Question premise: what most clearly undermines the explanation for the whirling gas being a cluster of dim stars? --> So I was looking for answers that would show the whirling gas couldn't be stars or could only be something else other than stars.I also chose C incorrectly, since I inferred that if the stars were more closely spaced than others that meant that the whirling gas must have been from a black hole. I didn't understand some of the other explanations from other users on why this was incorrect and instead B was correct, so I looked up the word "preclude" and now B makes sense as correct answer.
Preclude means "to prevent from happening; make impossible", hence the existence of a cluster of stars at the center would
PREVENT other astronomical phenomena observed at the center of M87, therefore it cannot be a cluster of stars there.
However I did not know what "preclude" meant while I was testing so I tried to figure out a different logic that would have helped arrive at B as correct answer. I read C again, I see that I misinterpreted it and therefore could have eliminated C and chosen B just by process of elimination.
"The stars within many existing galaxies, such as NGC 4258, are
more closely spaced than are the stars within the core of M87". --> Later in passage says "if 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." C only tells us that NGC 4258 was
MORE closely spaced than the stars within the core of M87, so then that means the
potential stars in M87 were actually farther apart than NGC 4258 and therefore
could have been stars that were not torn apart. So it ultimately doesn't undermine the sentence saying that a concentration of mass could be a cluster of stars, and can be eliminated.
A and E both support the explanation so they are eliminated, and D doesn't provide any information on this other galaxy that also has gas clouds so that is eliminated. Therefore B is the answer.
proabhinav wrote:
3. 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?
(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.
Dear All
Anyone , please can you advice reasons for C over B. I was confused between these two and chose C, reasons that in the passage " 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. ". I inferred from this sentence that the finding was of not a star cluster but something else, if not black hole.
I thought this undermines the explanation.
Please can anyone advice, happy to be advised if you believe my understanding of the passage is not correct, I did find the last sentence confusing.