Sentence:  The use of this concept does not specify the origin of the radiation , and only if the <WSD>planet</WSD> really radiates as a black body , will the apparent black-body temperature correspond to the physical temperature of the emitting material . 
Meaning of the word marked with <WSD> tags:  (astronomy) any of the nine large celestial bodies in the solar system that revolve around the sun and shine by reflected light; Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, and Pluto in order of their proximity to the sun; viewed from the constellation Hercules, all the planets rotate around the sun in a counterclockwise direction