地球有自转和公转，研究表明说地球自转旋转的时间变短。这是怎么一回事呢?今天，就让我们跟随着北京新航道托福频道小编一起去了解一下吧，为托福阅读积累的知识和素材，下面请看。
地球的旋转时间变短
We have been talking about some of the effects that the human beings had on the earth. One you may not be aware of is that we actually begin to change the length of the day. In the other way to say, one day is the amount of time the earth needs to spin completely around an axis, the imaginary line around the center of the earth, from the north to the south. And of course there are a lot of physical causes that can affect the speed of the earth’s rotation, but there was only one that is direct result of the human activity. Since 1950, human beings have built about ten thousand artificial reservoirs all over the world. These reservoirs have redistributed tremendous amount of the earth water. 来源：北京新航道托福培训When they are used to be in the area near the equator, the imaginary line surround the middle of the earth, it’s now the reservoirs in the areas of different latitudes. The latitude matters because, well, thinking the earth and axis, the equator contains the areas on the earth that are the farthest away from axis. So water has been redistributed from the equator regions, then wherever the water is, to it’s close to the earth axis. It’s like when ice skaters perform spins when those skaters put their arms enclose to their bodies, they spin faster. So the earth is spinning faster because the reservoirs have redistributed the water close to its axis. And because the earth was spinning faster, since 1950 the length of day has decreased by about 8 millionth of second. I know that doesn’t sound like much but significant in that this is the first time that human beings ever had measurable affect on the earth’s motion.
上面就是关于地球的旋转时间变短的托福阅读知识，希望大家认真看看，读一读，同时也可以自己的知识积累，加油!
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