Atmosphere of the Earth: the history of appearance and structure

The Earth's atmosphere is the gas envelope of ourplanet. By the way, almost all celestial bodies have such 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.

Atmosphere of the Earth: a brief history of the origin

It is believed that at the beginning of its existence, ourthe planet did not have a gas shell at all. But the young, newly formed heavenly body was constantly evolving. The primary atmosphere of the Earth was formed as a result of constant volcanic eruptions. This is how many thousands of years around the Earth formed a shell of water vapor, nitrogen, carbon and other elements (except oxygen).

Since the amount of moisture in the atmosphereis limited, its excess turned into precipitation - so formed the seas, oceans and other water bodies. In the aquatic environment, the first organisms that inhabited the planet appeared and developed. Most of them belonged to plant organisms that produce oxygen by photosynthesis. Thus, the Earth's atmosphere began to be filled with this vital gas. And as a result of the accumulation of oxygen, the ozone layer 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.

The structure of the Earth's atmosphere

As is known, the gas envelope of our planetconsists of several layers - 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 site of the planet.

The troposphere is the lower part of the gas shell,the height of which is an average of 10 to 15 kilometers. It is here that concentrated most of the atmospheric air. By the way, this is where all the moisture is and clouds form. Due to the oxygen content, the troposphere supports the life of all organisms. In addition, it is crucial in the formation of weather and climatic conditions of the terrain - there are formed not only clouds, but also winds. The temperature drops with altitude.

Stratosphere - starts from the troposphere andends at an altitude of 50 to 55 kilometers. Here the temperature increases with altitude. This part of the atmosphere practically does not contain water vapor, but it has an ozone layer. Sometimes here you can see the formation of "pearly" clouds, which can be seen only at night - it is believed that they are represented by strongly condensed water droplets.

The mesosphere stretches up to 80 kilometers to the sky. In this layer, you can notice a sharp drop in temperature as you move up. Turbulence is also highly developed here. By the way, in the mesosphere so-called "noctilucent clouds" are formed, which consist of small ice crystals - you can see them only at night. It is interesting that there is practically no air near 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 terrestrial gasshell, in which it is customary to distinguish between the ionosphere and the exosphere. It is interesting that with altitude 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 dilute air and a huge content of active ions. As for the exosphere, this part of the atmosphere gradually turns into interplanetary space. It is worth noting that the thermosphere does not contain air.

It can be noted that the Earth's atmosphere is veryan important part of our planet, which remains the decisive factor in the emergence of life. It provides life, supports the existence of the hydrosphere (the water shell of the planet) and protects against ultraviolet radiation.