以下是引用strout在2007-5-24 13:52:00的发言:Q12: Which of the following, if true, would most clearly undermine the possible explanation for the whirling gas in M87 that is mentioned in the last sentence of the first paragraph? - The stars in a star cluster at the center of M87 could exert a strong gravitational force without tearing the cluster apart.
- A cluster of stars at the center would preclude the existence of certain other astronomical phenomena that have been observed at the center of M87.
- The stars within many existing galaxies, such as NGC 4258, are more closely spaced than are the stars within the core of M87.
- Only one other galaxy has been observed to contain gas clouds whirling about its center as they do about the core of M87.
- The gravitational force of a cluster of a billion or so dim stars would be sufficient to cause a whirling ring of gas and dust to collect around the center of a galaxy.
答案是A 谢谢strout,我把这道题认真分析了一遍,确实是B。 怀疑者辩解说:解释急速旋转的气团所必须的星云团聚集现象在黑洞来说并非必须的:M87内部可能是一簇亿万个暗星体的聚集。 Q12的B选项说:中心存在一簇星团的天体不可能同时存在M87中心所观测的那样一些天体现象(言下之意:M87内部的不是所谓的暗星,从而起到削弱作用) B选项开始没有很准确的理解是由于preclude没有理解,Longman解释,Preclude:to prevent something or make something impossible。看来抽象词的理解需要加强了!! 我更新了jj中“黑洞存在的研究”,并增加了上述的解释,请大家注意改过来了。  |