一天内日地距离的比较

Comparison of distance between sun and earth in a day

根据天文年历有关太阳参数，通过理论计算，发现日地距离的日变化具有一定规律：一天中正午太阳与观测者之间的距离，比日出日落两者间的距离，近的日期多于远的日期，两者的比率随着纬度的增加逐渐减小．

According to the related parameters of astronomical calendar, the auther proved that there is some regulation in changes of the distance between the sun and the earth by theoritical caculation. In a year, thera are more days during which the distaces between the sun and the observer at te precisely noon is nearer than that of at the time of sun rusing, the ratio of the two dates decreases with the increase of latitude.