It is no news that the major source of heat energy in the solar system is the Sun. Its energy comes from nuclear reactions that take place at its core. The energy of a particular photon created in these reactions is absorbed and reradiated many times before reaching the surface, a process that takes on average about a million years. The photon also undergoes a great degradation in energy in the course of repeated interactions with matter and with other photons throughout the Sun, emerging, most likely, as a photon of yellow-green light. A great number of photons of this light, along with fewer γ ray, x ray, ultraviolet, and other photons, interact with the atmospheres or surfaces of the planets. Almost all of the visual light of the planets is reflected sunlight. The fraction of the sunlight that is not reflected back into space is absorbed by each planet, warming its atmosphere and/or surface, which then radiates infrared radiation. The temperatures of the planets are much lower than those of the Sun because of the enormous energy output of the Sun’s nuclear furnace. It may surprise you to learn, however, that the planets have their own internal sources of heat, although these sources are much weaker in some planets than in others. In general, the planets emit more radiation than can be accounted for by current levels of solar radiation alone.
KeywordsNickel Furnace Dioxide Microwave Mercury
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References and Bibliography
- Abell, G. O., Morrison, D., and Wolff, S. C. (1987) Exploration of the Universe. Saunders, Philadelphia.Google Scholar