(Aka. longwave radiation) Electromagnetic radiation that has a wavelength longer than that of visible light (400–700 nm), but which is shorter than that of terahertz radiation (100 µm – 1 mm) and microwaves.
1. The direct-sunlight spectrum consists of 47% infrared radiation, 46% visible light, and 6% ultra-violet light.
2. Atmospheric greenhouse gases absorb and then re-radiate this radiation back to the surface, thereby creating the greenhouse effect.