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【v1】一篇讲galaxy的测量什么的，看得我云里雾里的 【v2】galaxy测量，说根据galaxy的发光偏红可以推测出宇宙是向外扩张的，并且某些科学家还发现了扩张的速度和路程的关系什么的，（有题目考到第二段的作用，楼主选的是，给出证据解释上面提到的一种理论）但是最后提到不知道宇宙的终结(the other end of time)是什么，有可能星球的万有引力会抵消向外扩张的力量，甚至倒转。（有考到题目，总之知道原理就能选对
galaxies的locomotion
V1 by jeanblanc
第一段是讲在1920年，发现了一个理论，好像是galaxies是不断变大的，举了个例子，就像是蛋糕里面的面粉发酵一样。然后又说道这个发现就证明了著名的Copernicus theory关于galaxies是static是错误的
第二段是讲，两位 仁兄S和M通过实验发现了red shift，然后spectral line，怎么怎么的，没怎么看懂
第三段是讲在1930年后，又发现了Huber Law，什么velocity equal to什么的，证明galaxies locomotion是uniform的
问题好像是：
1. 作者提到Copernicus theory的目的是什么：
2. 作者提到spectral line是为了证明什么
以下是关于红移（red shift) 的解释，知道的同学可以跳过（来自wiki及百科）
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In 1929 Edwin Hubble, working at the Carnegie Observatories in Pasadena, California, measured the redshifts of a number of distant galaxies. He also measured their relative distances by measuring the apparent brightness of a class of variable stars called Cepheids in each galaxy. When he plotted redshift against relative distance, he found that the redshift of distant galaxies increased as a linear function of their distance. The only explanation for this observation is that the universe was expanding.
In physics (especially astrophysics), redshift happens when light seen coming from an object that is moving away is proportionally increased in wavelength, or shifted to the red end of the spectrum. More generally, where an observer detects electromagnetic radiation outside the visible spectrum, "redder" amounts to a technical shorthand for "increase in electromagnetic wavelength" — which also implies lower frequency and photon energy in accord with, respectively, the wave and quantum theories of light.
红移在物理学和天文学领域，指物体的电磁辐射由于某种原因波长增加的现象，在可见光波段，表现为光谱的谱线朝红端移动了一段距离，即波长变长、频率降低。红移的现象目前多用于天体的移动及规律的预测上。
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下面是找的相似材料
希望狗主们确认相似度
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Meanwhile, other physicists and mathematicians working on Einstein's theory of gravity discovered the equations had some solutions that described an expanding universe. In these solutions, the light coming from distant objects would be redshifted as it traveled through the expanding universe. The redshift would increase with increasing distance to the object.
Once scientists understood that the universe was expanding, they immediately realized that it would have been smaller in the past. At some point in the past, the entire universe would have been a single point. This point, later called the big bang, was the beginning of the universe as we understand it today.
The expanding universe is finite in both time and space. The reason that the universe did not collapse, as Newton's and Einstein's equations said it might, is that it had been expanding from the moment of its creation. The universe is in a constant state of change. The expanding universe, a new idea based on modern physics, laid to rest the paradoxes that troubled astronomers from ancient times until the early 20th Century.
至于狗主所说的
："但是最后提到不知道宇宙的终结(the other end of time)是什么，有可能星球的万有引力会抵消向外扩张的力量，甚至倒转”
就自己理解吧，万有引力会抵消向外扩张的宇宙，甚至有可能最后什么都逃逸不出去就坍塌收缩回来，回到奇点，又开始big bang了？
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发表于 2013-9-12 15:17:17
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