Everyone who has flown on an airplane is used to this kind of message: "our flight is at an altitude of 10,000 m, the temperature overboard is 50 ° C." It seems nothing special. The farther from the surface of the Earth heated by the Sun, the colder. Many people think that the decrease in temperature with height goes on continuously and gradually the temperature drops, approaching the temperature of space. By the way, scientists thought so until the end of the 19th century.

Let's take a closer look at the distribution of air temperature over the Earth. The atmosphere is divided into several layers, which primarily reflect the nature of temperature changes.

The lower layer of the atmosphere is called troposphere, which means "sphere of rotation". All changes in weather and climate are the result of physical processes occurring precisely in this layer. The upper boundary of this layer is located where the decrease in temperature with height is replaced by its increase - approximately at an altitude of 15-16 km above the equator and 7-8 km above the poles. Like the Earth itself, the atmosphere under the influence of the rotation of our planet is also somewhat flattened over the poles and swells over the equator. However, this effect is much stronger in the atmosphere than in the solid shell of the Earth. In the direction from the Earth's surface to the upper boundary of the troposphere, the air temperature drops. Above the equator, the minimum air temperature is about -62 ° C, and above the poles about -45 ° C. In temperate latitudes, more than 75% of the mass of the atmosphere is in the troposphere. In the tropics, about 90% is within the troposphere masses of the atmosphere.

In 1899, a minimum was found in the vertical temperature profile at a certain altitude, and then the temperature slightly increased. The beginning of this increase means the transition to the next layer of the atmosphere - to stratosphere, which means "layer sphere". The term stratosphere means and reflects the former idea of ​​​​the uniqueness of the layer lying above the troposphere. The stratosphere extends to a height of about 50 km above the earth's surface. Its feature is, in particular, a sharp increase in air temperature. This increase in temperature is explained ozone formation reaction - one of the main chemical reactions occurring in the atmosphere.

The bulk of the ozone is concentrated at altitudes of about 25 km, but in general the ozone layer is a shell strongly stretched along the height, covering almost the entire stratosphere. The interaction of oxygen with ultraviolet rays is one of the favorable processes in the earth's atmosphere that contribute to the maintenance of life on earth. The absorption of this energy by ozone prevents its excessive flow to the earth's surface, where exactly such a level of energy is created that is suitable for the existence of terrestrial life forms. The ozonosphere absorbs some of the radiant energy passing through the atmosphere. As a result, a vertical air temperature gradient of approximately 0.62 ° C per 100 m is established in the ozonosphere, i.e., the temperature rises with height up to the upper limit of the stratosphere - the stratopause (50 km), reaching, according to some data, 0 ° C.

At altitudes from 50 to 80 km there is a layer of the atmosphere called mesosphere. The word "mesosphere" means "intermediate sphere", here the air temperature continues to decrease with height. Above the mesosphere, in a layer called thermosphere, the temperature rises again with altitude up to about 1000°C, and then drops very quickly to -96°C. However, it does not fall indefinitely, then the temperature rises again.

Thermosphere is the first layer ionosphere. Unlike the previously mentioned layers, the ionosphere is not distinguished by temperature. The ionosphere is a region of an electrical nature that makes many types of radio communications possible. The ionosphere is divided into several layers, designating them with the letters D, E, F1 and F2. These layers also have special names. The division into layers is caused by several reasons, among which the most important is the unequal influence of the layers on the passage of radio waves. The lowest layer, D, mainly absorbs radio waves and thus prevents their further propagation. The best studied layer E is located at an altitude of about 100 km above the earth's surface. It is also called the Kennelly-Heaviside layer after the names of the American and English scientists who simultaneously and independently discovered it. Layer E, like a giant mirror, reflects radio waves. Thanks to this layer, long radio waves travel farther distances than would be expected if they propagated only in a straight line, without being reflected from the E layer. The F layer also has similar properties. It is also called the Appleton layer. Together with the Kennelly-Heaviside layer, it reflects radio waves to terrestrial radio stations. Such reflection can occur at various angles. The Appleton layer is located at an altitude of about 240 km.

The outermost region of the atmosphere, the second layer of the ionosphere, is often called exosphere. This term indicates the existence of the outskirts of space near the Earth. It is difficult to determine exactly where the atmosphere ends and space begins, since the density of atmospheric gases gradually decreases with height and the atmosphere itself gradually turns into an almost vacuum, in which only individual molecules meet. Already at an altitude of about 320 km, the density of the atmosphere is so low that molecules can travel more than 1 km without colliding with each other. The outermost part of the atmosphere serves as its upper boundary, which is located at altitudes from 480 to 960 km.

More information about the processes in the atmosphere can be found on the website "Earth climate"

The exact size of the atmosphere is unknown, since its upper boundary is not clearly visible. However, the structure of the atmosphere has been studied enough so that everyone can get an idea of ​​​​how the gaseous shell of our planet is arranged.

Atmospheric physics scientists define it as the area around the Earth that rotates with the planet. The FAI gives the following definition:

• The boundary between space and the atmosphere runs along the Karman line. This line, according to the definition of the same organization, is the height above sea level, located at an altitude of 100 km.

Everything above this line is outer space. The atmosphere gradually passes into interplanetary space, which is why there are different ideas about its size.

With the lower boundary of the atmosphere, everything is much simpler - it passes through the surface of the earth's crust and the water surface of the Earth - the hydrosphere. At the same time, the boundary, one might say, merges with the earth and water surfaces, since particles of air are also dissolved there.

What layers of the atmosphere are included in the size of the Earth

Interesting fact: in winter it is lower, in summer it is higher.

It is in this layer that turbulence, anticyclones and cyclones arise, clouds form. It is this sphere that is responsible for the formation of the weather; approximately 80% of all air masses are located in it.

The tropopause is the layer in which temperature does not decrease with height. Above the tropopause, at an altitude above 11 and up to 50 km, is the stratosphere. The stratosphere contains a layer of ozone, which is known to protect the planet from ultraviolet rays. The air in this layer is rarefied, which explains the characteristic purple hue of the sky. The speed of air currents here can reach 300 km/h. Between the stratosphere and the mesosphere is the stratopause - the boundary sphere, in which the temperature maximum takes place.

The next layer is the mesosphere. It extends to heights of 85-90 kilometers. The color of the sky in the mesosphere is black, so the stars can be observed even in the morning and afternoon. The most complex photochemical processes take place there, during which atmospheric glow occurs.

Between the mesosphere and the next layer, the thermosphere, is the mesopause. It is defined as a transition layer in which a temperature minimum is observed. Above, at an altitude of 100 kilometers above sea level, is the Karman line. Above this line are the thermosphere (altitude limit 800 km) and the exosphere, which is also called the "dispersion zone". At an altitude of about 2-3 thousand kilometers, it passes into the near space vacuum.

Given that the upper layer of the atmosphere is not clearly visible, it is impossible to calculate its exact size. In addition, there are organizations in different countries with different opinions on this matter. It should be noted that Karman line can be considered the boundary of the earth's atmosphere only conditionally, since different sources use different boundary marks. So, in some sources you can find information that the upper limit passes at an altitude of 2500-3000 km.

NASA uses the 122 kilometer mark for calculations. Not so long ago, experiments were carried out that clarified the border as located at around 118 km.

The Earth's atmosphere is heterogeneous: different air densities and pressures are observed at different heights, temperature and gas composition change. Based on the behavior of the ambient temperature (i.e., the temperature rises with height or decreases), the following layers are distinguished in it: troposphere, stratosphere, mesosphere, thermosphere and exosphere. The boundaries between the layers are called pauses: there are 4 of them, because. the upper boundary of the exosphere is very blurred and often refers to the near space. The general structure of the atmosphere can be found in the attached diagram.

Fig.1 The structure of the Earth's atmosphere. Credit: website

The lowest atmospheric layer is the troposphere, the upper boundary of which, called the tropopause, varies depending on the geographical latitude and ranges from 8 km. in polar up to 20 km. in tropical latitudes. In middle or temperate latitudes, its upper boundary lies at altitudes of 10-12 km. During the year, the upper boundary of the troposphere experiences fluctuations depending on the influx of solar radiation. So, as a result of sounding at the South Pole of the Earth by the US meteorological service, it was revealed that from March to August or September there is a steady cooling of the troposphere, as a result of which, for a short period in August or September, its border rises to 11.5 km. Then, between September and December, it drops rapidly and reaches its lowest position - 7.5 km, after which its height remains practically unchanged until March. Those. The troposphere is at its thickest in summer and at its thinnest in winter.

It should be noted that in addition to seasonal variations, there are also daily fluctuations in the height of the tropopause. Also, its position is influenced by cyclones and anticyclones: in the first, it descends, because. the pressure in them is lower than in the surrounding air, and secondly, it rises accordingly.

The troposphere contains up to 90% of the total mass of the earth's air and 9/10 of all water vapor. Turbulence is highly developed here, especially in the near-surface and highest layers, clouds of all tiers develop, cyclones and anticyclones form. And due to the accumulation of greenhouse gases (carbon dioxide, methane, water vapor) of the sun's rays reflected from the Earth's surface, the greenhouse effect develops.

The greenhouse effect is associated with a decrease in air temperature in the troposphere with height (because the heated Earth gives off more heat to the surface layers). The average vertical gradient is 0.65°/100 m (i.e. the air temperature drops by 0.65° C for every 100 meters you rise). So if at the Earth's surface near the equator the average annual air temperature is + 26 °, then at the upper limit -70 °. The temperature in the tropopause region above the North Pole varies throughout the year from -45° in summer to -65° in winter.

As the altitude increases, the air pressure also decreases, amounting to only 12-20% of the near-surface level near the upper troposphere.

On the border of the troposphere and the overlying layer of the stratosphere lies the tropopause layer, 1-2 km thick. The air layer in which the vertical gradient decreases to 0.2°/100 m versus 0.65°/100 m in the underlying regions of the troposphere is usually taken as the lower boundaries of the tropopause.

Within the tropopause, air flows of a strictly defined direction are observed, called high-altitude jet streams or "jet streams", formed under the influence of the Earth's rotation around its axis and heating of the atmosphere with the participation of solar radiation. Currents are observed at the boundaries of zones with significant temperature differences. There are several centers of localization of these currents, for example, arctic, subtropical, subpolar and others. Knowing the localization of jet streams is very important for meteorology and aviation: the first uses streams for more accurate weather forecasting, the second for building aircraft flight routes, because At the flow boundaries there are strong turbulent vortices, similar to small whirlpools, called "clear sky turbulence" due to the absence of clouds at these altitudes.

Under the influence of high-altitude jet currents, ruptures often form in the tropopause, and at times it disappears altogether, though then it forms again. This is especially often observed in subtropical latitudes over which a powerful subtropical high-altitude current dominates. In addition, the difference in the layers of the tropopause in terms of ambient air temperature leads to the formation of breaks. For example, a wide gap exists between the warm and low polar tropopause and the high and cold tropopause of tropical latitudes. Recently, a layer of the tropopause of temperate latitudes has also been distinguished, which has breaks with the previous two layers: polar and tropical.

The second layer of the earth's atmosphere is the stratosphere. The stratosphere can be conditionally divided into 2 regions. The first of them, lying up to heights of 25 km, is characterized by almost constant temperatures, which are equal to the temperatures of the upper layers of the troposphere over a specific area. The second region, or inversion region, is characterized by an increase in air temperature to altitudes of about 40 km. This is due to the absorption of solar ultraviolet radiation by oxygen and ozone. In the upper part of the stratosphere, due to this heating, the temperature is often positive or even comparable to the surface air temperature.

Above the inversion region is a layer of constant temperatures, which is called the stratopause and is the boundary between the stratosphere and the mesosphere. Its thickness reaches 15 km.

Unlike the troposphere, turbulent disturbances are rare in the stratosphere, but strong horizontal winds or jet streams blowing in narrow zones along the borders of temperate latitudes facing the poles are noted. The position of these zones is not constant: they can shift, expand, or even disappear altogether. Often, jet streams penetrate into the upper layers of the troposphere, or vice versa, air masses from the troposphere penetrate into the lower layers of the stratosphere. Such mixing of air masses in areas of atmospheric fronts is especially characteristic.

Little in the stratosphere and water vapor. The air here is very dry, and therefore there are few clouds. Only at altitudes of 20-25 km, being in high latitudes, one can notice very thin mother-of-pearl clouds, consisting of supercooled water droplets. During the day, these clouds are not visible, but with the onset of darkness, they seem to glow due to their illumination by the Sun that has already set below the horizon.

At the same heights (20-25 km.) in the lower stratosphere there is the so-called ozone layer - the area with the highest ozone content, which is formed under the influence of ultraviolet solar radiation (you can learn more about this process on the page). The ozone layer or ozonosphere is essential to sustain life for all organisms living on land by absorbing deadly ultraviolet rays up to 290 nm. It is for this reason that living organisms do not live above the ozone layer, it is the upper limit of the spread of life on Earth.

Under the influence of ozone, magnetic fields also change, atoms break up molecules, ionization occurs, new formation of gases and other chemical compounds.

The layer of the atmosphere above the stratosphere is called the mesosphere. It is characterized by a decrease in air temperature with height with an average vertical gradient of 0.25-0.3°/100 m, which leads to strong turbulence. At the upper boundaries of the mesosphere in the area called the mesopause, temperatures up to -138 ° C were noted, which is the absolute minimum for the entire atmosphere of the Earth as a whole.

Here, within the mesopause, the lower boundary of the region of active absorption of X-ray and short-wavelength ultraviolet radiation of the Sun passes. This energy process is called radiant heat transfer. As a result, the gas is heated and ionized, which causes the glow of the atmosphere.

At altitudes of 75-90 km near the upper boundaries of the mesosphere, special clouds were noted, occupying vast areas in the polar regions of the planet. These clouds are called silver because of their glow at dusk, which is due to the reflection of sunlight from the ice crystals of which these clouds are composed.

Air pressure within the mesopause is 200 times less than at the earth's surface. This suggests that almost all the air in the atmosphere is concentrated in its 3 lower layers: the troposphere, stratosphere and mesosphere. The overlying layers of the thermosphere and exosphere account for only 0.05% of the mass of the entire atmosphere.

The thermosphere lies at altitudes from 90 to 800 km above the Earth's surface.

The thermosphere is characterized by a continuous increase in air temperature up to altitudes of 200-300 km, where it can reach 2500°C. The increase in temperature occurs due to the absorption by gas molecules of the X-ray and short-wave part of the ultraviolet radiation of the Sun. Above 300 km above sea level, the temperature rise stops.

At the same time as the temperature rises, the pressure decreases, and, consequently, the density of the surrounding air. So if at the lower boundaries of the thermosphere the density is 1.8 × 10 -8 g / cm 3, then at the upper ones it is already 1.8 × 10 -15 g / cm 3, which approximately corresponds to 10 million - 1 billion particles in 1 cm 3 .

All characteristics of the thermosphere, such as the composition of air, its temperature, density, are subject to strong fluctuations: depending on the geographical location, season of the year and time of day. Even the location of the upper boundary of the thermosphere is changing.

The uppermost layer of the atmosphere is called the exosphere or scattering layer. Its lower limit is constantly changing within very wide limits; the height of 690-800 km was taken as the average value. It is set where the probability of intermolecular or interatomic collisions can be neglected, i.e. the average distance that a chaotically moving molecule will cover before colliding with another similar molecule (the so-called free path) will be so large that, in fact, the molecules will not collide with a probability close to zero. The layer where the described phenomenon takes place is called the thermopause.

The upper boundary of the exosphere lies at altitudes of 2-3 thousand km. It is strongly blurred and gradually passes into the near space vacuum. Sometimes, for this reason, the exosphere is considered a part of outer space, and its upper boundary is taken to be a height of 190 thousand km, at which the effect of solar radiation pressure on the speed of hydrogen atoms exceeds the gravitational attraction of the Earth. This is the so-called. the earth's corona, which is made up of hydrogen atoms. The density of the earth's corona is very low: only 1000 particles per cubic centimeter, but even this number is more than 10 times higher than the concentration of particles in interplanetary space.

Due to the extremely rarefied air of the exosphere, particles move around the Earth in elliptical orbits without colliding with each other. Some of them, moving along open or hyperbolic trajectories with cosmic velocities (hydrogen and helium atoms), leave the atmosphere and go into outer space, which is why the exosphere is called the scattering sphere.

The atmosphere is the outer shell of celestial bodies. On different planets, it differs in composition, chemical and physical properties. What are the main properties of the Earth's atmosphere? What does it consist of? How and when did it originate? We will learn about this further.

Formation of the atmosphere

The atmosphere is a mixture of gases that envelop the planet from the outside and are held by its gravitational forces. At the time of formation, our planet did not yet have a gaseous envelope. It was formed a little later and managed to change several times. It is not completely known what the main properties of the atmosphere were then.

Scientists suggest that the very first atmosphere was picked up from the solar nebula and consisted of helium and hydrogen. The high temperatures of the planet and the impact of the solar wind quickly destroyed this shell.

The next atmosphere was formed by volcanoes that released gases from it. It was thin and consisted of greenhouse gases (methane, carbon dioxide, ammonia), water vapor and acids.

Two billion years ago, the state of the atmosphere began to transform into the present. External processes (weathering, solar activity) on the planet and the first bacteria and algae took part in this, due to the release of oxygen by them.

Composition and properties of the atmosphere

The gas envelope of our planet does not have a clear edge. Its outer contour is blurred and gradually passes into outer space, merging with it into a homogeneous mass. The inner edge of the shell is in contact with the Earth's crust and the Earth's hydrosphere.

What are the main properties of the atmosphere is largely determined by its composition. Most of it is represented by gases. The main share falls on nitrogen (75.5%) and oxygen (23.1%). In addition to them, atmospheric air consists of argon, carbon dioxide, hydrogen, methane, helium, xenon, etc.

The concentration of substances practically does not change. Variable values ​​are characteristic of water and are determined by the amount of vegetation. Water is contained in the form of water vapor. Its amount varies depending on geographical latitudes and is up to 2.5%. The atmosphere also contains combustion products, sea salt, dust impurities, ice in the form of small crystals.

Physical properties of the atmosphere

The main properties of the atmosphere are pressure, humidity, temperature and density. In each of the layers of the atmosphere, their values ​​are different. The air of the Earth's shell is a set of molecules of various substances. Gravitational forces keep them within the planet, pulling them closer to its surface.

There are more molecules at the bottom, so the density and pressure are greater there. With height, they decrease, and in outer space they become almost invisible. In the lower layers of the atmosphere, the pressure decreases by 1 mm Hg. Art. every 10 meters.

Unlike the planet's surface, the atmosphere is not heated by the Sun. Therefore, the closer to the Earth, the higher the temperature. For every hundred meters, it decreases by about 0.6 degrees. In the upper part of the troposphere, it reaches -56 degrees.

Air parameters are strongly influenced by the content of water in it, i.e. humidity. The total air mass of the planet is (5.1-5.3) 10 18 kg, where the proportion of water vapor is 1.27 10 16 kg. Since the properties of the atmosphere in different areas are different, standard values ​​\u200b\u200bare derived, which are taken as "normal conditions" on the Earth's surface:

The structure of the gaseous shell of the Earth

The nature of the gas envelope changes with height. Depending on what are the main properties of the atmosphere, it is divided into several layers:

• troposphere;
• stratosphere;
• mesosphere;
• thermosphere;
• exosphere.

The main parameter for differentiation is temperature. Between the layers, boundary regions are distinguished, called pauses, in which a constant temperature indicator is fixed.

The troposphere is the lowest layer. Its border runs at an altitude of 8 to 18 kilometers, depending on the latitude. Above all, it is on the equator line. Approximately 80% of the atmospheric air mass is in the troposphere.

The outer layer of the atmosphere is represented by the exosphere. Its lower boundary and thickness depend on the activity of the Sun. On Earth, the exosphere begins at an altitude of 500 to 1000 kilometers and reaches up to one hundred thousand kilometers. At the bottom it is saturated with oxygen and nitrogen, at the top - with hydrogen and other light gases.

The role of the atmosphere

The atmosphere is the air we breathe. Without it, a person will not live even five minutes. It saturates all cells of plants and animals, facilitating the exchange of energy between the body and the environment.

The atmosphere is the filter of the planet. Passing through it, solar radiation is scattered. This reduces its intensity and the harm it can cause in concentrated form. The shell plays the role of the Earth's shield, in the upper layers of which many meteorites and comets burn out before reaching the surface of the planet.

The temperature, density, humidity and pressure of the atmosphere shape the climate and weather conditions. The atmosphere is involved in the distribution of heat on the planet. Without it, the temperature would fluctuate within two hundred degrees.

The shell of the Earth is involved in the circulation of substances, is the habitat of some living beings, and contributes to the transmission of sounds. Its absence would make it impossible for life to exist on the planet.

On the surface of the Earth, meteorology deals with long-term variations - climatology.

The thickness of the atmosphere is 1500 km from the Earth's surface. The total mass of air, that is, a mixture of gases that make up the atmosphere, is 5.1-5.3 * 10 ^ 15 tons. The molecular weight of clean dry air is 29. The pressure at 0 ° C at sea level is 101,325 Pa, or 760 mm. rt. Art.; critical temperature - 140.7 °C; critical pressure 3.7 MPa. The solubility of air in water at 0 ° C is 0.036%, at 25 ° C - 0.22%.

The physical state of the atmosphere is determined. The main parameters of the atmosphere: air density, pressure, temperature and composition. As altitude increases, air density decreases. The temperature also changes with the change in altitude. Vertical is characterized by different temperature and electrical properties, different air conditions. Depending on the temperature in the atmosphere, the following main layers are distinguished: troposphere, stratosphere, mesosphere, thermosphere, exosphere (scattering sphere). The transitional regions of the atmosphere between adjacent shells are called the tropopause, stratopause, etc., respectively.

Troposphere- lower, main, most studied, with a height in the polar regions of 8-10 km, up to 10-12 km, at the equator - 16-18 km. Approximately 80-90% of the total mass of the atmosphere and almost all water vapor are concentrated in the troposphere. When rising every 100 m, the temperature in the troposphere decreases by an average of 0.65 ° C and reaches -53 ° C in the upper part. This upper layer of the troposphere is called the tropopause. In the troposphere, turbulence and convection are highly developed, the predominant part is concentrated, clouds arise, develop.

Stratosphere- layer of the atmosphere, located at an altitude of 11-50 km. A slight change in temperature in the 11-25 km layer (the lower layer of the stratosphere) and its increase in the 25-40 km layer from -56.5 to 0.8 °C (the upper layer of the stratosphere or the inversion region) are typical. Having reached a value of 273 K (0 °C) at an altitude of about 40 km, the temperature remains constant up to an altitude of 55 km. This region of constant temperature is called the stratopause and is the boundary between the stratosphere and the mesosphere.

It is in the stratosphere that the layer is located ozonosphere("ozone layer", at an altitude of 15-20 to 55-60 km), which determines the upper limit of life in. An important component of the stratosphere and mesosphere is ozone, which is formed as a result of photochemical reactions most intensively at an altitude of 30 km. The total mass of ozone at normal pressure would be a layer 1.7-4 mm thick, but even this is enough to absorb ultraviolet, which is harmful to life. The destruction of ozone occurs when it interacts with free radicals, nitric oxide, halogen-containing compounds (including "freons"). Ozone - an allotropy of oxygen, is formed as a result of the following chemical reaction, usually after rain, when the resulting compound rises to the upper layers of the troposphere; ozone has a specific smell.

Most of the short-wavelength part of ultraviolet radiation (180-200 nm) is retained in the stratosphere and the energy of short waves is transformed. Under the influence of these rays, magnetic fields change, molecules break up, ionization, new formation of gases and other chemical compounds occur. These processes can be observed in the form of northern lights, lightning, and other glows. There is almost no water vapor in the stratosphere.

Mesosphere starts at an altitude of 50 km and extends up to 80-90 km. to a height of 75-85 km it drops to -88 °С. The upper boundary of the mesosphere is the mesopause.

Thermosphere(another name is the ionosphere) - the layer of the atmosphere following the mesosphere - begins at an altitude of 80-90 km and extends up to 800 km. The air temperature in the thermosphere rapidly and steadily increases and reaches several hundred and even thousands of degrees.

Exosphere- scattering zone, the outer part of the thermosphere, located above 800 km. The gas in the exosphere is highly rarefied, and hence its particles leak into interplanetary space (dissipation).
Up to a height of 100 km, the atmosphere is a homogeneous (single-phase), well-mixed mixture of gases. In higher layers, the distribution of gases in height depends on their molecular weights, the concentration of heavier gases decreases faster with distance from the Earth's surface. Due to the decrease in gas density, the temperature drops from 0 °C in the stratosphere to -110 °C in the mesosphere. However, the kinetic energy of individual particles at altitudes of 200-250 km corresponds to a temperature of approximately 1500 °C. Above 200 km, significant fluctuations in temperature and gas density are observed in time and space.

At an altitude of about 2000-3000 km, the exosphere gradually passes into the so-called near space vacuum, which is filled with highly rarefied particles of interplanetary gas, mainly hydrogen atoms. But this gas is only part of the interplanetary matter. The other part is composed of dust-like particles of cometary and meteoric origin. In addition to these extremely rarefied particles, electromagnetic and corpuscular radiation of solar and galactic origin penetrates into this space.

The troposphere accounts for about 80% of the mass of the atmosphere, the stratosphere accounts for about 20%; the mass of the mesosphere is no more than 0.3%, the thermosphere is less than 0.05% of the total mass of the atmosphere. Based on the electrical properties in the atmosphere, the neutrosphere and ionosphere are distinguished. It is currently believed that the atmosphere extends to an altitude of 2000-3000 km.

Depending on the composition of the gas in the atmosphere, homosphere and heterosphere are distinguished. heterosphere- this is the area where gravity affects the separation of gases, because. their mixing at this height is negligible. Hence follows the variable composition of the heterosphere. Below it lies a well-mixed, homogeneous part of the atmosphere called the homosphere. The boundary between these layers is called the turbopause and lies at an altitude of about 120 km.

Atmospheric pressure is the pressure on the objects in it and the earth's surface. Normal is an indicator of 760 mm Hg. Art. (101 325 Pa). For each kilometer increase in altitude, the pressure drops by 100 mm.

Composition of the atmosphere

The air shell of the Earth, consisting mainly of gases and various impurities (dust, water drops, ice crystals, sea salts, combustion products), the amount of which is not constant. The main gases are nitrogen (78%), oxygen (21%) and argon (0.93%). The concentration of gases that make up the atmosphere is almost constant, with the exception of carbon dioxide CO2 (0.03%).

The atmosphere also contains SO2, CH4, NH3, CO, hydrocarbons, HC1, HF, Hg vapor, I2, as well as NO and many other gases in small quantities. In the troposphere there is constantly a large amount of suspended solid and liquid particles (aerosol).