Planets, as the term is used for this category, are the eight solar system bodies which meet the International Astronomical Union definition of the word as described in http://www.iau.org/fileadmin/content/pdfs/Resolution_GA26-5-6.pdf
Sites about an individual planet should be submitted to the appropriate subcategory. Sites about solar system planets in general or about more than one planet should be submitted here. Sites about planets outside our solar system should be submitted to http://dmoz.org/Science/Astronomy/Extrasolar_Planets/

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Jupiter is the 5th planet out from the sun and is the largest planet in the solar system. Sites in this category deal with this planet, its magnetic field, and its system of rings and moons.
Only sites dealing specifically with Jupiter or its system in general should be placed in this category. Sites dealing with the satellites alone should be placed in the Jupiter'' moons family of categories while sites dealing with Jupiter''s decametric and kilometric radio emissions should be placed in the Radio Observations category

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Mars is the 4th planet out from the sun. Sites in this category deal with this planet, and its moons.
Only sites dealing specifically with Mars or its system in general should be placed in this category.
Mercury is the closest planet from the Sun.
Please only submit websites with relevant content which adds something to the category.