PT159.S2.P3.Q16

PrepTest 159 - Section 2 - Passage 3 - Question 16

Hide analysis
P1

Since 1929, cosmologists have known that the universe is expanding. █████ █████████ ████ ███████ ████ ███ █████████ ██ ███████ ██ ███ ██████████ ███ ███████ ████ ███████ ███ ██ ███ ████ ██████ ███████████ ███ ███ ██ ███████ ███ ███████ ██ █████████ ███ █████████ ██ █████████ █████ █████ ██ ███████████ ██ █████ █████████ ███ ████████ ██████████ ████ ████ ████ ███████ ████ █████████ █████ ████████ █████ ████ ███ █████████ ██ ███ ████████ ██ ████████ █████████████

Unexpected phenomenon · Expansion of universe is accelerating, rather than slowing down
P2

████████████ ████ ████████ ███ ████████████ ███ ███ ███████████ █████████ ██ ███ █████████ ████ ███ █ █████████ ██ ███ ███████ ██████████ ██ ███ █████████ ███

Two potential explanations · Both challenge current understanding of the universe
███ █████ ███ ████ ██████ ████████ ██████ ██████ █ ████ ██ █████ ███████ ████ ██████ █████ ██████ ██ ████████ ██████ ███████ ██ ███ █████████ ██ ███ ███ ████ ████ █████████ ███ ████ ███ ████ ███████ ██████████ ████ ██ █████ ████ ███████ ███ █ ████████ ███ ██████ ██ ███ ██████████ █████████ ███ ████████ ███████ ██ ███ ████ ██████ ██████ ██████████ ████ ████ ██████ ██ ██ ████████ ████ ██ ███ ██████ ██ ██████ ███ ████ ██ ██████ █ ████████ █████████ ███ █████ ██████ █████ ████ ██ █████ ████ ████████ ████████ ████ █ ████████ ██ █████████ █████ ██ ███████ ███ █████████████ ██████████ ██ █████ ██ ███████ ███ ███ ████████ ██ ███ █████████ █████ ███ ███ ████████ ██ █████ █████████ ███ ██████ ██ ███████████ ████ ███████████ █████ ████ ███ ████████ ██ ██ ████ ██████████ ███ ██████████ ████████ ████ ███ ██ ████ █████ ██ ████ ██████ ███ █████████████

Explanation 1 · Dark energy
The idea of energy stretching space dates back to Einstein. There’s some support for this theory.
P3

████ ████████████ █████████ ████ ███ ████ ██████ ████ ██████ ███ ███████████ █████████ ██ ███ ████████ ██ ███████ ██ █ █████ ██ █████████ ██████████ ████████ ██████████ ████ █████ ███ ████ ███████ █████ ██████ ██ ███████ ██████████ ███ █████████ ████████ █████ ████ ███████ █████████ █████████ ███████ ██ ███ ███ ██ ██████████ █ ███████ ████ █████████ █ ████████ ██████ ███████ █████████ ██ ███ ████ ██████ ██████████ ████ ██████ ██████ ███████████ ███ ████ ██████ ██ █████ █████ ██████ ████████ ███

Potential origin of dark energy · Created by “virtual” particles
The particles pop in and out of existence, creating “vacuum” energy.
██████████████ ████████ █████ ██ █ █████ ███████████ ███████ ███ █████████ █████ ██ ███ ██████ ██████ ███ ███ ██████ ██ ██████ ██████ ██ ███████ ███ ███████████ ██████████

Inconsistent evidence · “Vacuum” energy theory of dark energy not supported
P4

████ ███████████ ██ ███ ██ █████ ███ ███ ██████ ███████ ██ ██ ████ ███ ██████ ███ ███████ ██ ████ ██████ ██ ████ ████████ ██ ████████ ███ ███████████ █████████ ██ ███ ████████ ██ ████████ ████ ██████ ████ █████ ████████████████████ ██ █████████████████████ ██ ██████ █████ ██ ██████████ ███████ ██████ ██ ██████████ █████████ ███

Explanation 2 · Gravity doesn’t work as predicted across large distances
████ █ ██████ ██ ███ ██████ ██ ███████ █████ ██ █████ ████████ ███ ██ █████ ██████████ ████ ███████████ ████████████ ███ ███ ███ ███████ █████ ████ ██ █████ ██████████ ███████ █████ ████████████ █████ ██ ██████ ██ ███ ███ █████ ███████ ████ █████ ████████ ██ ██ █████████ ███ ███ ███████ ███████ █████ ██ █████ ████ ████ ██████ ███ ██ ██████ ██ ████ ████ ███ ████ ██████ ███████

Additional details about Explanation 2 · Theory is radical and might be easier to test than dark energy theory
Passage Style
Phenomenon-hypothesis (RC)
Show answer
16.

The passage indicates which one ██ ███ ██████████

a

Quantum mechanics reveals ████ ███ █████████ ██████ ██ ███ ████████ ██████

Supported by the comment that our knowledge that the "vacuum" has some particles is "thanks to quantum mechanics."

50%
b

Prior to 1929, ███████████ ████████ ████ ███ ████████ ███ ████████ ██ █████

Not supported. Although we know that cosmologists have known since 1929 that the universe is expanding, this doesn't imply that they believed it was infinite before 1929. It could be that they thought it was shrinking or just not changing in size.

2%
c

Supernovas may be ██████ ███████████ ███ ███ █████████ ██ ███ █████████

Although supernovas are mentioned in connection with how scientists tried to measure or observe the expansion of the universe, this isn't evidence that supernovas cause the expansion. The two explanations for the expanding universe (dark energy and weird gravity) don't involve supernovas.

5%
d

Dark energy was █████ ████████ ██ ████████ ██ █████

Einstein proposed the idea of a constant pressure on the universe in 1917. But this constant pressure isn't "dark energy." This constant pressure may be exerted by dark energy, but that doesn't make the pressure itself the same thing as dark energy.

34%
e

Virtual particles are ███ ███████ ██ ███ ███████ ██████ ██ ███████████

The author never comments on virtual particles and how they might relate to Einstein's general theory of relativity. Einstein's theory of relativity is mentioned in connection with the second explanation, but not in connection with dark energy or virtual particles.

8%

Answer five questions and we'll estimate your score.

It takes about five minutes.

Take the free diagnostic
More free LSAT prep: Sample LSAT questions Full-length diagnostic & practice test All free LSAT resources

Confirm action

Are you sure?