求确认暗物质的阅读是不是与这个prep差不多哦

anwear · 发表于 2012-10-13 17:18:07

In the 1980's, astronomer Bohdan Paczynski proposed a way of determining whether the enormous dark halo constituting the outermost part of the Milky Way galaxy is composed of MACHO's (massive compact halo objects), which are astronomical objects too dim to be visible. Paczynski reasoned that if MACHO's make up this halo, a MACHO would occasionally drift in front of a star in the Large Magellanic Cloud, a bright galaxy near the Milky Way. The gravity of a MACHO that had so drifted, astronomers agree, would cause the star's light rays, which would otherwise diverge, to bend together so that, as observed from Earth, the star would temporarily appear to brighten, a process known as microlensing. Because many individual stars are of intrinsically variable brightness, some astronomers have contended that the brightening of intrinsically variable stars can be mistaken for microlensing. However, whereas the different colors of light emitted by an intrinsically variable star are affected differently when the star brightens, all of a star's colors are equally affected by microlensing. Thus, if a MACHO magnifies a star's red light tenfold, it will do the same to the star's blue light and yellow light. Moreover, it is highly unlikely that a star in the Large Magellanic Cloud will undergo microlensing more than once, because the chance that a second MACHO would pass in front of exactly the same star is minuscule.

wangz52 · 发表于 2012-10-16 04:50:07

考古顶顶顶撒~~~

marccc · 发表于 2012-10-16 06:34:49

顶！！

clover033 · 发表于 2012-10-19 11:39:41

感觉是。。。关键词什么的都差不多。prep2007第17篇。

ensonbobo · 发表于 2012-10-19 11:59:27

2011年9月10月的机经都有暗物质考古的同学可以注意。。。不知道2011-9，10的去哪找？

897560818 · 发表于 2012-10-19 12:07:34

顶顶顶！！！

[考古] 求确认暗物质的阅读是不是与这个prep差不多哦

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