Earth's Atmosphere

Atmosphere Basics

The atmosphere is the layer of gases surrounding Earth.
It supports life by:
- Protecting from solar radiation.
- Creating weather and climate.
- Providing gases for breathing.
Atmosphere Composition:
- 78% Nitrogen
- 21% Oxygen
- 0.04% Carbon Dioxide
- Less than 1% other gases
- Water vapor varies (up to 4% near equator, trace amounts near poles).

Troposphere
- Temperature: Decreases with height.
- Weather occurs here.
- Where we live.
- Extends 0-14 km above Earth.
Stratosphere
- Temperature: Increases with height.
- Contains the Ozone Layer.
- Planes and hot air balloons.
Ozone Layer
- Protects from Sun's harmful radiation.
- Traps heat, increasing temperature.
Mesosphere
- Temperature: Decreases (coldest region).
- Most meteors burn up here.
Thermosphere
- Temperature: Increases (very hot).
- Temps up to 1,000°C.
- Contains the Ionosphere.
Ionosphere
- Lower part of Thermosphere.
- Aurora Borealis (Northern Lights).
Exosphere
- Outer space.
- Air is very thin.
- Satellites orbit here.

Earth’s magnetic field.
About 1000km above earth’s surface
Traps harmful particles from the sun.
Particles concentrate into belts or layers called the Van Allen radiation belts.
Causes the aurora borealis in the upper atmosphere