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- galaxy (n.) a system of millions or billions of stars, together with gas and dust, held together by gravitational attraction (ex. the Milky Way).
- planet (n.) a celestial body moving in an elliptical orbit around a star (ex. the Earth).
- deferent (n.) (in the Ptolemaic system) the circle around the earth in which a celestial body or the center of the epicycle of its orbit was thought to move.
may 18 2014 ∞
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may 18 2014 +