond to its variation in temperature and pressure, forming a scale called atmospheric thermal gradient. These layers would be:
Troposphere. The lower layer, which ranges from the first 6 to 20 kilometers in height. It is the layer where climatic phenomena occur and the end of the layer is at a temperature of -50 ° C.
Stratosphere. It goes from 20 to 50 kilometers in height, arranged in different strata or phases of air (hence its name). In it there is the transformation of oxygen into ozone by ultraviolet rays, a process that generates heat, which is why temperatures increase in this layer (-3 ° C).
Ozonosphere. Actually it is a phase of the stratosphere, where the largest amount of ozone is produced and, therefore, is the well-known ozone layer that protects the planet from the direct impact of sunlight, absorbing more than 95% thereof.
Mesosphere It extends between 50 and 80 kilometers in height, and contains only 0.1% of the atmospheric air mass. It is the coldest area of the whole atmosphere: it reaches temperatures of up to -80 ° C.
Ionosphere. Also called thermosphere, it goes from 90 to 800 kilometers, and in it the temperature increases with altitude, according to the presence of solar rays. Temperatures of 1500 ° C and even higher have been recorded in it.
Exosphere The outer layer of the atmosphere, which starts at 800 kilometers and ends at 10,000. There the atoms escape into space, and it is the transit zone between our planet and outer space.
5. Greenhouse effect
It is known as greenhouse effect to the presence of atmospheric gases such as carbon dioxide that form a dense layer in the atmosphere and prevent the escape of terrestrial heat (similar to the walls of a greenhouse). This effect is vital for the preservation of terrestrial heat, indispensable for life.
What is the atmosphere for? The atmosphere fulfills vital functions for the stability of the planet, as we have said. Not only allows the perpetuation of biochemical cycles to supply the essential gases, but also prevents the escape of heat into outer space, shields us against meteorites (friction with the air disintegrates them) and solar radiation. Without it we would be exposed to the spatial elements and dramatic temperature variations between day and night.
The magnetosphere is the name given to the region of the atmosphere in which the magnetic field of the planet is noted. This is generated by its rotation movement and its heart of cast iron, which acts like a dynamo. This field is also vital to prevent the entry of solar wind and other forms of electromagnetic radiation to our planet. When this occurs, the so-called “auroras” occur.
8. Space travels
Overcoming the resistance of the atmosphere is one of the main challenges of space travel, as well as to overcome gravity in a sustained manner. The friction suffered by a space shuttle during its takeoff in the initial layers of the atmosphere can generate heating, deviation of the trajectory and even breakage of materials. On the other hand, once in the outer layers, the low density of gaseous material will allow the displacement in a much gentler way.
The origin of the atmosphere is usually attributed to the presence of gases originating in the early stages of the Solar System, which were trapped in the gravity of the planet, as well as the degassing of the Earth’s crust as it cooled. To that must be added the ice and water coming from the impact of comets on Earth and then the appearance of the gases proper to organic life.
Atmospheric pollution occurs mainly in the form of gases, which not only enhance the greenhouse effect but also corrode the ozone layer, allowing the entry of solar radiation and increasing the temperature of the planet. To this must be added the suspension of toxic particles in the lower layers of the atmosphere, which can lead to acid rain.