atmosphere is the gas layer that surrounds and accompanies the Earth in all its movements, due to the force of gravity, in addition to having the function of balancing the temperature of theplanet.
The atmosphere is made up of several important gases for life, such as the oxygen, nitrogen and carbon dioxide, that form a transparent, colorless and odorless mixture called atmospheric air. In addition to gases, there is also water vapor, dust particles, micro-organisms, etc.
The heaviest gases in the atmosphere are concentrated closer to the earth's surface and the lighter ones are further away. As altitude increases, the atmosphere becomes thinner and thinner (at higher altitudes we feel short of air). At 80 km of altitude oxygen is almost non-existent, as it is a heavy gas, it does not stay at high altitudes.
THE atmosphere it is part of the geographic stratum along with the "lithosphere" (set of rocks and soils), the "hydrosphere" (set of all waters on the planet) and the "biosphere" (elements found in the atmosphere, lithosphere and hydrosphere). These components are related to each other, that is, they are interdependent: any change in one of them implies a change in the set.
See also:meaning of the Lithosphere.
Atmosphere layers
The atmosphere is formed by five layers from the Earth's surface to the outermost one:
- Troposphere - Reaches up to about 10 to 12 km in altitude and concentrates 75% of gases and 80% of atmospheric moisture (water vapor, ice crystals, etc.). that form the clouds). It is the layer in which atmospheric disturbances occur. As it rises, it can reach -60°C at the top, which is called the tropopause.
- Stratosphere – Extends from the troposphere to about 50 km. Water vapor is almost non-existent and no clouds form. It is an important region due to the presence of ozone, which filters most of the ultraviolet rays emitted by the sun. The temperature increases with altitude, reaching 2°C at the top.
- mesosphere – It starts the so-called upper atmosphere and goes from the tropopause to 80 km in altitude. Unlike what happens in the stratosphere, here the temperature decreases with altitude (the air is thinner), reaching -90°C at the upper limit.
- Ionosphere – Extends from the mesosphere to about 600 km. Air is very rarefied and charged with ions (electrified particles that have the property of reflecting radio and TV waves). It is in this layer that meteors (shooting stars) disintegrate. The temperature can reach up to 1000°C at the top.
- exosphere – It is the outermost layer of the atmosphere. It starts at about 600 km altitude, with imprecise upper limits. The lack of air allows very high temperatures (more than 1000°C).
Greenhouse effect
The greenhouse effect is an atmospheric phenomenon that consists of the retention of heat radiated by the earth's surface, by particles of gases and water in suspension, ensuring the maintenance of the planet's thermal balance, therefore, the survival of plant species (which process photosynthesis) and animals.
An imbalance in the atmospheric composition, caused by the high concentration of certain gases capable of absorbing heat, such as the methane, carbon dioxide and nitrous oxide cause a greater storage of heat that is reflected back to the earth resulting in the effect. stove.
Acid rain
Acid rain is another atmospheric phenomenon caused, on a local or regional scale, by pollution emitted by industries, transport and other forms of combustion. The main factors responsible for this phenomenon are sulfur dioxide, emitted from the burning of fossil fuels, oxygen already present in the atmosphere and nitrogen dioxide emitted by vehicles self-propelled.
Find out more about the Atmosphere layers and Troposphere.
