The Earth Atmosphere of layers keep meteorites from crashing into the Earth.
The troposphere is the lowest portion of Earth atmospheres.The average depth of the troposphere is approximately 17 km (11mi) in the middle latitudes .This layer is typically a few hundred metres to 2 km (1.2 mi) deep depending on the landform and time of day.It contains approximately 80% of the atmosphere's mass and 99% of its water vapour and aerosols.The troposphere is the height that an plane can fly.
The stratosphere is the second major layer of the Earth atmosphere. It is stratified in temperature, with warmer layers higher up and cooler layers farther down. At moderate latitudes the stratosphere is situated between about 10-13 km and 50 km. Stratosphere has a temperature of about 270 k, just slightly below the freezing point of water. The stratosphere is the height of how high an hot air balloon can fly.
The mesosphere is greek meso "middle" and the layer of the Earth atmosphere that is directly above the stratopause and directly below from the mesopause. In the mesosphere temperature decreases with increasing height. The upper boundary of the mesosphere is the mesopause, which can be the coldest naturally place on Earth with temperatures below 130 k. The height of the mesosphere is the highest of a spaceship can go.
The fourth layer of the atmosphere is the Thermosphere. Thermosphere is a greek word for meaning heat. Thermospheric temperatures increases with altitude due to absorption of highly energetic solar radiation. Temperatures are highly dependent on solar activity , and can rise to 2,000 C. The thermosphere is typically about 200 C hotter in the daytime than at night, and roughly 500 C hotter than when the Sun is active than at other times.
The exosphere is a thin, atmosphere-like volume surrounding a planetary body where molecules are gravitational bound to that body. The exosphere is the most upper layer, where the atmosphere thin out and merge with interplanetary space. The "air" is very very thin there. Several moons, such as Earth's moon and the Galilean satellites, exospheres without a denser atmosphere underneath.