SSS 2012-01-02
时间：2018-12-24 作者：英语课 分类：Scientific American(一)月
Happy new year and don’t feel bad about taking today off, after all, you’ve travelled far. And I’m not talking about the trip home from the party. According to NASA, just by being on the planet earth last year, you’ve zipped about 584 million miles around the sun to get back what you were. And an average speed about 67000 miles per hour. Again, not talking about the drive home from the party, of course the trip was not perfect circle. As kepler show, the earth orbit is an ellipse, with the sun in one of two focal points. They also figured out the planet goes faster when its at perihelion, nearer the sun, than when its at aphelion 1 ,its further distance, which would explain why summer seems to zip by ,except the seasons are a function of the tilt 2 of the earth axis 3 not its different distance from the sun. and the earth rotated 365 and a quater times during its sweep around the sun. The trip took 8766 hours or 31,557,600 seconds or 525,960 minutes just like this one.
- The point in the orbit nearest the sun is called perihelion,while the point farthest is called aphelion.在轨道上最接近太阳的点被称为近日点，而最远离太阳的点被称为远日点。
- But it's not that simple either,because the dates of the perihelion and aphelion are also shifting.但这并不是简单的一件事情,因为近日点和远日点的日期都会变换。