天文学知识及生活常识都告诉我们,太阳在每时每刻不间断地向周围宇宙空间辐射着能量.根据著名的爱因斯坦质能方程,可以推知,太阳自身的质量应在不断地减小;由牛顿万有引力定律知道,在太阳自身质量不断减小的同时,太阳对地球的万有引力也应该在不断减小.根据牛顿第二定律及圆周运动规律,假设运动速率不变,在向心力减小的时,做圆 Astronomy knowledge and common sense tell us that the sun radiates energy to the surrounding cosmic space uninterruptedly at any moment in time.According to the well-known Einstein's equation of mass energy, we can deduce that the quality of the sun itself should be continuously reduced. According to Newton's law of universal gravitation, while the mass of the sun is decreasing, the gravitation of the sun to the earth should also be decreasing constantly.According to the Newton's second law and the law of circular motion, assuming that the rate of motion is constant, when the centripetal force decreases , Do round