Objects in the inner solar system - the planets and asteroid belt

Question

New Project RC Butler 2019  -  Practice 2 RC Passages Everyday   
Passage # 102, Date : 23-MAR-2019
 This post is a part of New Project RC Butler 2019 .  Click here for Details

Objects in the inner solar system - the planets and asteroid belt - follow ellipsoid orbits that are predictable in nature. While they may shift over billions of years, on a million-year timescale these objects are relatively easy to model. In contrast, scientists have long debated why small objects beyond Neptune and Pluto tend to have orbits that are circular in nature and irregular on the million year timescale. Most theorized that there must be an elusive “ninth planet” beyond Neptune that had enough mass to deform the orbits of smaller objects in close proximity. However, as telescope technology has increased in complexity, there has been no sign of an additional planet of sufficient size to meet this requirement.

To investigate the cause of these irregularities and find an alternate explanation, Madigan et al. used computer simulations to model the way different objects in the outer solar system moved around the sun. They saw that within the simulation the smaller objects move more quickly than do larger ones. This allowed them to notice a peculiar phenomenon. As the objects move around the sun, pile ups of objects in orbits close to one another occur as smaller objects catch up to bigger ones, causing a gravitational “jostling” effect. This effect causes the usually ellipsoid orbits to deform into the circular ones that scientists have tried to explain for so long. It also leads to the temporary creation of a bigger object that moves more slowly and moves further away from the sun. As the conglomeration breaks up, the now-smaller objects begin to move more quickly are pulled closer to the sun, creating the hypothesized irregularities in the objects’ orbits.   1 
 E 
 1) Which of the following best describes the structure of this passage?

A) A scientific norm is explained and an interpretation of that norm is presented and then rejected.
B) Two theories about a scientific observation are presented and one is rejected as impractical.
C) Two methods for predicting a scientific phenomenon are presented and one is deemed more suitable.
D) A former scientific theory is presented and then rejected before an alternative theory is revealed and confirmed.
E) A scientific problem is introduced, a potential answer is discarded, and an alternative explanation is posed.

2 
 B 
 2) It can be inferred that a large planet as described in passage would

A) move more quickly around the sun than would smaller planetoids.
B) move more slowly around the sun than would smaller planetoids.
C) orbit closer to the sun than would smaller planetoids.
D) explain all deviations in other objects’ orbits.
E) suggest an explanation for gravitational jostling.

3 
 A 
 3) Within the context of the second paragraph, why is it important that large objects move around the sun more slowly than do smaller ones?

A) If there was no difference in the speed at which the objects move, jostling may not occur.
B) Relative speeds directly cause changes in the orbits of objects in the outer solar system.
C) The fact that larger objects move so slowly definitively proves that an additional planet beyond Neptune cannot exist.
D) The differences in speed directly explain the irregularities in the distance between objects in the outer solar system and the sun.
E) Larger objects have more inertia and could distort other objects’ orbits more if they moved more quickly.

Difficulty Level:   650

TaN1213 · Answer

Large planets are mentioned in Paragraph 2 whereas Q2 states Paragraph 1.
Am I missing something for Q2 ?

souvonik2k · Answer

Hi
Large planets can be referred to ''Most theorized that there must be an elusive  “ninth planet”  beyond Neptune that had  enough mass to deform the orbits of smaller objects  in close proximity.'' in 1st paragraph.

globaldesi · Answer

for Q3
Whenever you are asked to interpret the significance of a single sentence or idea within the context of a larger paragraph, remember that you should first look at that sentence or idea by itself before you look at it in context. This question asks why it's important that large objects move more slowly than do smaller ones. In the second paragraph, you are told that "pile ups" of different sizes of objects occur as small objects catch up to larger ones within the same orbit. It's these pile ups that cause the gravitational jostling effect that in turn leads to the circular shape of the orbits. So without the difference in speed, the small objects wouldn't catch up, so the jostling wouldn't occur. This matches answer choice (A).

Among the other answers, (B) and (E) can be eliminated because (even if they are true) there is no evidence in the context of the paragraph. Choice (C) can be eliminated because the jostling effect means that the effect the planet was thought responsible for occurs without the planet, and choice (D) can be eliminated because the speed itself doesn't account for the changes - the jostling caused by the speed accounts for the changes.

tapasgupta · Answer

1) Which of the following best describes the structure of this passage?

A) A scientific norm is explained and an interpretation of that norm is presented and then rejected.  - out of scope
 B) Two theories about a scientific observation are presented and one is rejected as impractical.  - out of scope
 C) Two methods for predicting a scientific phenomenon are presented and one is deemed more suitable.  - out of scope
 D) A former scientific theory is presented and then rejected before an alternative theory is revealed and confirmed.  - Partial scope. No confirmation is done. 
 E) A scientific problem is introduced, a potential answer is discarded, and an alternative explanation is posed.  - that is the main idea of the passage

2) It can be inferred that a large planet as described in paragraph 1 would

A) move more quickly around the sun than would smaller planetoids.  - opposite
 B) move more slowly around the sun than would smaller planetoids.  - as stated in the 1st para
 C) orbit closer to the sun than would smaller planetoids.  - out of scope
 D) explain all deviations in other objects’ orbits.  - out of scope
 E) suggest an explanation for gravitational jostling.  - out of scope

3) Within the context of the second paragraph, why is it important that large objects move around the sun more slowly than do smaller ones?

A) If there was no difference in the speed at which the objects move, jostling may not occur.  - this is the main reason for the same
 B) Relative speeds directly cause changes in the orbits of objects in the outer solar system.  - out of scope
 C) The fact that larger objects move so slowly definitively proves that an additional planet beyond Neptune cannot exist.  - out of scope
 D) The differences in speed directly explain the irregularities in the distance between objects in the outer solar system and the sun   - out of scope
 E) Larger objects have more inertia and could distort other objects’ orbits more if they moved more quickly.  - out of scope

singhss · Answer

Can anyone help explain #2? If this were to show up on an actual exam, my eyes would have gone directly to the first paragraph and stayed there. Its a little misleading for them to tell us to read the first paragraph when the answer is written in the second.

In addition, what in the paragraph suggests that large planets are viewed with the same characteristics in the theory in the first paragraph vs the explanation in the second?

Sajjad1994 · Answer

Your analysis are great, the answer is written explicitly in the second paragraph. This question is not a quality question i think. Timers shows 50% wrong answer and it looks a hard questions if we see only the stats. I can assume that the people who got this question wrong only read first paragraph but not the second, if they try reading second paragraph they would have been get it correct and i think a max 5-10% people get it wrong or perhaps lower than this if they read second paragraph.

This is also weird that they point out 1st paragraph while we cannot answer it correctly unless we read the second paragraph. But it didn't look to me alarming. What is totally against the quality of GMAT questions is that it says  "It can be inferred"  when a GMAT questions ask to infer the answer cannot be found explicitly and we have to infer that based on the text, but here the answer is written explicitly which not good at all. For practicing an inference question this question is not a good choice.

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Objects in the inner solar system - the planets and asteroid belt

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