地球：GM/(aR)^2=4π^2*aR/T 对此式进行数学变形：GM/(aR)^3=4π^2/TM/R^3=4π^2*a^3/TGM/(4πR^3/3)=3π*a^3/TGd1=M/(4πR^3/3)=3π*a^3/TG同理:d2=3π*b^3/tGd1/d2=ta^3/Tb^3
