The word Atmosphere comes from the Greek words atmos (fluid, vapor) and spharia (sphere, globe), it is the gaseous layer that surrounds a celestial body; for example, on the planet Mercury there is a very thin atmosphere, thus indicating the low presence of gases.
On our planet Earth, the atmosphere is made up of a mixture of gases that we know as air, and is composed mainly of nitrogen (78%) and oxygen (21%), other component gases are: hydrogen, helium, neon, argon, krypton, xenon and radon.
At higher altitudes the composition changes, lowering some elements, including nitrogen and helium, disappearing others such as oxygen and argon, and greatly increasing hydrogen, which at 100 km of altitude reaches a proportion of 99.3% of the air volume.
We must also name the so-called accidental components, which are found in variable quantities in different places and terrestrial environments: carbon dioxide or carbon dioxide, carbon monoxide and ammonia.
The atmosphere is essential for the development of life on Earth, since it contains the oxygen that living beings breathe, acts as a reflector of solar rays, through the ozone layer, and also regulates the appropriate temperature on Earth..
The terrestrial atmosphere is considered divided into the following layers or concentric zones, from the surface upwards we have: the troposphere , the layer of air in contact with the Earth, where meteorological changes that originate the weather and atmospheric disturbances take place.
The stratosphere has a thickness of about 30 km, it is very important because the ozone layer is found there. The mesosphere is about 40 km thick, in this area there are clouds of ice and dust, and the meteorites that fall to Earth become incandescent (shooting stars).
The ionosphere , also called the thermosphere, because its temperature reaches values above 1000 ºC, is the highest and widest layer of the atmosphere, its outermost part is called the exosphere , which is formed by loose molecules due to direct action of the sun.
It should be noted that man is the one who can most harm the conservation and the future of the atmosphere that is already in danger; Atomic radiation, carbon dioxide and carbon monoxide emanating from refineries, steel mills and automobiles, sulfur dioxide that causes smog, nitrogen oxides, phosphates, pesticides, oil, mercury and lead, are some of the agents disturbers and pollutants in the atmosphere.
