开普勒第三定律(r~3)/(T~2)=k,式中周期的测量容易理解,但圆轨道半径r的值是怎么测算的呢?参阅了大量的资料,20世纪60年代前测天体距离主要用三角视差法。由于天体距离遥远,视差非常小,所以基线必须长,通常以地球的半径作为基线。先是测量地球的半径,再测月球和地球的距离,后是 Kepler’s third law (r ~ 3) / (T ~ 2) = k, where the periodic measurements easy to understand, but the radius of circular orbit r is how to measure it? See a lot of information, the 20th century 60 Before the antecedent measured the distance between celestial bodies mainly by triangular parallax method. Since the celestial bodies are far apart and the parallax is very small, the baseline must be long, usually with the radius of the earth as the baseline. First measure the radius of the earth, then measure the distance between the moon and the earth, the latter is