What is the name of the air envelope of the Earth? The structure, physical properties and composition of the atmosphere

It's not a secret for anyone that the air is an extremely important part of the biosphere. After all, it is his unique composition that provides an opportunity for life on the planet. But what is the name of the air envelope of the Earth? What is it and what is unique? What is its chemical composition and physical properties? These questions are of interest to many.

What is the name of the air envelope of the Earth?

It is known that life on Earth is possible largely due to the unique composition of the air. And the gas shell is called the atmosphere. This part of the biosphere completely surrounds the planet and is held around the celestial body due to gravity.

Naturally, this shell has certain chemical and physical properties. As for the borders, it is impossible to clearly carry them out. Closer to the earth's surface, the atmosphere is in contact with the lithosphere and the hydrosphere. But to determine where the gas shell ends and the open space begins is extremely difficult. Today, it is customary to conduct a border at an altitude of 100 km, where the so-called Karman line is located - in this region aeronautics is no longer possible.

The atmosphere is the air envelope of the Earth, the value of which can not be overestimated. After all, do not forget that virtually all celestial bodies are under the influence of ionizing and ultraviolet radiation, which are harmful to living organisms. It is in the gas shell that these rays are neutralized.

Theory of the origin of the atmosphere

In fact, many people are wondering how the Earth's air shell was formed. The answer to this question can hardly be exact, since for today there are several different theories about the origin of the atmosphere.

According to the most common hypothesis, the primary atmosphere was formed four billion years ago from light gases, namely helium and hydrogen, which were captured from interplanetary space. Due to high volcanic activity, a secondary gas shell was created in the future, which was saturated with carbon dioxide, water vapor and ammonia.

Tertiary atmosphere was formed due to many processes - chemical reactions (for example, lightning discharges), ultraviolet action, leakage of helium and hydrogen back into interplanetary space.

The chemical composition of the atmosphere

Now, when it became clear what is called the air shell of the Earth, it is worth considering its chemical composition, which is considered unique. Immediately it should be noted that only the lower layers of the atmosphere are saturated with different gases. In particular, in the air that we inhale, nitrogen predominates (78.08%). The oxygen level is 20.95%. These are the two main gases.

In addition, the air envelope of the Earth includes other components - carbon dioxide, hydrogen, argon, helium, xenon, methane, sulfur and nitrogen oxides, ozone, ammonia.

The structure of the air envelope of the Earth

The atmosphere is divided into several main layers, each of which has different physical and chemical characteristics.

• The troposphere is the closest layer to the surface of the earth. It is here that 80% of all air is concentrated. And it is here that the life of a person is possible. By the way, almost all the atmospheric water (90%) is concentrated in this layer. Here, clouds and precipitation form. The troposphere extends for 18 km from the surface of the earth. With rising up, the temperature is decreasing.
• The stratosphere (12-50 km) is a layer that is considered the most tranquil part of the atmosphere. It is here that the ozone layer is located.
• The thermosphere is part of the atmosphere, the upper boundary of which is approximately 700-800 km. Here, the temperature with the rise begins to rise sharply, and in some areas is about 1200 degrees Celsius. Within the boundaries of this layer is the so-called ionosphere, where air is highly ionized under the influence of solar radiation.
• The exosphere is a scattering zone, which at an altitude of 3000 km passes into outer space. The air here is saturated with light gases, in particular hydrogen and helium.

Basic physical characteristics of the atmosphere

Of course, the physical properties of air are extremely important. For example, knowing them, you can determine how the atmosphere affects the human or any other living organism. In addition, the measurement of physical parameters is simply necessary to determine the optimal characteristics of aircraft, aircraft, etc. In particular, the following physical indicators are taken into account:

• The air temperature is measured by the following formula: t1 = t - 6.5H (here t is the air temperature at the earth's surface, and H is the altitude).
• The density of air is the mass of air per cubic meter.
• Pressure that can be measured both in Pascals and in atmospheres.
• Humidity shows the amount of water in a unit of air. It should be noted that zero humidity is possible only in laboratory conditions. The higher this figure, the lower the density of air, and vice versa.

By the way, science, which answers questions about what is called the air envelope of the Earth, what are its properties and characteristics, is meteorology. Scientists are not only studying the atmosphere, but also monitoring its constant changes that affect weather and climate.

Atmosphere and its meaning

The importance of the gas envelope of the Earth is very difficult to overestimate. After all, just a few minutes without air lead to loss of consciousness, hypoxia and irreversible brain damage. Only thanks to the amazing composition of the atmosphere, living organisms can receive the oxygen they need.

In addition, the air envelope protects the planet's surface from harmful cosmic radiation. At the same time, enough ultraviolet rays pass through the atmosphere, which warm the Earth. Scientists say that reducing ultraviolet light will lead to a decrease in overall temperature and freezing. In addition, under the influence of sunlight (in a reasonable amount), human skin tissue forms vitamin D.

The ozone layer and its meaning

In the stratosphere, at an altitude of 12-50 km from the surface of the earth, there is an ozone layer. This part of the atmosphere was discovered in 1912 by French scientists Sh. Fabri and A. Buisson.

Ozone is a colorless gas with a sharp characteristic odor. It consists of three oxygen atoms. It is this part of the gas shell that protects the earth's surface from dangerous cosmic radiation.

Unfortunately, in connection with technical and industrial progress, the amount of harmful substances in the air envelope of the Earth has increased, which gradually destroy the ozone layer. The so-called ozone holes are an extremely dangerous problem.

Atmospheric pollution: the greenhouse effect and acid rain

Unfortunately, the constant air pollution, which is associated mainly with the developed industry, leads to a mass of deterioration. Such dangerous changes include the so-called greenhouse effect. The fact is that terrestrial bodies emit waves of predominantly infrared spectrum - they can not always penetrate the atmosphere. An increase in the concentration of greenhouse gases that absorb infrared radiation (water vapor, carbon dioxide), leads to an increase in the overall temperature in the lower layers of the atmosphere, which, accordingly, affects the climate.

Acid rain - another result of industrial pollution of the Earth's air envelope. Sulfur and nitrogen oxides, which are released into the air by thermal power plants, cars, metallurgical plants and some other enterprises, can react with water vapor of the atmosphere - under the influence of solar radiation, acids are formed which fall out together with other precipitates.