It's no secret that the air - an extremely important part of the biosphere.After all, its unique formulation provides the possibility of life on the planet.But the name of the air environment of the Earth?What is it and what is unique?What is the chemical composition and physical properties?These issues are of interest to many.
What is the aerial shell of the Earth?
known that life on Earth is possible thanks in part to the unique composition of the air.And gas shell is called the atmosphere.This part of the biosphere completely surrounds the planet and held around a celestial body by gravity.
Naturally, this shell has a certain chemical and physical properties.As for the borders, it is clearly impossible to conduct them.Closer to the surface in contact with the atmosphere and hydrosphere, lithosphere.But to determine where it ends and begins gaseous envelope open space, it is extremely difficult.To date, the border taken hold at an altitude of 100 km, where the so-called line of pocket - in the area aeronautics longer possible.
atmosphere - air shell of the Earth, whose value is difficult to overestimate.After all, we should not forget that almost all celestial bodies are under the influence of ionizing and ultraviolet radiation are harmful to living organisms.It is in the gaseous envelope of the rays are neutralized.
theories of atmospheric
In fact, many people wondered how the air shell of the Earth was formed.The answer is unlikely to be accurate, as of today there are several different theories about the origin of the atmosphere.
According to the most common hypothesis, the primary atmosphere was formed four billion years ago from the light gases - namely, hydrogen and helium, which were seized from interplanetary space.Due to the high volcanic activity in the future create a secondary shell of gas that was saturated with carbon dioxide, water vapor and ammonia.
Tertiary atmosphere was formed through many processes - the chemical reactions (eg, lightning), ultraviolet exposure, leakage of helium and hydrogen back into interplanetary space.
chemical composition of the atmosphere
Now, when it became the name of the air shell of the Earth, it is necessary to consider its chemical composition, which is considered unique.Immediately it should be noted that the various gases are saturated with only the lower layers of the atmosphere.In particular, in the air we breathe predominates nitrogen (78.08%).The oxygen level is 20.95%.These are two major gas.
Furthermore, the air environment of the earth, and includes other components - is carbon dioxide, hydrogen, argon, helium, xenon, methane, sulfur oxides and nitrogen, ozone, ammonia.
structure of the air bag Earth
The atmosphere can be divided into several layers, each of which has different physical and chemical characteristics.
- troposphere - the layer closest to the earth's surface.It is concentrated 80% of the air.And it is here possible human activity.Incidentally, in this layer is concentrated almost all the atmospheric water (90%).There are formed clouds and precipitation.The troposphere extends for 18 km from the earth's surface.With the rise of the temperature up here is reduced.
- stratosphere (12-50 km) - layer, which is considered the most tranquil part of the atmosphere.This is where the ozone protective layer.
- thermosphere - part of the atmosphere, which is the upper limit of about 700-800 km.Here, the temperature begins to rise sharply with increases in some areas is about 1,200 degrees Celsius.Within the boundaries of this layer is the so-called ionosphere, where the air is ionized by solar radiation.
- exosphere - scattering area, which at an altitude of 3000 km passes into space.The air is filled with light gases such as hydrogen and helium.
basic physical characteristics of the atmosphere
Of course, the physical properties of the air extremely important.For example, knowing them, you can determine how the atmosphere affects the human or any other living organism.In addition, measurement of the physical parameters is essential for determining the optimum characteristics of aircraft, aircraft, etc... In particular, we have considered the following physical parameters:
- air temperature is measured by the following formula: t1 = t - 6,5H (heret - the temperature at the surface, and H - height).
- air density - is the weight per cubic meter of air.
- pressure that can be measured in pascals, and atmosphere.
- Humidity demonstrates the amount of water per unit of air.It should be noted that the zero humidity is only possible in the laboratory.The higher the score, the lower the density of the air, and vice versa.
way, science, giving an answer to questions about how the name of the air shell of the Earth, what are its properties and characteristics - a meteorology.Researchers are studying not only the atmosphere, but also to monitor its continuous changes that affect weather and climate.
atmosphere and its value
importance of the gaseous envelope of the Earth is very difficult to overestimate.After a few minutes without air lead to loss of consciousness, hypoxia and irreversible brain damage.Only thanks to the amazing composition of the atmosphere of living organisms they can get the necessary oxygen.
In addition, the air shell protects the planet's surface from harmful cosmic radiation.However, the atmosphere passes through a sufficient amount of ultraviolet rays, which warms the earth.Scientists say that a reduction in ultraviolet light would lower the overall temperature and freezing.In addition, under the influence of sunlight (in reasonable quantities) in human skin tissue formed vitamin D.
ozone layer and its importance
in the stratosphere at an altitude of 12-50 km from the earth's surface, the ozone layer.This part of the atmosphere was discovered in 1912 by French scientists Sh A. Buisson and Fabry.
Ozone is a colorless gas with a pungent characteristic odor.It is composed of three atoms of oxygenation.This part of the gas shell protect the earth's surface from harmful cosmic radiation.
Unfortunately, due to technological and industrial developments in the air shell of the Earth has increased the amount of harmful substances, which can gradually erode the ozone layer.The so-called ozone hole - a very dangerous problem.
Air pollution: greenhouse effect and acid rain
Unfortunately, the constant air pollution, which is mainly due to industrial development, leading to mass deterioration.These dangerous changes include the so-called greenhouse effect.The fact that the earth body waves radiate predominantly infrared spectrum - they can not always penetrate through the atmosphere.Increasing concentrations of greenhouse gases that absorb infrared radiation (water vapor, carbon dioxide) increases the overall temperature in the lower atmosphere, which, respectively, affect the climate.
Acid rain - another result of industrial pollution of the earth's shell.Sulfur and nitrogen oxides, which are emitted into the air by thermal power plants, cars, steel mills and some other enterprises, can react with water vapor of the atmosphere - under the influence of solar radiation is formed acid, which fall along with other sediments.
