本帖最后由 taoyukun-daidai 于 2010-6-16 21:34 编辑
听写第二篇--地质学
I often hear my friends say that the days passed much more quickly than they used to. But geologically speaking, just the opposite is true. In fact a complete day which now lasts 24 hours actually used to be much shorter only about 18. How do we know that? Because of a number of finally strata rocks like these, rocks from belong ancient shorelines almost billion years ago. The tiny lines of this these samples show us layers of light and dark formed by dust belong blown over the shoreline from the line side landsite. Alternating was the mud and sand with mudden sands deposit by the waves, so the space between one dark strata drive then and the next emphases of the time between on monthly high tide and the next. And the verying in finesses of layers show us the circle of seasons as well together the data indicate that there were fewer months for a year way back then. That means that the moon was moving more slowly than as it that revolved around the earth. So what caused the moon does speed up so much over the last billion years? It must be the tides. Think about it, as the gravity of moon pulls on the oceans to form the tides all that water is also pulling on the moon. And with each rotation that it makes the moon move a tiny bit faster, at the same time like the brakes on the wheel of bicycle, the drag caused by the moon's gravity makes the earth turn just a tiny bit slower. So after a billion years or so, one rotation meaning one day takes a lot longer than it once did.
继续跟读20遍。加油！！！ 这次跟读感觉好多了，至少原速是没有问题了。 | 
发表于 2010-6-13 22:45:47
发表于 2010-6-14 18:23:07
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