According to the new rules for a planet adopted at an International Astronomical Union meeting in Prague, Pluto doesn't make the grade for a planet: a celestial body that is in orbit around the sun, has sufficient mass for its self-gravity to overcome rig
According to the new rules for a planet adopted at an International Astronomical Union meeting in Prague, Pluto doesn't make the grade for a planet: a celestial body that is in orbit around the sun, has sufficient mass for its self-gravity to overcome rig
根据在布拉格举行的国际天文联合会会议通过的行星新定义，冥王星达不到行星的级别，即：在绕太阳的轨道上运转的天体，体积足够大使其自身的重力可以克服其刚体力呈近似圆球状，且能够清除其轨道附近的其他天体。