地球绕太阳公转的速度为每秒30公里，绕太阳一周需要365天5时48分46秒，也就是一年，天文学上称之为回归年。地球绕太阳公转的轨道是一个椭圆，它的长直径和短直径相差不大，可近似为正圆。大阳就在这个椭圆的一个焦点上，而焦点是不在椭圆中心的，因此地球与太阳的距离就有时会近一点，有时会远一点。一月初，地球离大阳最近，为147100000公里，这一点叫做近日点。七月初地球离大阳最远，为152 100000公里，这一点叫做远日点。事实上，当地球在近日点的时候，北半球为冬季，南半球为夏季;在远日点的时候，北半球为夏季，南半球为冬季。这就说明，四季的变化与近日点和远日点无关
（翻译成英文 不要用在线翻译工具）谢谢了
第1个回答 2014-03-16
The earth revolves around the sun in the speed of 30 kilometers per second, around the sun takes 365 days to five forty-eight 46 seconds, there is just one year, called the tropical year on astronomy. The earth revolves around the sun's orbit is an ellipse, the long diameter and short diameter difference, can be approximated as a perfect circle. The sun was a focus of the ellipse, and the focus is not on the ellipse center, so the distance between earth and the sun is sometimes a bit closer, sometimes a little farther. At the beginning of the January, the nearest to the earth, 147100000 kilometers, it is called perihelion. Seven early Earth farthest from the sun, is 152100000 kilometers, it is called aphelion. In fact, when the earth is at perihelion, the northern hemisphere winter, the southern hemisphere summer at aphelion; when, the northern hemisphere summer, the southern hemisphere winter. This shows, the changes of the seasons and the perihelion and aphelion independent追问
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