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九.宇宙的可测性 MACHO
第一个中文版狗主确认了,连题目都一样~~~~~~
第一段说,讲的是科学家认为宇宙中可以观测到的(visible)的那些星体啊,gas啊什么的,只占到整个宇宙mass的10%。另外90%都是一些invisible的物质。天文学家们最近开始观察某东西MACHO(massive compact halo objects),然后介绍它一堆特性。我感觉我没仔细看这段,应该没啥题,因为没啥印象。
第二段说,传统的探测g物质的方法不能用了,得用新方法microlensing,如果天文学家正在看某星星,而这时这个东西正好位于观察者和星星之间时,这个星星就会异常发亮,这就证明了这种东西确实是存在的。
第三段说,天文学家发现说,MACHO物质在galaxy之内的数量比想象中多,但是没有更多的更深入的研究,天文学家就不会冒昧的猜测它的数量之类的。
结构:从质量上判断暗物质的存在,用新方法测定其存在。
Q1天文学家之前没有预料到啥?
答:选那个galaxy之下数量比想象中多。
Q2天文学家提到XX-effecience是为了说明什么
定位这个高亮单词的前面一点,态度很明确的,
effecience那个,问高亮的effecience表明了什么?
我720选:说明了到底有多少黑物质还有待研究,目前没有定论。
Q3天文爱好者为什么对dark物质感兴趣(即测定暗物质的目的)?
因为dark物质account for宇宙的大部分质量因为他们觉得黑洞可能组成了宇宙间大部分的物质的重量, (750)
Q4为什么要改进观测方法?
因为他们不知道现在overestimated多少
Q5第三段谈乱观测方法强转折处有题。
Q7考以下哪种情况不是科学家预先假设的,
这题在A和B中我不确定,因为时间比较紧来不及仔细看,原文应该能找到. A选项是黑洞的不规则的SIZE和***** B选项是microlensing这个现象大多发生在galaxy的中心,我猜了B但是感觉不对, (750)
Q8好象说以下哪个不是事实,
我选的是科学家认为microlensing大多发生在宇宙边缘(还是中心?忘记了),定位在原文的最后一句话(750)
Stava说,本文章需要注意的地方在对dark的观测。
Q9主题,我选的是说describe 了一个新的发现什么的。反正没有态度词的选项
以下这段是本人自己翻译的: = = 将就着看拉。
1980年代,天文学家BP提出了一个方法来决定 代替着MW星系最外层部分的那个巨大光晕是否是由MACHO(一种巨大的紧凑坚实物体)组成的,这种东西是一种由于太过暗淡而常不可见的天文物体。P认为如果MACHO组成了这个光晕,那么一个MACHO将会不时地漂流在一个星星LMC之前,这是一个靠近MW的明亮星体。天文学家认为MACHO的重力使得星球的light rays(本应该是偏离的)聚合在一起,然后我们就可以从地球上观察到这个星星短暂地变亮了,这样的一个过程称作microlensing. 因为许多星球个体都是本质上就是不同亮度的,一些天文学家就认为本质不同的星球亮度会被mistaken for microlensing. 然而,当星星亮的时候,本质不同的星球所发出的不同颜色的光线是给不同地影响着的,所有星星的颜色都给平等地被microlensing影响着。因此,如果一个machO放大了一个星球的红线十倍的话,它对于这个星球的蓝线跟黄线的影响也是同样的。还有,MC里面的一个星星进行microlensing多过一次这种情况是很小可能性的,这是因为第二个macho穿过在同一个星球的面前的机会是非常微小的。
In the 1980's, astronomer Bohdan Paczynski proposed a way of determining whether the enormous dark halo constituting the outermost最外层的 part of the Milky Way galaxy is composed of MACHO's(massive compact halo objects), which are astronomical天文学的 objects too dim暗淡,模糊 to be visible. Paczynski reasoned that if MACHO's make up this halo, a MACHO would occasionally drift漂流 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(偏离), 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.
Question #55. 639-01 (23881-!-item-!-188;#058&000639-01)
It can be inferred from the passage that which of the following would constitute the strongest evidence of the microlensing of a star in the Large Magellanic Cloud?
(A) The brightness of such a star is observed to vary at irregular intervals.
(B) The brightening of such a star is observed to be of shorter duration than the brightening of neighboring stars.
(C) The red light of such a star is observed to be brighter than its yellow light and its blue light.
(D) The red light, yellow light, and blue light of such a star are observed to be magnified temporarily by the same factor.
(E) The red light of such a star is observed to have increased tenfold.
Question #56. 639-04 (23927-!-item-!-188;#058&000639-04)
According to the passage, Paczynski's theory presumes that if MACHO's constituted the Milky Way's dark halo, occasionally a MACHO would
(A) drift so as to lie in a direct line between two stars in the outer Milky Way
(B) affect the light rays of a star in the Large Magellanic Cloud with the result that the star would seem for a time to brighten
(C) become obscured as a result of the microlensing of a star in the Large Magellanic Cloud
(D) temporarily increase the apparent brightness of a star in the Large Magellanic Cloud by increasing the gravity of the star
(E) magnify each color in the spectrum of a star in the Large Magellanic Cloud by a different amount
Question #57. 639-06 (23973-!-item-!-188;#058&000639-06)
The passage is primarily concerned with
(A) outlining reasons why a particular theory is no longer credited by some astronomers
(B) presenting data collected by are searcher in response to some astronomers' criticism of a particular line of reasoning
(C) explaining why a researcher proposed a particular theory and illustrating how influential that theory has been
(D) showing how a researcher's theory has been used to settle a dispute between the researcher and some astronomers
(E) describing a line of reasoning put forth by a researcher and addressing a contention concerning that line of reasoning
V2暗物质5%(高度吻合 高频 高分) = =
第一段讲:宇宙中大家知道的物质只占了5%,剩下的都是暗物质.
(第一段没什么出题点)
第二段:提问,暗物质是由什么组成的?P和N不是,接下来是"Nor can more than (不只)a few of Neutrino(中微子)怎么怎么的,意思是Neutrino也不是暗物质. 接下来高亮"一个关于newtrino的实验,说它很轻啦,速度很快啦,因此很hot "总之也不是dark matter.
第三段: 记得个fit的词(我理解是根据以上neutrino特征的反面推出的dark matter的特征), 能fit dark matter的物质具有的特点是cold, sluggish(低速)等等. 貌似在现在的cosmatic中不存在,但是在standard的假说中有一种neutranilo的物质符合
第四段: 主要讲neutronilo的,这里提到它不被electromagnetic(电磁0怎么着(在比较俩个N不同的选项里出现),同时它又是最轻的,它又很stable, 因为如果不够轻的话就会不stable从而被分成俩个更轻的(很绕的逻辑),
第二段和第四段非常长,而且有很多细节题.
Q1高亮的实验的作用
记得的选项是:1,回答段首的问题.2,支持前面那句话"nor more than".3,为了第三段什么的.我选了第二个.
2.Neutrino 和 neutranilo的描述哪个正确(以下简称n1,n2)?
1).n2在宇宙初期不被electromagnetic影响(我犹豫了下,文中是提到有,但是没有前面的宇宙初期的限定,我没选)
2).n2比n1重.(我选的这个)
3).n1不stable(文中没提)
4).n2在cosmic中实际上还没被发现?(我排除了)
3.问最后一段什么作用?
4.问第二段提到p是什么作用?
5.那个理论(standard)是用来解决什么问题的? |
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