The atmosphere of the Earth is the gas shell of our planet. By the way, almost all celestial bodies have similar shells, starting from the planets of the solar system and ending with large asteroids. The composition of the atmosphere depends on many factors - the size of the celestial body, its speed, mass and many other parameters. But only the shell of our planet contains the components that allow us to live.
Earth's Atmosphere: A Brief History of Origin
It is believed that at the beginning of its existence, our planet did not have a gas shell at all. But a young, newly formed celestial body is constantly evolving. The primary atmosphere of the Earth was formed as a result of constant volcanic eruptions. That is how, over many thousands of years, a shell of water vapor, nitrogen, carbon, and other elements (except oxygen) was formed around the Earth.
Since the amount of moisture in the atmosphere is limited, its excess turned into precipitation - this is how the seas, oceans, and other bodies of water formed. The first organisms that populated the planet appeared and developed in the aquatic environment. Most of them belonged to plant organisms that produce oxygen through photosynthesis. Thus, the Earth’s atmosphere began to be filled with this vital gas. And as a result of the accumulation of oxygen, an ozone layer was also formed, which protected the planet from the harmful effects of ultraviolet radiation. It is these factors that created all the conditions for our existence.
Earth's atmosphere
As you know, the gas shell of our planet consists of several layers - this is the troposphere, stratosphere, mesosphere, thermosphere. It is impossible to draw clear boundaries between these layers - it all depends on the time of year and the latitude of the planet.
The troposphere is the lower part of the gas shell, the height of which is on average from 10 to 15 kilometers. It is here that concentrated most of the atmospheric air. By the way, this is where all the moisture is located and clouds form. Due to the oxygen content, the troposphere supports the vital activity of all organisms. In addition, it is crucial in shaping the weather and climatic features of the area - not only clouds, but also winds form here. Temperature drops with altitude.
Stratosphere - starts from the troposphere and ends at an altitude of 50 to 55 kilometers. Here the temperature rises with height. This part of the atmosphere practically does not contain water vapor, but it has an ozone layer. Sometimes here you can notice the formation of "pearly" clouds, which can be seen only at night - it is believed that they are represented by highly condensed water droplets.
Mesosphere - stretches up to 80 kilometers up. In this layer, you can notice a sharp drop in temperature as you move up. Turbulence is also highly developed here. By the way, the so-called "silver clouds" are formed in the mesosphere, which consist of small crystals of ice - you can see them only at night. Interestingly, there is practically no air at the upper boundary of the mesosphere - it is 200 times smaller than near the earth's surface.
The thermosphere is the upper layer of the earth’s gas shell, in which it is customary to distinguish between the ionosphere and exosphere. It is interesting that with height, the temperature here rises very sharply - at an altitude of 800 kilometers from the earth's surface it is more than 1000 degrees Celsius. The ionosphere is characterized by highly liquefied air and a huge content of active ions. As for the exosphere, this part of the atmosphere smoothly passes into interplanetary space. It is worth noting that the thermosphere does not contain air.
You may notice that the Earth’s atmosphere is a very important part of our planet, which remains a decisive factor in the appearance of life. It provides vital activity, supports the existence of the hydrosphere (water shell of the planet) and protects against ultraviolet radiation.