PT132.S2.Q20

PrepTest 132 - Section 2 - Question 20

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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. ██ █████████ ██ ███ █████████ ████████ ████ █████ █████ ███ ████ ███████ ████ ████ ██████████ ████████ ███ ███ ███████ ████ ███ █████ ████ ███ ███████ █████ █████████ ██████████ ████ ███ █████ █████ ██████████ ██ ██ ██ ██████ ██ ███ ███ █████████ ██ █████ ██████ █████████ ████ █████ ████ ███████ ███ ███████ ████████ ███████ ███ ████ ██ █████ █████ ███ ███ ███ ██ ███ █████████

Argument Summary

This is an unusual stimulus for a Resolve, Reconcile, Explain-type question, because it has a full argument structure with premises and a conclusion. The astronomer tells us about a problem: earlier estimates of how far some stars were from Earth suggested that the stars are older than the universe itself, which can't be true. The astronomer's estimates, however, suggest that the stars are much farther away than was previously thought, and therefore much brighter than they were originally thought to be. The astronomer concludes that her estimates help resolve the earlier conflict between the ages of the stars and the age of the universe.

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20.

Which one of the following, ██ █████ ████ █████ ██ ███████ ███ ███ ████████████ █████████ ██ ███ ██████ █████████ ████ █████ ████ ███████ ███ ███████ ████████ ███████ ███ ████ ██ █████ █████ ███ ███ ███ ██ ███ █████████

a

The stars are ███ ██████ ███████ ███ ██████████ ██ ███ █████████
Incorrect. The astronomer's conclusion that her estimates resolve the discrepancy between the ages of the stars and the age of the universe tells us that, based on her estimates, the stars are at most as old as the universe. But nothing in her conclusion suggests that the stars are the oldest discovered objects in the universe, nor does knowing (A) help explain why her estimates resolve the apparent discrepancy.
2%
b

The younger the ████████ ███ ███ ████ ██████ █████ ██ ██ ██████ ██ █████
Incorrect. We don't need the universe to be younger. We need the stars themselves to be younger. (B) doesn't help explain how the astronomer's estimates resolve the apparent discrepancy.
5%
c

The brighter a ████ ███ ███ ███████ ██ ███
Correct. This is pretty much exactly what we pre-phrased. The astronomer tells us that her estimates indicate that the stars are much brighter than was previously thought, and concludes that this somehow resolves the apparent discrepancy between the ages of the stars and the age of the universe — i.e., this somehow suggests that the stars are younger than was previously thought. (C) exactly bridges the gap between the astronomer's premise and her conclusion.
67%
d

How bright celestial ███████ ██████ ██ ██ ███████ ██ ███ ███ ████ ████ ███ ████████ ████ ████
Incorrect. We're not interested in how distance affects the perceived brightness of a celestial object. We're interested in how the astronomer's new estimates of these stars' distance, and therefore of their brightness, affect estimates of their age. (D) doesn't tell us how either distance or brightness relates to age — it just talks about how distance is related to (perceived) brightness. So (D) doesn't explain how the astronomer's new estimates resolve the previous discrepancy.
24%
e

New telescopes allow ███████████ ██ ███ █ ███████ ██████ ██ ███████ ██████
Incorrect. (E) doesn't matter to the discussion of the age of these specific stars.
2%

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