SSS 2009-01-01
时间：2018-12-24 作者：英语课 分类：Scientific American(一)月
- 1 SSS 2009-01-01
This is Scientific American's 60-Second Science. I'm Steve Mirsky . Got a minute
Happy New Year! And don’t feel bad about taking today off. After all, you’ve traveled far. And I’m not talking about the trip home from the party last night. According to NASA, just by being on the planet Earth in the last year, you’ve zipped about 584 million miles around the sun to get back where you were. At an average speed of about 67,000 miles per hour. Again, not talking about the drive home last night.
Of course, the trip was not a perfect circle. As Kepler showed, the Earth’s orbit is an ellipse, with the sun at one of the two focal points. He also figured out the planet goes faster when it’s at perihelion, nearer the sun, than when it’s at aphelion 1, its farthest distance—which would explain why summer seems to zip by, except the seasons are a function of the tilt 2 of the Earth’s axis 3, not its different distances from the sun. And the Earth rotated 365 and a quarter times during its sweep around the sun. The trip took 8,766 hours. Or 31,557,600 seconds. Or 525,960 minutes just like this one.
Thanks for the minute for Scientific American's 60-Second Science. I'm Steve Mirsky .
- 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。