Biosphere and atmosphere

All the ecosystems of the Earth consists of a functional unit called the Biosphere (spheres of life). The unity of animate and inanimate nature is not limited to ecosystems, but also extends to the entire planet Earth. Biosphere consists of other parts of the Earth's sphere inhabited by living beings:

* Atmosphere, a layer of air that makes the peripheral lining of our planet;
* Hydrosphere, the water layer of the Earth and
* Lithosphere, the outer, surface, hard cover of the Earth.

                             In this picture we see the top of atmosphere

The atmosphere is a gaseous layer around the Earth or another celestial body.
Earth's atmosphere is a layer of gases surrounding the planet Earth and retained by the Earth's gravity. It contains about four fifths nitrogen and one-fifth oxygen, with the amounts of other gases in traces. The atmosphere protects life on Earth by absorbing ultraviolet solar radiation and reducing temperature extremes between day and night.

The atmosphere does not end abruptly. It slowly becomes thinner and gradually disappear in the universe. There is no definitive boundary between the atmosphere and outer space. Three-quarters of the mass of the atmosphere lies within 11 km of the planet's surface. In the United States to persons who travel above an altitude of 80 km called the astronaut. Height of 120 km marks the boundary where atmospheric effects become apparent during the spacecraft entering the atmosphere. It is also often a limit of the atmosphere and the universe takes the Kármán line at a distance of 100 km from the surface.

 Layers of the atmosphere:

-Exosphere
-Thermosphere
-Mesosphere
-Stratosphere
-Troposphere