The world around us is formed from three very different parts: earth, water and air. Each of them is unique and interesting in its own way. Now we are talking only about the last of them. What is the atmosphere? How did it come about? Of what does it consist and on which parts it is divided? All these questions are extremely interesting.
The very name "atmosphere" is formed from two words of Greek origin, in translation into Russian they mean "pairs" and "ball". And if you look at the exact definition, you can read the following: "The atmosphere is the air shell of the planet Earth, which is carried along with it in outer space." It developed parallel to the geological and geochemical processes that took place on the planet. And today all the processes that take place in living organisms depend on it. Without the atmosphere, the planet would become a lifeless desert, like the Moon.
What does it consist of?
The question of what the atmosphere is and what elements it includes have interested people for a long time. The main components of this shell were already known in 1774. They were installed by Antoine Lavoisier. He found that the composition of the atmosphere is mainly formed from nitrogen and oxygen. Over time, its components were refined. And now it is known that there are many more gases in it, as well as water and dust.
Let us consider in more detail what the Earth's atmosphere is about near its surface. The most common gas is nitrogen. It contains a little more than 78 percent. But, despite such a large amount, in the air, nitrogen is practically not active.
The next in number and very important element is oxygen. This gas contains almost 21%, and it shows very high activity. Its specific function is to oxidize the dead organic matter, which, as a result of this reaction, decomposes.
Gases with a low content, but an important value
The third gas, which is part of the atmosphere, is argon. Its slightly less than one percent. After it go carbon dioxide with neon, helium with methane, krypton with hydrogen, xenon, ozone and even ammonia. But they are so small that the percentage of such components is equal to the hundredth, thousandth and millionth parts. Of these, only carbon dioxide plays an important role, since it is the building material that is necessary for plants for photosynthesis. Another important function is to not pass radiation and absorb part of the solar heat.
Another small but important gas - ozone exists to contain ultraviolet radiation coming from the Sun. Due to this property all life on the planet is reliably protected. On the other hand, ozone affects the temperature of the stratosphere. Because it absorbs this radiation, the air is heated.
The constancy of the quantitative composition of the atmosphere is maintained by non-stop mixing. Its layers move both horizontally and vertically. Therefore, anywhere in the world there is enough oxygen and there is no excess of carbon dioxide.
What else is present in the air?
It should be noted that steam and dust can be detected in the airspace. The latter consists of pollen and soil particles, in the city they are joined by impurities of solid emissions from exhaust gases.
But there is a lot of water in the atmosphere. Under certain conditions, it condenses, and clouds and fog appear. In fact, it is one and the same, only the first appear high above the surface of the Earth, and the latter spreads over it. The clouds take a variety of forms. This process depends on the height above the Earth.
If they formed 2 km above the land, they are called layered. It is from them that rain is falling on the ground or snow falls. Over them to a height of 8 km cumulus clouds are formed. They are always the most beautiful and picturesque. It is they who are considered and guess what they look like. If such formations appear on the next 10 km, they will be very light and airy. Their name is pinnate.
What layers does the atmosphere share?
Although they are very different from each other temperature, it is very difficult to say at what particular height of one layer starts and another ends. This division is rather conditional and is approximate. However, the atmosphere still exist and perform their functions.
The lowest part of the air envelope is called the troposphere. Its thickness increases when moving from the poles to the equator from 8 to 18 km. This is the warmest part of the atmosphere, because the air in it is heated from the earth's surface. Most of the water vapor is concentrated in the troposphere, so clouds form in it, precipitation falls, thunder and wind blows.
The next layer has a thickness of about 40 km and is called the stratosphere. If the observer moves to this part of the air, he will find that the sky has become purple. This is due to the low density of matter, which practically does not scatter the sun's rays. It is in this layer that jet planes fly. For them, all the open spaces are open there, since there are practically no clouds. Inside the stratosphere there is a layer consisting of a large amount of ozone.
After it go the stratopause and mesosphere. The latter has a thickness of about 30 km. It is characterized by a sharp decrease in the density of air and its temperature. The sky for the observer is seen in black. Here you can even watch the day in the stars.
Layers in which there is practically no air
Continues the structure of the atmosphere layer called the thermosphere - the longest of all the others, its thickness reaches 400 km. This layer is characterized by a huge temperature, which can reach 1700 ° C.
The last two spheres are often combined into one and called it the ionosphere. This is due to the fact that they react with the release of ions. It is these layers that allow one to observe a phenomenon of nature, like the northern lights.
The next 50 km from the Earth are allotted to the exosphere. This is the outer shell of the atmosphere. In it, air particles are scattered into space. In this layer, weather satellites usually move.
The Earth's atmosphere ends with a magnetosphere. It was she who sheltered most of the artificial satellites of the planet.
After all that has been said, there should not be any questions about what the atmosphere is. If there is any doubt about its necessity, it is easy to dispel them.
The significance of the atmosphere
The main function of the atmosphere is to protect the planet's surface from overheating during the day and excessive cooling at night. The next important significance of this shell, which no one will dispute, is to supply oxygen to all living beings. Without this, they would suffocate.
Most meteorites burn in the upper layers, and not reaching the surface of the Earth. And people can admire the flying lights, taking them for the falling stars. Without the atmosphere, the whole Earth would be dotted with craters. And the protection against solar radiation has already been mentioned above.
How does a person affect the atmosphere?
Very negative. This is due to the growing activity of people. The major share of all negative moments is accounted for by industry and transport. By the way, it is cars that give off almost 60% of all pollutants that penetrate the atmosphere. The remaining forty divide between themselves energy and industry, as well as industries for the destruction of waste.
The list of harmful substances that daily replenish the composition of air is very long. Because of transport in the atmosphere are: nitrogen and sulfur, carbon, sine and soot, as well as a strong carcinogen, causing skin cancer - benzopyrene.
The industry accounts for such chemical elements: sulphurous gas, hydrocarbon and hydrogen sulfide, ammonia and phenol, chlorine and fluorine. If the process continues, then soon answers to the questions: "What is the atmosphere? What does it consist of? "Will be completely different.