[問題]GWD27-Q10~Q12

[chour]

Q10 to Q12:
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.

Q10:
The skeptics mentioned in the first paragraph would be most likely to agree with the astronomers mentioned in line 13 about which of the following statements concerning the galaxy M87?

考兩派理論的相同點

A. The speed of the gas whirling around the center of M87 is caused by a dense object that is not a black hole.
B. The concentration of mass at the center of M87 is probably a large cluster of dim stars.
C. The presence of a black hole at the center of M87 is the most likely explanation for the speed of the gas whirling about the galaxy’s core.
D. The speed of the gas whirling around the center of M87 is caused by a large concentration of mass at the core of M87.
E. The gravitational influence of a star cluster would not be strong enough to account for the speed of the gas whirling around the core of M87.
Answer: D--------------------------------------------------------------------------------
Q11:
The passage asserts which of the following about the existence of black holes?

從L6~9可以推論得知

A. Astronomers first speculated about the existence of black holes when they observed gas whirling around the center of a particular galaxy.
B. Evidence used to argue for the existence of black holes is indirect, coming from their presumed effects on other astronomical bodies.
C. Recent observations of certain astronomical bodies have offered proof.
D. A considerable body of evidence suggests the existence of black holes, even though their behavior is not completely consistent with the laws of physics.
E. Many astronomers are skeptical about certain recent evidence that has been used to argue for the existence of black holes.
Answer: B--------------------------------------------------------------------------------
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?

A. The stars in a star cluster at the center of M87 could exert a strong gravitational force without tearing the cluster apart.
B. 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.
C. The stars within many existing galaxies, such as NGC 4258, are more closely spaced than are the stars within the core of M87.
D. Only one other galaxy has been observed to contain gas clouds whirling about its center as they do about the core of M87.
E. 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.
Answer:A

求助Q12,這題考點是要weaken第二派(a few skeptics)的說法
選項A看起來比較像是support
選項B,如果第二派為真,則以往發現的其他現象則不可能出現,感覺很有weaken的效果~~

CD上似乎也是爭議這兩個選項,可以麻煩各位伸出援手嗎?

[hcgh]

我覺得答案應該是B

B. 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.
如果M87的中心是cluster of stars的話，那麼原本M87有的現象，現在都不會存在。
當然是weaken "M87中心是cluster of stars囉"

那A為什麼不對？
A. The stars in a star cluster at the center of M87 could exert a strong gravitational force without tearing the cluster apart.
既然M87中心的star不會導致collision，那當然就support M87中心有可能是star cluster囉。

但CD上有些人支持A

第一段最后一句说不一定是黑洞，有可能是因为很多星星组成。要削弱，只要证明是黑洞就行了。根据第二段的内容，很多星星的话，就会tear the cluster apart，但A中说有很大的重力，却without tearing the cluster apart，因此说明不是星星，就有可能是黑洞了。所以削弱。

不知道这么理解对不对，如果M87是star cluster的话，就会因为collision而torn apart
现在因为他们没有torn apart（不管什么原因），所以M87不是star cluster
从而weaken第一段最后一句话：M87是star cluster

支持A的理由，都是基於 "如果M87中心是star cluster, 就會collision"
但是這不是事實，因為文章是說NGC 4258的中心如果是cluster, 就會collisoin.
而
From its speed, they calcu-
lated that the core’s density is more
than 40 times the density estimated
for any other galaxy.
NGC 4258的core density比M87大了40倍
所以"NGC 4258的中心如果是cluster, 就會collisoin"並不適用於M87上
所以A是不對的

[auguding]

感覺2邊說的通
有高手可以解答嗎?

[A級垂耳兔]

有時候真的很受不了那些CD的文章...有些人整個文章沒看懂就上來鬼扯蛋...爭議題搞到後來每個答案都有人支持...有時候一看都一百多篇...馬上傻眼...
那不如用骰子決定比較快....

隨便拿個例子來看看...

第一段最后一句说不一定是黑洞，有可能是因为很多星星组成。要削弱，只要证明是黑洞就行了。根据第二段的内容，很多星星的话，就会tear the cluster apart，但A中说有很大的重力，却without tearing the cluster apart，因此说明不是星星，就有可能是黑洞了。所以削弱。

誰看得懂紅色部分在寫什麼...也沒說明為什麼會這樣....看不懂他在寫什麼當然支持B了...因為B也不知道在寫什麼....

我先說說最後一句我的解讀...
文章最後一句話是承接上一句話而來...上一句話主要是以旋轉速度間接推論有黑洞存在...最後一句同樣也支持有黑洞的結論....
請注意最後一句是用"與現在事實相反假設".....翻譯一下...
要是4258星系是一群行星組成...那這些行星必須靠非常近(但靠非常近的結果自己想一下...靠太近..行星互相有引力)....以致於相互產生碰撞...星系早就撕裂了...

看不懂作者在鬼扯什麼吧?這時要發揮一點想像力....
想像到了嗎? 就是說要是4258真的是一群"靠的非常近"的行星組成...早就因引力互相吸引碰撞爆炸...由原本星系中心高密度高引力的行星群...轉變成散開來低密度低引力的行星群...這樣子就不能用"不發光行星群"來解釋87星系的高引力成因...只能用"有黑洞"來解釋
我為何敢這樣推論...看第一段有說明懷疑論說強烈引力不一定來自黑洞..可能來自一群不發光的行星...想一下若是要有和黑洞一樣的引力...一定是有重量相當的引力...我想這個文章要有點天文常識...聚集越多星體當然重量越大..引力越大...
抱歉扯太多了~~~

這種天文學的文章就是要發揮想像力....看一下第12題....

答案A...就說在87星系的行星可以產生強大引力但不會撕裂星群.....
有可能是靠太近不會碰撞產生高密度高引力...或是不需要靠太近也可以產生高引力(這個文章沒說..不得而知)...但不管是哪一個...就推翻了原來最後一句話說:
靠太近早就碰撞爆炸造成星群撕裂....而推論不可能是一群行星產生高引力(從句子用與現在事實相反假設推斷)...是黑洞產生高引力
這個才是答案~~~

答案B...星群阻止某些其他天文現象存在於87星系中心....
請注意本題就像是考CR....看到這種答案你敢選嗎? 用了"other"..."certain"...根本不知所云...文章也沒提到...如何做推論...最後一句都不知道作者想說什麼...要如何用這個答案weaken??這個答案光是用考試技巧就排除了.....

[crystal0o]

我支持B
題目問的是"反駁第一段懷疑論者的理論:M87不是黑洞而是一群星體
...
各位不要把第一段的內容跟第二段搞混了！
第二段是說另外一個銀河系，密度40倍大於任何其他銀河系
所以推論4258不是cluster！
但是！
該題問的是：請反駁M87的懷疑論者的理論，
等於我們要找個答案反駁 M87是cluster的理論！
而第一題...他混淆把第二段的條件加近來
A.The stars in a star cluster at the center of M87 could exert a strong gravitational force without tearing the cluster apart.
~~>所以支持M87的中心不是黑洞是cluster
A錯！因為答案要的是支持

B.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.

如果M87的中心是cluster，會排除一些"已經被發現的天文現象的存在"
反駁B的中心不是cluster

支持答案是B...
還請各位提供意見!

[crystal0o]

修正:
A錯..因為答案要的是反駁而不是支持！

[keane0727]

B加１　

[willyyang]

我支持B (雖然我在考試的時候選了A ><)

這個題目是在否定第一段最後一句話--the concertration in M87 might be a cluster of a billion or so dim stars.

(A)沒有辦法否定，因為一開始就說了"the stars in a star cluster" ，怎麼看都不像否定，比較像支持。
(B)如果a cluster of stars at the center會排除一些"已經被發現的天文現象的存在"

另外我想問一下，第二段一開頭的 the same hypothesis是指 a few skeptics的看法嗎？

請NN指正並回答，感謝。

[kausnow]

支持B

理由同willyyang

[lucyyeh]

Q10:
The skeptics mentioned in the first paragraph would be most likely to agree with the astronomers mentioned in line 13 about which of the following statements concerning the galaxy M87?

A. The speed of the gas whirling around the center of M87 is caused by a dense object that is not a black hole.
B. The concentration of mass at the center of M87 is probably a large cluster of dim stars.
C. The presence of a black hole at the center of M87 is the most likely explanation for the speed of the gas whirling about the galaxy’s core.
D. The speed of the gas whirling around the center of M87 is caused by a large concentration of mass at the core of M87.
E. The gravitational influence of a star cluster would not be strong enough to account for the speed of the gas whirling around the core of M87.

請問第10題的B是錯在哪呀?

[dibert8]

Q10
Most astronomers
believe that the large concentration
(15)of mass at the galaxy’s center is a
black hole

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.

對於 concentration of mass, astronomers 認為是 balck hole, skeptics 認為不是:是 a cluster of a billion or so dim stars
(B) 是 skeptics 的主張, astronomers 並不認為如此.

[dibert8]

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?
A. The stars in a star cluster at the center of M87 could exert a strong gravitational force without tearing the cluster apart.
B. 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.

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.
M87 不是 balck hole, 是 a cluster of a billion or so dim stars.

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.
a star cluster 的說法不正確,因為若 gravity 是導致 collisions 早該使 cluster 分散開來.

(A) exert a strong gravitational force without tearing the cluster apart 正好與 line37~39 相反; 弱化的方式是"同因不同果" (strong gravitational force 使得 M87 和 NGC4258 處於相同的前提)
(B) 文章沒有提 other astronomical phenomena ;沒有定義,不能據以否定.

[auguding]

答案A我有一個疑惑
第一段說明科學家認為M87應該是由clster of stars組成而非black hole
下一段說~這樣的假設也可用於NGC 4258--->但是該理論在此被推翻--->因為the speed of a ring of dust and gas rotating close to the galaxy’s center. If the center of NGC 4258 were a star cluster, the stars would be so closely spaced that collisions between individual stars would have long ago torn the cluster apart.
所以可知~再第一段下的假設論證--->M87應該由cluster of stars組成在第2段被推翻了--->就是由於speed因素會tear them apart
答案A就是否定了第2段中的這個理論--->說明了應該是由black hole才對吧!
但是我有點看不懂~A. The stars in a star cluster at the center of M87 could exert a strong gravitational force without tearing the cluster apart.這裡面不就已經說了stars in a star cluster了嗎? 不就沒法推翻第一段最後一句說的:他是由cluster stars組成????變成好像是要推翻第2段的論成而不是推翻第一段ㄟ~變支持~

我的盲點在哪~~~~

反之~B選很像OK~但是那個certain other真的很難下決定!

[auguding]

求救啊~
高手~~~~
我還是被這題的迷思困住了...

[chris8888]

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(關鍵字)
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.

Q10:
The skeptics mentioned in the first paragraph would be most likely to agree with the astronomers mentioned in line 13 about which of the following statements concerning the galaxy M87?

考兩派理論的相同點

A. The speed of the gas whirling around the center of M87 is caused by a dense object that is not a black hole.
B. The concentration of mass at the center of M87 is probably a large cluster of dim stars.
C. The presence of a black hole at the center of M87 is the most likely explanation for the speed of the gas whirling about the galaxy’s core.
D. The speed of the gas whirling around the center of M87 is caused by a large concentration of mass at the core of M87.
E. The gravitational influence of a star cluster would not be strong enough to account for the speed of the gas whirling around the core of M87.

Q11:
The passage asserts which of the following about the existence of black holes?

從L6~9可以推論得知

A. Astronomers first speculated about the existence of black holes when they observed gas whirling around the center of a particular galaxy.
B. Evidence used to argue for the existence of black holes is indirect, coming from their presumed effects on other astronomical bodies.
C. Recent observations of certain astronomical bodies have offered proof.
D. A considerable body of evidence suggests the existence of black holes, even though their behavior is not completely consistent with the laws of physics.
E. Many astronomers are skeptical about certain recent evidence that has been used to argue for the existence of black holes.