IDEAS ABOUT THE UNIVERSE
   As long ago 340 B.C. Aristotle,in his book On the Heavens ,was able to put forward two good arguments for believing that the Earth was a round
ball rather than a flat plate .First,he realized that eclipses of the moon were caused by the Earth coming between the sun and the moon. The Earth's shadow on the moon was always round, which would be true only if the Earth was spherical. If the Earth had been a flat disk, the shadow would have been elongated and elliptical, unless the eclipse always occurred at a time when the sun was directly above the center of the disk.

   The Greeks even had a third argument that the Earth must be round, for why else does one first see the sails of a ship coming over the horizon and only later see the hull? Aristotle thought that the Earth was stationary and that the sun, the moon, the planets, and the stars moved in circular orbits about the Earth. He believed this because he felt, for mystical reasons,that the Earth was the center of the universe and that circular motion was the most perfect.

   Ptolemy's model provided a reasonably accurate system for predicting the positions of heavenly bodies in the sky. But in order to predict thesepositions correctly, Ptolemy had to make an assumption that the moon followed a path that sometimes brought it twice as close to the Earth as at other times. And that meant that the moon had sometimes to appear twice asbig as it usually does. Ptolemy was aware of this flaw but nevertheless his model was generally, althought not universally, accepted. It was adopted by the Christian church as the picture of the universe that was in accordance with Scripture. It had the great advantage that it left lots of room outside the sphere of fixed stars for heaven and hell.

   A much simpler model, however, was proposed in 1514 by a Polish priest, Nicholas Copernicus. At first, for fear of being accused of heresy, Copernicus published his model anonymously. His idea was that the sun was stationary at the center and that the Earth and the planets moved in circular orbits around the sun. Sadly for Copernicus, nearly a century passed before this idea was to be taken seriously. Then two astronomers --the German, Johannes Kepler, and the Italian, Galileo Galilei-- started publiclyto support the Copernican theory, despite the fact that the orbits it predicted did not quite match the ones observed. The death of the Aristotelian-Ptolemaic theory came in 1609. In tnat year Galileo started observing the night sky with a telescope, which had just been invented.

   When he looked at the planet Jupiter, Galileo found that it was accompanied by several small satellites, or moons, which orbited around it. This implied that everything did not have to orbit directly around the Earthas Aristotle and Ptolemy had thought. It was, of course, still possible to believe that the Earth was stationary at the center of the universe, but that the moons of Jupiter moved on extremely complicated paths around the Earth, giving the appearance that they orbited Jupiter. However, Copernicus's theory was much simpler.

我来翻译一下

     关于宇宙的观点
    
    
     早在公元前340亚里士多德,他的书放在诸天,才能够提出两个很好的论点认为地球是圆的
     球而不是平板上,他意识到日蚀月球是由地球来临太阳和月球之间。月球上的地球阴影总是圆的,这可能是真的只有地球是球形。如果地球扁平圆盘,影子就会被拉长,椭圆形,除非月蚀时总是出现在太阳圆盘中心。

第二,希腊人从他们的旅行的北极星出现在天空时,在南部相比,更北的地区。从不同的位置在北极星在埃及和希腊,亚里士多德甚至引用了一位估计距离围绕地球是四十万的体育场馆。现在还不知道到底什么是一个体育馆,但它可能是大约200码。这将使亚里士多德的估计,大约有两次当前公认的图。

希腊人甚至有第三种观点认为地球是圆的,为什麽要先看了另外一艘船的航行将出现在视野中,然后再看看船体吗?亚里斯多德认为地球是静止不动的和太阳、月亮、星星的行星,而在圆形轨道移动地球。他认为,这是因为他觉得,神秘的原因,认为地球是宇宙的中心,圆周运动是最完美的。

这个想法是由托勒密家族在公元1世纪。成一个完整的宇宙学模型。地球站在中心,包围了8球,而月亮、太阳、星星、五个星球认识当时水星、金星、火星、木星、土星。这个行星上的小圆自己移动连接到他们各自的球体,为了解释他们的相当复杂的观察天空中的路径。所谓的最外层领域进行固定恒星,它始终保持在同样的位置相对于每一个其他而一起旋转划过天空。最后的范围之外什么从来都做的很清楚,但它并不是人类的可见宇宙的一部分。

   At the same time, Kepler had modified Copernicus's theory, suggesting that the planets moved not in circles, but in ellipses. The predictions now finally matched the observations. As far as Kepler was concerned, elliptical orbits were merely an ad hoc hypothesis--and a rather repugnant one at that because ellipses were clearly less perfect than circles. Havingdiscovered, almost by accident, that elliptical orbits fitted the observations well, he could not reconcile with his idea that the planets were made to orbit the sun by magnetic forces.

托勒密家族的模型提供了一个合理的位置准确预测系统的天体在天空。但是为了正确预测这种系统,托勒密不得不做出一个假设,月亮是路径,有时带来了两次接近地球一样。这意味着,月亮也出现了两倍大通常都是不一样的。托勒密家族意识到了这个缺陷不过他的模型,但并不普遍,普遍接受。这是由基督教教堂,图片的宇宙,依照《圣经》。它有很大的优势,它留下的大量的房间外球面固定恒星的天堂和地狱。

一个更简单的模型,提出了,但1514由波兰牧师,尼古拉斯·哥白尼。起初,因为害怕被指责的异端,哥白尼出版他的模型隐蔽。他的想法是太阳被固定在中心和地球和其他行星搬进循环绕着太阳转。遗憾的是,对哥白尼,近一个世纪之后,这种想法是我们必须认真对待。那两个天文学家——德国、约翰尼斯·开普勒、意大利、伽利略——开始公然支持哥白尼原理,尽管事实是预测轨迹的不完全匹配。亚里士多德学派-托勒密的理论来在1609年逝去。在那年伽利略观察夜晚的天空和望远镜,刚刚被发明了。