LSAT 132 – Section 2 – Question 20

LSAT 132 - Section 2 - Question 20

December 2010

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Question
QuickView		 Type Tags Answer
Choices		 Curve Question
Difficulty		 Psg/Game/S
Difficulty		 Explanation
PT132 S2 Q20
+LR
Resolve reconcile or explain +RRE
Causal Reasoning +CausR
A
2%
155
B
5%
159
C
67%
166
D
24%
158
E
2%
153
148
157
166
 +Harder 148.345 +SubsectionMedium

Astronomer: Earlier estimates of the distances of certain stars from Earth would mean that these stars are about 1 billion years older than the universe itself, an impossible scenario. My estimates of the distances indicate that these stars are much farther away than previously thought. And the farther away the stars are, the greater their intrinsic brightness must be, given their appearance to us on Earth. So the new estimates of these stars’ distances from Earth help resolve the earlier conflict between the ages of these stars and the age of the universe.

"Surprising" Phenomenon

Why does knowing these stars are farther from Earth resolve the discrepancy between their age and the age of the universe?

Objective

Any hypothesis explaining why this conflict is resolved must imply that the stars are younger than previously estimated or that the universe is older than previously estimated. Correcting the distances of these stars from Earth was enough to resolve the conflict, so the correct answer must imply that more distant stars imply an older universe or that knowing stars are more distant allows scientists to know they are younger.

A
The stars are the oldest objects yet discovered in the universe.

This does not state that the universe is older than previously estimated, nor does it provide a reason for concluding so. It remains unexplained why updating the stars’ distances resolves the apparent conflict between the age of the stars and the age of the universe.

B
The younger the universe is, the more bright stars it is likely to have.

This makes the resolution more surprising. Since the stars are more distant, they have a greater inherent brightness to achieve the same apparent brightness here on Earth. Therefore, this suggests the universe should be younger than previously estimated, not older.

C
The brighter a star is, the younger it is.

This explains why correcting the stars’ distances resolves the conflict. If the stars are more distant than believed, they must have a greater intrinsic brightness to achieve the same apparent brightness. This means they are younger than the earlier estimates suggest.

D
How bright celestial objects appear to be depends on how far away from the observer they are.

This is not enough information to explain why the conflict is resolved. It is a generalization of the astronomer’s claim that farther stars must have a greater intrinsic brightness to achieve the same apparent brightness on Earth.

E
New telescopes allow astronomers to see a greater number of distant stars.

This is irrelevant information. Improved telescopes may explain how the stars’ distances were corrected, but not how that correction resolves the conflict regarding their age.

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LSAT PrepTest 132 Explanations

Section 1 - Reading Comprehension

Section 2 - Logical Reasoning

Section 3 - Reading Comprehension

Section 4 - Logical Reasoning

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