The exosphere is the outermost component of earth atmosphere. In this region
the gravitational forces on air particles are very weak. So some particles
can already escape into space.
Thermo- or Ionosphere
This layer reaches a height of about 200km. The layer is named ionosphere because
of the ions. In this layer a high concentration of ions can be found. A ion
is a atom with more or less electrons than protons. The layer reflects radio
waves coming from earth. This feature allows long range radio communication
The mesosphere reaches heights of about 80 km. In the mesosphere temperature
dropes to about -80°C. In the above thermosphere the temperature increases
again and reaches finally temperatures of about 2000°C.
The stratosphere reaches heights of about 48km. An interesting fact is the ozon
layer in about 25 km height. By this layer the earth surface is shielded against
high energetic ultra violet radiation.
The lowest layer is finally the troposphere. This layer reaches heights
of about 15 km. In this region more then 90% of the mass of atmosphere
is concentrated. Temperature decreases of about 6.5°C per kilometer. Also
the troposphere is very important for mankind because the whole weather phenomena
are produced their.