Sometimes the atmosphere surrounding our planet with a thick layer is called the fifth ocean. No wonder the second name of the aircraft is an aircraft. The atmosphere is a mixture of various gases, among which nitrogen and oxygen prevail. It is thanks to the latter on the planet that life is possible in the form to which we are all accustomed. In addition to them, there is another 1% of other components. These are inert (not entering into chemical interactions) gases, sulfur oxide, carbon dioxide. Also, the fifth ocean contains mechanical impurities: dust, ash, etc. All layers of the atmosphere in total extend almost 480 km from the surface (data are different, we will dwell on this point in more detail below). Such an impressive thickness forms a kind of impenetrable shield that protects the planet from destructive cosmic radiation and large objects.
The following atmospheric layers are distinguished: the troposphere, followed by the stratosphere, then the mesosphere and, finally, the thermosphere. The given order begins at the surface of the planet. Dense layers of the atmosphere are represented by the first two. They filter a significant part of the destructive cosmic radiation.
The lowest layer of the atmosphere - the troposphere, extends only 12 km above sea level (18 km in the tropics). Here, up to 90% of water vapor is concentrated, so clouds form in it. Most of the air is also concentrated here. All subsequent layers of the atmosphere are colder, since proximity to the surface allows reflected sunlight to heat the air.
The stratosphere extends to almost 50 km from the surface. Most weather balloons “float” in this layer. Also, some types of aircraft can fly here. One of the amazing features is the temperature regime: in the interval from 25 to 40 km, air temperature begins to rise. From -60 degrees Celsius it rises to almost 1. Then there is a slight decrease to zero, which persists to an altitude of 55 km. The upper bound is the infamous ozone layer.
Further to almost 90 km, the mesosphere extends. The air temperature here drops sharply. For every 100 meters of climb, a decrease of 0.3 degrees is observed. Sometimes it is called the coldest part of the atmosphere. Air density is low, but it is quite enough to create resistance to falling meteors.
Layers of the atmosphere in the usual sense end at an altitude of about 118 km. Famous auroras form here. Above begins the area of the thermosphere. Due to x-rays and ultraviolet rays , the few air molecules contained in this area are ionized. These processes create the so-called ionosphere (it is often included in the thermosphere, therefore it is not considered separately).
Everything above 700 km is called the exosphere. The concentration of air molecules is extremely low, so they move freely, without experiencing resistance due to collisions. This allows some of them to accumulate energy corresponding to 160 degrees Celsius, while the ambient temperature is low. Gas molecules are distributed over the exosphere in accordance with their mass, so the heaviest of them can be found only in the lower part of the layer. The planet’s gravity, decreasing with height, is no longer able to hold molecules, therefore cosmic high-energy particles and radiation give gas molecules enough momentum to leave the atmosphere. This area is one of the longest: it is believed that the atmosphere completely passes into cosmic vacuum at altitudes greater than 2000 km (sometimes even the number 10000 appears). Artificial satellites of the planet rotate in orbits in the thermosphere.
All these numbers are approximate, since the boundaries of the atmospheric layers depend on a number of factors, for example, on the activity of the Sun.