“阿波罗号”载人宇宙飞船把岩石和土壤样品从月球表面带回地球以后，科学家发现，地球与月球的氧同位素比例是一样的，月球的组成成分与地幔成分极为相似．这些证据表明，地球与月球可能原为一体．但有数据表明，地球和月球的密度却是不相同的． 设天体的质量为Ｍ，平均半径为 After the “Apollo” manned spacecraft brought rock and soil samples back to Earth from the lunar surface, scientists discovered that the oxygen isotope ratios of the Earth and the Moon are the same, and the composition of the Moon is very similar to that of mantle components. The evidence shows that the Earth and the Moon may be one. However, there are data showing that the density of the Earth and the Moon is not the same. Let the mass of the celestial body be M and the average radius be