The overwhelming heat you feel on a boiling hot summer day does not all come directly from the sun. Rather, warm temperatures we feel on the earth are also a result of Earth's conversion of the sun's visible light to infrared radiation. This heat is an essential part of the Earth's radiation balance.

Other planets, such as Mars, also convert the sun's visible light to infrared radiation; however, Mars' climate is nothing like Earth's. Why is Mars so freezing cold (and variable) while Earth is warm and habitable? There clearly is another important factor at work in Earth's radiation balance.