Until recently many astronomers believed that asteroids travel about

Question

Until recently many astronomers believed that asteroids travel about the solar system unaccompanied by satellites. These astronomers assumed this because they considered asteroid-satellite systems inherently unstable. Theoreticians could have told them otherwise: even minuscule bodies in the solar system can theoretically have satellites, as long as everything is in proper scale. If a bowling ball were orbiting about the Sun in the asteroid belt, it could have a pebble orbiting it as far away as a few hundred radii (or about 50 meters) without losing the pebble to the Sun’s gravitational pull.

Observations now suggest that asteroid satellites may exists not only in theory but also in reality. Several astronomers have noticed, while watching asteroids pass briefly in front of stars, that something besides the known asteroid sometimes blocks out the star as well. Is that something a satellite? The most convincing such report concerns the asteroid Herculina, which was due to pass in front of a star in 1978. Astronomers waiting for the predicted event found not just one occultation, or eclipse, of the star, but two distinct drops in brightness. One was the predicted occultation, exactly on time. The other, lasting about five seconds, preceded the predicted event by about two minutes. The presence of a secondary body near Herculina thus seemed strongly indicated. To cause the secondary occultation, an unseen satellite would have to be about 45 kilometers in diameter, a quarter of the size of Herculina, and at a distance of 990 kilometers from the asteroid at the time. These values are within theoretical bounds, and such an asteroid-satellite pair could be stable.

With the Herculina event, apparent secondary occultations became “respectable”—and more commonly reported. In fact, so common did reports of secondary events become that they are now simply too numerous for all of them to be accurate. Even if every asteroid has as many satellites as can be fitted around it without an undue number of collisions, only one in every hundred primary occultations would be accompanied by a secondary event (one in every thousand if asteroid satellites system resembled those of the planets).

Yet even astronomers who find the case for asteroid satellites unconvincing at present say they would change their minds if a photoelectric record were made of a well-behaved secondary event. By “well-behaved” they mean that during occultation the observed brightness must drop sharply as the star winks out and must rise sharply as it reappears from behind the obstructing object, but the brightness during the secondary occultation must drop to that of the asteroid, no higher and no lower. This would make it extremely unlikely that an airplane or a glitch in the instruments was masquerading as an occulting body.   1 
 1. Which one of the following best expresses the main idea of the passage?

(A) The observation of Herculina represented the crucial event that astronomical observers and theoreticians had been waiting for to establish a convincing case for the stability of asteroid-satellite systems.
(B) Although astronomers long believed that observation supports the existence of stable asteroid-satellite systems, numerous recent reports have increased skepticism on this issue in astronomy.
(C) Theoreticians’ views on the stability of asteroid-satellite systems may be revised in the light of reports like those about Herculina.
(D) Astronomers continue to consider it respectable to doubt the stability of asteroid-satellite systems, but new theoretical developments may change their views.
(E) The Herculina event suggests that theoreticians’ views about asteroid-satellite systems may be correct, and astronomers agree about the kind of evidence needed to clearly resolve the issue.

2 
 2. Which one of the following is mentioned in the passage as providing evidence that Herculina has a satellite?

(A) the diameter of a body directly observed near Herculina
(B) the distance between Herculina and planet nearest to it
(C) the shortest possible time in which satellites of Herculina, if any, could complete a single orbit
(D) the occultation that occurred shortly before the predicted occultation by Herculina
(E) the precise extent to which observed brightness dropped during the occultation by Herculina

3 
 3. According to the passage, the attitude of astronomers toward asteroid satellites since the Herculina event can best described as

(A) open-mindedness combined with a concern for rigorous standards of proof
(B) contempt for and impatience with the position held by theoreticians
(C) bemusement at a chaotic mix of theory, inadequate or spurious data, and calls for scientific rigor
(D) hardheaded skepticism, implying rejection of all data not recorded automatically by state-of-the-art instruments
(E) admiration for the methodical process by which science progresses from initial hypothesis to incontrovertible proof

4 
 4. The author implies that which one of the following was true prior to reports of the Herculina event?

(A) Since no good theoretical model existed, all claims that reports of secondary occultations were common were disputed.
(B) Some of the reported observations of secondary occultations were actually observations of collisions of satellites with one another.
(C) If there were observations of phenomena exactly like the phenomena now labeled secondary occultations, astronomers were less likely than to have reported such observations.
(D) The prevailing standards concerning what to classify as a well-behaved secondary event were less stringent than they are now.
(E) Astronomers were eager to publish their observations of occultations of stars by satellites of asteroids.

5 
 5. The information presented in the passage implies which one of the following about the frequency of reports of secondary occultations after the Herculina event?

(A) The percentage of reports of primary occultations that also included reports of secondary occultations increased tenfold compared to the time before the Herculina event.
(B) Primary occultations by asteroids were reported to have been accompanied by secondary occultations in about one out of every thousand cases.
(C) The absolute number of reports of secondary occultations increased tenfold compared to the time before the Herculina event.
(D) Primary occultations by asteroids were reported to have been accompanied by secondary occultations in more than one out of every hundred cases.
(E) In more than one out of every hundred cases, primary occultations were reported to have been accompanied by more than one secondary occultation.

6 
 6. The primary purpose of the passage is to

(A) cast doubt on existing reports of secondary occultations of stars
(B) describe experimental efforts by astronomers to separate theoretically believable observations of satellites of asteroids from spurious ones
(C) review the development of ideas among astronomers about whether or not satellites of asteroids exist
(D) bring a theoretician’s perspective to bear on an incomplete discussion of satellites of asteroids
(E) illustrate the limits of reasonable speculation concerning the occultation of stars

7 
 7. The passage suggests that which one of the following would most help to resolve the question of whether asteroids have satellites?

(A) a review of pre-1978 reports of secondary occultations
(B) an improved theoretical model of stable satellite systems
(C) a photoelectric record of a well-behaved secondary occultation
(D) a more stringent definition of what constitutes a well-behaved secondary occultation
(E) a powerful telescope that would permit a comparison of ground-based observations with those made from airplanes

gmat1393 · Accepted Answer

1. Which one of the following best expresses the main idea of the passage?

The passage states that Herculina is an important event, which helped in solidifying the Theoretician's views and the kind of evidence needed by astronomers to resolve the issue.

Options A and E mention the importance of Herculina event, but option A is extreme

Choice E is correct.

2. Which one of the following is mentioned in the passage as providing evidence that Herculina has a satellite?

Following is a except from para 2 of the passage.
 
Based on this we can narrow it down to option D.

3. According to the passage, the attitude of astronomers toward asteroid satellites since the Herculina event can best described as

In para 3 it is mentioned that Herculina event is "respectable" and para mentions the about the possibility of photoelectric record evidence.
Using this, we can say that Choice A is correct.

4. The author implies that which one of the following was true prior to reports of the Herculina event?

Used POE for this one.

(A) Since no good theoretical model existed, all claims that reports of secondary occultations were common were disputed.  -- Not mentioned 
(B) Some of the reported observations of secondary occultations were actually observations of collisions of satellites with one another.  -- Cant be inferred 
(C) If there were observations of phenomena exactly like the phenomena now labeled secondary occultations, astronomers were less likely than to have reported such observations.  -- Hold 
(D) The prevailing standards concerning what to classify as a well-behaved secondary event were less stringent than they are now.  -- No criteria mentioned 
(E) Astronomers were eager to publish their observations of occultations of stars by satellites of asteroids.  -- Never mentioned 
 
 5. The information presented in the passage implies which one of the following about the frequency of reports of secondary occultations after the Herculina event?

(D) Primary occultations by asteroids were reported to have been accompanied by secondary occultations in more than one out of every hundred cases. -- Clearly Mentioned in para 3. Remaining choices are inconsistent with the info in passage.

Sajjad1994 · Answer

Explanation

5. The information presented in the passage implies which one of the following about the frequency of reports of secondary occultations after the Herculina event?

Explanations

Paragraph 4  says that reports of secondary occultations grew so common after the Herculina event that they’re now too numerous for all to be correct. Why? Because even if every asteroid has the highest plausible number of satellites,  “only one in every hundred primary occultations would be accompanied by a secondary event.”  So  (D) must be correct:  Since the Herculina event, reports of secondary events have been occurring at a rate greater than this maximum plausible rate of one in every one hundred cases.

(A) and (C)  simply can’t be concluded based on the passage’s information. We don’t know how many reports of primary occultations have included secondary occultations, or how many reports of secondary occultations there are or were, so we can’t calculate the increase of either.

(B)  distorts the last parenthetical clause of  paragraph 4 , which describes what would be the case if asteroid-satellite systems resembled planet-satellite systems, not what is in fact the case on actual reports of secondary occultations.

(E)  is beyond the scope. The passage never mentions any report containing more than one secondary occultation.

• When you come across numbers in the question stem, make sure you understand the author’s purpose in using them—in this case, to give you the highest reasonable limit for the number of secondary occultations one would expect to occur.

Answer: D

Hope it helps

Sajjad1994 · Answer

Explanation

4. The author implies that which one of the following was true prior to reports of the Herculina event?

Explanation

(C)  gets to the heart of the matter. The first sentence of  paragraph 4 says  that after the Herculina event secondary occultations became  “‘respectable’—and more commonly reported.”  This implies that before the Herculina event secondary occultations weren’t considered respectable, and so weren’t commonly reported.

(A)  Au contraire.  Paragraph 1  indicates that a good theoretical model of asteroid-satellite systems did exist prior to the Herculina event.

(B)  The author never implies that satellite collisions were mistaken for occultations. There’s no speculation on what, other than an actual satellite, might have occasioned the rare reported observations of secondary events before the Heruclina event.

(D)  Prior to the Herculina event, it wasn’t even respectable to report secondary events. The issue of what constitutes a  “well-behaved”  event only arises later (in  Paragraph 5 ).

(E)  Au contraire aussi. Prior to the Herculina event, it wasn’t respectable to report the observation of a secondary event.

Answer: C

Hope it helps

Sajjad1994 · Answer

Explanation

1. Which one of the following best expresses the main idea of the passage?

Explanation.

This passage is about the existence of asteroid-satellite systems: astronomers used to doubt their existence, but now recognize that they are theoretically possible, and are looking for definitive proof.  (E)  correctly notes that theoreticians were on to the existence of asteroidsatellite systems before astronomers were. Moreover, (E)’s idea that astronomers agree on what would be conclusive proof echoes the final paragraph.

(A)  focuses on a detail—the Heruclina event. But the passage is about asteroid-satellite systems in general, not just about the Herculina observations.

(B)  Au contraire. The first sentence of the passage tells us that astronomers  “long believed”  that stable asteroid-satellite systems weren't possible; furthermore, skepticism about the existence of such systems has decreased.

(C)  Au contraire aussi. The Herculina event supported the theoreticians’ views about asteroid-satellite systems. Besides, like  (A) , this choice is focused on a detail.

(D)  is a  “half-right, half-wrong”  choice. Skeptical astronomers aren’t waiting for new theoretical models, but for physical evidence in the form of photoelectric records.

Answer: E

Hope it helps

auradediligodo · Answer

Hi everyone,
Solved this one in 14 minutes.

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P1

Paragraph one tells us that astronomers do not believe in the relation asteroid-satellite because they think of it as an unstable relation. 
Theoreticians on the other hand believe that such relation can exist if everything is proportionated.

Brief summary:  Astronomers' and theoreticians' point of view

P2

Paragraph 2 suggests that the asteroid-satellite relation might be true also in reality. This fact was suggested by an observation of the asteroid Herculina. Such observation led to spot 2 occultations of the star: one by herculina and another probably by another object (maybe a satellite)

Brief summary:  An observation supports the relation asteroid-satellite

P3

Since the observation mentioned in P2, may more observations were made but, according to the author, such observations are too many to be true. The author states that a secondary event can be seen only once every 100 cases (or once every 1000 cases if we are talking about planets).

Brief summary:  too many observation for the relation to be true

P4

Paragraph 4 gives us the new astronomers' point of view. They would be convinced if they were given photoelectric record of well behaved secondary event. Well behaved means that certain parameters must be convincing.

Brief summary:  Astronomers are ready to change their mind if given the right evidence

Main point

The main point is to see how astronomers change their mind about the relation between asteroids and satellites

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1. Which one of the following best expresses the main idea of the passage?

Pre-thinking

Main point question

Refer to main point above

(A) The observation of Herculina represented the crucial event that astronomical observers and theoreticians  had been waiting for to establish a convincing case for the stability of asteroid-satellite systems. 
 Still not convincing after herculina's observation

(B) Although astronomers long believed that observation supports the existence of stable asteroid-satellite systems, numerous recent reports  have increased skepticism  on this issue in astronomy.
 Skepticism did not increase

(C) Theoreticians’ views on the stability of asteroid-satellite systems may be revised in the light of reports like those about Herculina.
 theoreticians' views are in line with the Herculina observation

(D) Astronomers continue to consider it   respectable   to doubt the stability of asteroid-satellite systems, but new theoretical developments may change their views.
 "With the Herculina event, apparent secondary occultations became “respectable”—and more commonly reported."
Respectable is used in this context. 
 
  (E)   The Herculina event suggests that theoreticians’ views about asteroid-satellite systems may be correct, and astronomers agree about the kind of evidence needed to clearly resolve the issue.
 In line with pre-thinking

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2. Which one of the following is mentioned in the passage as providing evidence that Herculina has a satellite?

Pre-thinking

Detail question

Per P2: " Several astronomers have noticed, while watching asteroids pass briefly in front of stars, that something besides the known asteroid sometimes blocks out the star as well."

(A) the  diameter  of a body directly observed near Herculina
 Not in line with pre-thinking

(B) the distance between Herculina and planet nearest to it
 out of scope

(C) the shortest possible time in which satellites of Herculina, if any, could complete a single orbit
 out of scope

(D)   the occultation that occurred shortly before the predicted occultation by Herculina
 in line with pre-thinking

(E) the precise extent to which observed brightness dropped during the occultation by Herculina
 This information comes from the last paragraph in which astronomers require well behaved observations.  This is a typical example of out of context answer

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3. According to the passage, the attitude of astronomers toward asteroid satellites since the Herculina event can best described as

Pre-thinking

Detail question

Per P3
"With the Herculina event, apparent secondary occultations became “respectable”—and more commonly reported."
Per P4
"astronomers who find the case for asteroid satellites unconvincing at present say they would change their minds if a photoelectric record were made of a well-behaved secondary event. "

(A)   open-mindedness combined with a concern for rigorous standards of proof
 In line with pre-thinking

(B)  contempt for and impatience  with the position held by theoreticians
 Not in line with pre-thinking

(C)  bemusement at a chaotic mix of theory, inadequate or spurious data , and calls for scientific rigor
 Not in line with pre-thinking

(D) hardheaded  skepticism , implying rejection of all data not recorded automatically by state-of-the-art instruments
 Not in line with pre-thinking

(E)  admiration  for the methodical process by which science progresses from initial hypothesis to incontrovertible proof
 Not in line with pre-thinking

-------------------------------------------------------------------------------------

4. The author implies that which one of the following was true prior to reports of the Herculina event?
  Pre-thinking

Inference question

An inference that the author makes is related to P3.
"With the Herculina event, apparent secondary occultations became “respectable”—and more commonly reported."
We can infer that:
#1 secondary occultations were not respectable
#2 secondary occultations were not commonly reported

(A) Since no good theoretical model existed, all claims that reports of secondary occultations were common were disputed.
 All is too extreme

(B) Some of the reported observations of secondary occultations were actually observations of collisions of satellites with one another.
 Cannot be inferred

(C)   If there were observations of phenomena exactly like the phenomena now labeled secondary occultations, astronomers were less likely than to have reported such observations.
 In line with pre-thinking. Inference #2

(D) The prevailing standards concerning what to classify as a well-behaved secondary event were less stringent than they are now.
 . Inconsistent

(E) Astronomers  were eager  to publish their observations of occultations of stars by satellites of asteroids.
 Cannot be inferred. Opposite

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5. The information presented in the passage implies which one of the following about the frequency of reports of secondary occultations after the Herculina event?
  Pre-thinking

Inference question

Refer to P3.
Per P3 we know that too many observations were made to be true.

(A) The percentage of reports of primary occultations that also included reports of secondary occultations increased tenfold compared to the time before the Herculina event.
 Since we don't have data about observations prior to that event we cannot conclude such statement
"With the Herculina event, apparent secondary occultations became “respectable”— and more commonly reported ."
From this statement we can infer that prior to herculina's observation there were other observations but they were not reported.

(B) Primary occultations by asteroids were reported to have been accompanied by secondary occultations in about one out of every thousand cases.
 This answer choice is inconsistent. We know that this condition is valid only for planets

(C) The absolute number of reports of secondary occultations increased tenfold compared to the time before the Herculina event.
 Same reasoning for A

(D)   Primary occultations by asteroids were reported to have been accompanied by secondary occultations in more than one out of every hundred cases.
 Option D is the correct answer. In paragraph 3 we are given that at maximum we would see a secondary event in every 100 cases. We are also given that the observations made were far too many. We can therefore infer that more than 1 observation every 100 observations of such event were made.

(E) In more than one out of every hundred cases, primary occultations were reported to have been accompanied  by more than one  secondary occultation.
 Out of scope

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6. The primary purpose of the passage is to
  Pre-thinking

Main point question

Refer to main point and summaries above

(A) cast doubt on existing reports of secondary occultations of stars
 Not in line with pre-thinking

(B) describe experimental efforts by astronomers to separate theoretically believable observations of satellites of asteroids from spurious ones
 Not in line with pre-thinking

(C)   review the development of ideas among astronomers about whether or not satellites of asteroids exist
 in line with pre-thinking

(D)   bring a theoretician’s perspective   to bear on an incomplete discussion of satellites of asteroids
 Not in line with pre-thinking

(E)  illustrate the limits  of reasonable speculation concerning the occultation of stars
 Not in line with pre-thinking

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7. The passage suggests that which one of the following would most help to resolve the question of whether asteroids have satellites?
  Pre-thinking

Inference question

According to the last paragraph if we were given photoelectric records of such event, we would have strong proof

(A) a review of pre-1978 reports of secondary occultations
 Not in line with pre-thinking

(B) an improved theoretical model of stable satellite systems
 Not in line with pre-thinking

(C)   a photoelectric record of a well-behaved secondary occultation
 in line with pre-thinking

(D) a more stringent definition of what constitutes a well-behaved secondary occultation
 Not in line with pre-thinking

(E) a powerful telescope that would permit a comparison of ground-based observations with those made from airplanes
 Not in line with pre-thinking

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It is a good day to be alive!

Sajjad1994 · Answer

Explanation

6. The primary purpose of the passage is to

Explanation

(A)  Much of the passage describes how reporting  “secondary occultations”  has become respectable.

(B)  deals only with information in paragraph 5. Moreover,  (B) ’s distinction between  “spurious”  and  “theoretically believable”  observations isn’t made in the passage.

(C)  is right on the money: the author’s primary purpose is to trace the development of ideas among astronomers concerning the existence of asteroid-satellite systems.

(D)  The author isn’t trying to bring a  “theoretician’s perspective”  to the discussion; instead, he’s primarily interested in how experimental results enlighten the discussion.

(E)  is easy to eliminate, because it never even mentions asteroid satellites. Moreover, there’s no attempt to limit speculation about occultation.

Answer: C

Sajjad1994 · Answer

Explanation

3. According to the passage, the attitude of astronomers toward asteroid satellites since the Herculina event can best described as

Explanation

The attitude of astronomers since the Herculina event is discussed in  paragraphs 4 and 5. Paragraph 4  says the Herculina event made secondary sightings  “respectable” —i.e many astronomers came to accept the possible existence of asteroid-satellite systems.  Paragraph 5  indicates that even astronomers who are still doubters would be convinced by the right kind of evidence. As  (A)  puts it, astronomers who were skeptical of the existence of asteroid-satellites have become more open-minded, although many are still awaiting proof.

(B)  describes the attitude of many astronomers prior to the Herculina event.

(C)  There’s no  “chaotic mix of theory”  relating to asteroid satellites;  paragraph 1  indicates that a single, simple theory supports their existence. Further, the passage doesn’t say that any data is  “spurious.”

(D)  is too negative. Many astronomers already believe that asteroid satellites exist. The skeptics are merely looking for one particular kind of evidence; they aren’t rejecting  “all data not recorded automatically by state-of-the-art instruments.”

(E)  There’s nothing in the passage about admiration for the scientific process, nor has there been  “incontrovertible proof”  of anything.

Answer: A

Sajjad1994 · Answer

Passage Summary

Topic and Scope

Asteroids; specifically whether or not it’s possible for asteroids to have satellites.

Purpose and Main Idea

The author examines the state of the evidence for asteroid satellites. While observations of “secondary occultations” have led some astronomers to accept the existence of such satellites, others remain unconvinced and are looking for specific further evidence (“well-behaved” secondary events).

Paragraph Structure

Paragraph 1  introduces the topic, saying that while most astronomers used to think it was impossible for asteroids to have satellites, theoreticians knew all along that such a thing was possible.

Paragraph 2  supports the theoreticians; observations have led many astronomers to believe that asteroids can have satellites, because when asteroids pass in front of stars,  “something besides the known asteroid sometimes blocks out the star as well.”

Paragraph 3  describes the  “most convincing ... report”  of an asteroid that might have a satellite. When the asteroid Herculina passed in front of a star, the occultation was preceded by another occultation, which led astronomers to believe that a satellite orbiting the asteroid had also passed in front of the star.

Paragraph 4  notes that, after the Herculina event, reports of secondary occultations became  “respectable,”  but warns that such reports have grown so numerous that they can’t possibly all be accurate.

Paragraph 5  concludes by saying that even astronomers who remain skeptical would be convinced by a  “photoelectric record”  of a  “well-behaved”  secondary occultation of a star, one definitely caused by a body accompanying an asteroid.

Sajjad1994 · Answer

7. The passage suggests that which one of the following would most help to resolve the question of whether asteroids have satellites?

Explanation

Based on  paragraph 5 , you can expect the answer to have something to do with the photoelectric record.  (C)  would provide the hard physical evidence we need; a photoelectric record of a  “well-behaved”  secondary event is exactly what skeptical astronomers say  “would change their minds.”

(A)  The existence of such early reports is only hinted at, and the clear implication is that nobody took them very seriously.

(B)  The author never implies that there’s anything wrong with the original theoretical model.

(D)  is just a more refined abstraction—it doesn’t constitute the kind of physical proof needed to resolve the question.

(E)  distorts the passage’s final sentence, which suggests that airplanes passing in front of the instruments might be responsible for some observations of secondary events.

Answer: C

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Until recently many astronomers believed that asteroids travel about

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