SSS 2012-01-02（在线收听）

 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 ,its further distance, which would explain why summer seems to zip by ,except the seasons are a function of the tilt of the earth axis 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.