Transcript: The distinction between intrinsic radiation and reflective radiation is very important. The Sun and all the stars, we see in their intrinsic thermal radiation, which because of their high surface temperature of thousands of degrees Kelvin comes out in the visible part of the spectrum. However the moon, the planets, and all the rocky objects of the solar system are seen in reflected radiation from the Sun, not their own intrinsic radiation. The albedo of an object is defined as the fraction of the incoming solar light that is reflected back to the Earth. An albedo of one means perfect reflectivity like a mirror. An albedo of zero means perfect absorption and no light reflected like charcoal or dark carbon. Intermediate reflections go between zero and one for the albedo. For example, a red car or a red book is reflecting the red portion of sunlight and absorbing the blue portion, while a blue car or a blue book is reflecting the blue portion of sunlight while absorbing the red portion.