|Figure A: The Atmospheric Window|
|Image from Penn State University|
Shortwave radiation (visible light) contains a lot of energy; longwave radiation (infrared light) contains less energy than shortwave radiation (shortwave radiation has a shorter wavelength than longwave radation). Solar energy enters our atmosphere as shortwave radiation in the form of ultraviolet (UV) rays (the ones that give us sunburn) and visible light. The sun emits shortwave radiation because it is extremely hot and has a lot of energy to give off. Once in the Earthâ€™s atmosphere, clouds and the surface absorb the solar energy. The ground heats up and re-emits energy as longwave radiation in the form of infrared rays. Earth emits longwave radiation because Earth is cooler than the sun and has less energy available to give off.
Figure A shows the Atmospheric Window of the wavelengths that enter our atmosphere. Our atmosphere is transparent to radio waves, visible light, and some infrared and UV radiation.