PrepTest 152 - Section 3 - Passage 4 - Question 23

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Physicists posit that at first our universe was infinitesimally small and infinitely hot and dense. ██ ████ █████████ █ ██████ ██ █████████ ██████ ███████ █████████ ████ ███ ██████ ███ ██ ███ █████ █████████ ██ ██████ ███ █████

Intro topic · Big Bang

Expansion from small, dense, hot universe to larger, cooler universe

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C and C's hypothesis · Big Bang is a recurring event

Support for hypothesis · Multiverse theory

Earlier Big Bangs have occurred outside of the known universe

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Introduce entropy · Idea that disorder increases over time

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Illustration of entropy · Randomly moving objects in room

Room will tend toward disorder each time an object is moved

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Relevance of entropy to Big Bang · Raises questions about pre-Big Bang universe

If the universe tends toward disorder, how did it ever reach its starting state as small and dense in the first place? Seems too orderly, not random

C and C's hypothesis · Most likely starting state for universe is empty space

In other words, it's unlikely that the universe would have started as small and dense purely by chance

G and V's hypothesis · Seemingly empty space can create tiny big bangs

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C and C's hypothesis · Our Big Bang is was a kind of "tiny big bang" in an even larger multiverse

Significance of hypothesis · Reconciles Big Bang theory with entropy

The larger multiverse can be disordered, random, and full of empty space while still containing pockets of matter and energy for big bangs

Passage Style

Phenomenon-hypothesis (RC)

Single position

23.

The claim in the fourth █████████ ████ ██ ███████ █████████ ██ ██████ ██ ████████ █████ █████ █████ ██ ████ ████████ █████████ ██ ███████████ ██ ███

Question Type

Describe organization

Structure

This question asks why we expect the initial condition of the universe to resemble cold, empty space. The second law of thermodynamics is the reason that a small, hot, dense initial condition is less likely (and an initial condition of cold, empty space is more likely). The second law of thermodynamics, which supports the claim in P4, is described in P3.

first paragraph

The information about the second law of thermodynamics supports the claim in P4; P1 doesn’t describe the second law of thermodynamics. Instead, P1 just describes the Big Bang.

second paragraph

The information about the second law of thermodynamics supports the claim in P4; P2 doesn’t describe the second law of thermodynamics. Instead, P2 describes the multiverse and introduces Carroll and Chen’s hypothesis that the Big Bang wasn’t a unique event.

third paragraph

The second law of thermodynamics is the reason that a small, hot, dense initial condition is less likely (and an initial condition of cold, empty space is more likely). The second law of thermodynamics says that entropy naturally increases with time and that there are more ways for a system to be disordered than ordered. Because of this, we expect the initial condition to resemble cold, empty space, so it is the information in P3 that supports this claim made in P4.

37%

fifth paragraph

The information about the second law of thermodynamics supports the claim in P4; P5 doesn’t describe the second law of thermodynamics. P5 gives additional information that resolves the mystery that was introduced in P4 (In other words, P5 explains why we actually saw a small, hot, and dense initial condition), but P5 does not explain why we would expect the initial condition to be cold, empty space.

51%

sixth paragraph

The information about the second law of thermodynamics supports the claim in P4; P6 doesn’t describe the second law of thermodynamics.

PrepTest 152 - Section 3 - Passage 4 - Question 23

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