The atmosphere comes from Greek, the word "atmos" which means steam and "sphaira" which means sphere. Thus, the atmosphere is the layer of gas that envelopes the Earth's sphere. Because this layer envelopes the Earth, the atmosphere is much wider than the ocean covering 3/4 of the Earth's surface.
If "sky" is defined as an atmosphere, then the letter says that the atmosphere has 7 layers. However, in meteorology only known 5 layers of the atmosphere.
The five layers, as shown in the figure below, are:
1. Troposphere (0-10 km). The lowest layer, where the weather phenomenon (clouds, rain, and thunderstorms) occurs.
2. Stratosphere (10-50 km). The layer above the troposphere where the weather phenomenon has ceased to occur. However, large thunderstorms can reach the lower layers of the stratosphere. In this layer, there is an ozone layer.
3. Mesosphere (50-85 km). Layers where vertical air movement is not too obstructed.
4. Thermosphere (above 85 km). A hot coating with a temperature between 400 ° -2000 ° C.
Among these layers, there is a boundary that separates each layer of the tropopause, stratopause, and mesopause.
In the above description, there are 4 layers of the atmosphere. If the ozone layer is calculated as a separate layer, then there are 5 layers. However, it turns out that in astronomy science is known another layer above the thermosphere layer, namely the ionosphere and the exosphere. If the overall layer is summed, the number is indeed 7 layers.
The atmospheric gas is composed of a fixed amount of gas and an amount of gas. The fixed gases consist of nitrogen, oxygen, hydrogen, helium, and other low-grade gases. While the amount of gas that changes consist of water vapor, carbon dioxide, and ozone. The composition of the air is located in the lower atmosphere (0-25 km). The percentage can be seen in the pie chart below.
The atmosphere is compressible, meaning the maximum density (mass density) is at the surface of the soil. Since density is a function of volume, the gases will become thinner if away from the surface, until it can not be distinguished from space gas/dust. The thickness of the atmosphere ranges from 100-110 km, but the thickness is different in each place. In the polar and subtropical regions, the thickness is only about 8 km, while in the tropics reaches 16 km.
In the troposphere layer in the atmosphere, there are various weather processes that play a role in maintaining survival on Earth. Seasonal / weather shifts play a role in wind direction. In addition to helping pollinate plants, winds moving from low to high temperatures also spread the clouds. The rain from the clouds makes the barren land come alive again.
With its ozone layer, the atmosphere also protects the Earth from ultraviolet radiation, which is very harmful to living things on Earth. In addition, the atmosphere also protects the Earth from the entry of foreign objects. Foreign objects entering the Earth will rub against the atmospheric layer from a height of 100 km down. The closer to Earth, the concentration of the air the more concentrated and the density is higher, so the greater the frictional force. As a result, when reaching the Earth's surface, the size of the object has been reduced or even burned out.
During the day, the atmosphere reflects 6% and absorbs 16% of the heat energy from the sun. Then solar thermal energy is passed to the surface, about 24% of the amount is reflected back by clouds and the Earth's surface, 3% absorbed by the cloud. The rest (51%) is absorbed by land and sea. Thus, the Earth's surface temperature during the day does not soar.
In contrast, at night the atmosphere retains some of the heat energy so the temperature does not degenerate dramatically. The atmosphere absorbs about 15% of the heat energy to be emitted back into space. The ability of the atmosphere to absorb heat caused by its CO2 gas content, similar to a greenhouse (herbarium) that keeps the temperature warm for the plants in it. Therefore, CO2 gas is also called greenhouse gas. However, the amount of this gas in the atmosphere continues to rise, causing global warming.
Conclusion:
From the above description it can be concluded that without the atmosphere with the composition and thickness like that of Earth, there will be no life. This is what makes other planets-in spite of the atmosphere has no life. The atmosphere of other planets is not thick enough to withstand attacks of foreign objects. In addition, the composition does not allow the occurrence of weather processes and heat containment.http://blogeducationforstudents.blogspot.com/2018/03/why-sky-is-blue.html