Mercury is a liquid metal, and mercury, the planet, is the fastest moving naked eye heavenly body. Mars, iron, why is Mars red?

水银是液态金属，水银，行星，是肉眼能看到的运动最快的天体,火星，铁，为什么火星是红色的？

麻省理工公开课 - 固态化学导论课程节选

By putting the two together, out comes the elliptical motion of the planets.

将这两个式子联立,就得到了行星作椭圆运动的方程

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and they tell you the answer, which will be some elliptical motion.

他们会告诉你答案,行星会做椭圆运动

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At this instant, the planet may be moving at that speed.

在这个时刻,行星可能在以这个速度运动

耶鲁公开课 - 基础物理课程节选

Then again, you will find the evolution of the planetary motion, because the rate of change of the rate of the change of the position is connected to the position.

同样地,这就是行星运动的演化过程,因为行星位移的变化率的变化率,与它的位移有关

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