For the Earth, it is one because we work in astronomical units. 地球也是一个,因为我们用天文单位(AU)。
A law stating that the ratio of the square of the revolutionary period ( in years ) to the cube of the orbital axis ( in astronomical units ) is the same for all planets. 说明所有行星的运行周期的平方(年)和轨轴的三次方(天文单位(AU))的比例都一样的定律。