The Structure of the Atmosphere

The Layers

• Troposphere

• Stratosphere

• Mesosphere

• Thermosphere

• * Ionosphere

• * Exosphere

Troposphere

• All weather occurs here

• All life forms live in this layer

• 75% of all gases are here

• 0-20 km in height

Stratosphere

• Most jets fly here

• Contains the ozone layer

• 20-50 km in height

Mesosphere

• Temperatures decrease with height

• Protects us from meteorites

• 50-80 km in height

Thermosphere

• Temperatures increase rapidly with height

• Air is not dense

• Greatly affected by sun’s radiation

– Absorbs gamma rays from the sun

• 80-400 km in height

Ionosphere

• Located in the lower thermosphere (80-400km)

• Contains the auroras

– Light shows in the atmosphere

• Ions: charged particles of atoms or molecules

• Ions in this part reflect radio waves back to earth

Exosphere

• Extends out into space: upper thermosphere (400km-space)

• Light gases escape from this layer into space

• 300 km to space

• Satellites travel in the exosphere