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(1) A planet1 is a celestial body that (a) is in orbit around the Sun, (b) has suffi cient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape, and (c) has cleared the neighbourhood around its orbit
(2) A dwarf planet is a celestial body that (a) is in orbit around the Sun, (b) has suffi cient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearl << 上一页 [11] [12] [13] [14] 下一页
时间：2009-4-21 17:32:30
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