关于黑洞存在的那篇，gwd-27-12

cournot

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?                 

1. The stars in a star cluster at the center of M87 could exert a strong gravitational force without tearing the cluster apart (L34-38)

2. 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.

3. The stars within many existing galaxies, such as NGC 4258, are more closely spaced than are the stars within the core of M87.

4. Only one other galaxy has been observed to contain gas clouds whirling about its center as they do about the core of M87.

5. 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

关于黑洞存在的那篇，这个答案A,但是A正好是support 第一段最后一句'the possible explanation for the whirling gas in M87 '，我觉得答案应该是把without tearing the cluster apart 改成with tearing the cluster apart。

原文如下： Astronomers theorize that a black

            hole forms when a massive object

            shrinks catastrophically under its own

Line gravity, leaving only a gravitational

  (5)field so strong that nothing escapes it.

Astronomers must infer the existence

of black holes, which are invisible,

from their gravitational influence on

the visible bodies surrounding them.

 (10)For example, observations indicate

that gas clouds in galaxy M87 are

whirling unusually fast about the gal-

axy’s center. Most astronomers

believe that the large concentration

 (15)of mass at the galaxy’s center is a

black hole whose gravity is causing

the gas to whirl.  A few skeptics have

argued that the concentration of mass

necessary to explain the speed of the

 (20)whirling gas is not necessarily a black

             hole: the concentration in M87 might

             be a cluster of a billion or so dim stars.

  The same hypothesis might have

been applied to the galaxy NGC 4258,

 (25)but the notion of such a cluster’s

existing in NGC 4258 was severely

undermined when astronomers mea-

sured the speed of a ring of dust and

gas rotating close to the galaxy’s

 (30)center. From its speed, they calcu-

lated that the core’s density is more

than 40 times the density estimated

            for any other galaxy. If the center of

NGC 4258 were a star cluster, the

 (35)stars would be so closely spaced

that collisions between individual

stars would have long ago torn the

cluster apart.

 

[此贴子已经被作者于2006-6-18 10:54:49编辑过]

二狼神

是呀,A有点看不懂.

cournot

没有人看到么？

Iawfy

can you please post the entire passage

梦不落

最后一段最后一句话是虚拟语气。也就是说此观点认为，如果是cluster of stars，那它们肯定很久以前就因为collision而torn apart。A说的是相反，说不会torn apart。这就削弱了阿。

vanessav

据说问的是 第一段的最后一句啊  ～～～～～～～～～～～～～～～～～～～～～～～～～～～～～～～

jacqui

我觉得应该是b.

在中央的一团星体和在中央观察到的其它一些现象相矛盾。

ly365

ding

everann

      If the center of
   

      NGC 4258 were a star cluster, the
   

 (35)stars would be so closely spaced
   

  that collisions between individual
   

  stars would have long ago torn the
   

  cluster apart.
  

如果中心是个star cluster的话,那么这些星星会因为太近而相撞从而把cluster的结构破坏

答案A说cluster中心提供的重力可以保持这个cluster的结构而不被torn apart，当然应该选A咯。

[此贴子已经被作者于2006-7-20 22:25:18编辑过]

mymengming

支持B

A是支持了,不是削弱

文章问的是削弱