Nearly all the energy in Earth's atmosphere comes from the sun.
- travels to Earth as electromagnetic waves
-waves are classified by wavelength
Most of the energy from the sun reaches Earth in the form of...
- visible light
- infrared radiation (IR)  is felt as heat
- ultraviolet radiation (UV) causes sunburn and skin cancer
Light scattering (the reflection of light in all directions) is why we see the sky as blue.
Gas molecules scatter short wavelengths of visible light.
The denser the atmosphere, the more the light gets scattered
At dawn and dusk, the sky appears red, orange, and yellow.
Light must travel through more atmosphere, scattering more light.
Only the longer wavelengths of visible light make it to our eyes at this time.
Energy from the Sun travels through space and the atmosphere
Earth's surface absorbs solar energy heating the land and water.
Some of this energy radiates into the atmosphere as IR.
Earth's surface also reflects some of the energy into the atmosphere.
Clouds, dust, and gases...
can reflect and scatter light
absorb solar energy (very small amount)
Heat gets trapped in the atmosphere.  This is the greenhouse effect
- natural process
- greenhouse gases include, but are not limited to...
-water vapor
-carbon dioxide