Unlike Mercury and Mars, Venus has a dense, opaque atmosphere that

Question

Unlike Mercury and Mars, Venus has a dense, opaque atmosphere that prevents direct observation of its surface. For years, surface telescopes on Earth could glean no information about the surface of Venus. In 1989, the Magellan probe was launched to do a five-year radar-mapping of the entire surface of Venus. The data that emerged provided by far the most detailed map of the Venusian surface ever seen.

The surface shows an unbelievable level of volcanic activity: over one hundred large shield volcanoes, many more than Earth has, and a solidified river of lava longer than the Nile. The entire surface is volcanically dead, with not a single active volcano. This surface is relatively young in planetary terms, about 300 million years old. The whole surface, planet-wide, is the same age: the even pattern of craters, randomly distributed across the surface, demonstrates this.

To explain this puzzling surface, Turcotte suggested a radical model. The surface of Venus, for a period, is as it is now, a surface of uniform age with no active volcanism. While the surface is fixed, volcanic pressure builds up inside the planet. At a certain point, the pressure ruptures the surface, and the entire planet is re-coated in lava in a massive planet-wide outburst of volcanism. Having spent all this thermal energy in one gigantic outpouring, the surface cools and hardens, again producing the kind of surface we see today. Turcotte proposed that this cycle repeated several times in the past, and would still repeat in the future.

To most planetary geologists, Turcotte's model is a return to catastrophism. For two centuries, geologist of all kinds fought against the idea of catastrophic, planet-wide changes, such as the Biblical idea of Noah's Flood. The triumph of gradualism was essential to the success of geology as a serious science. Indeed, all features of Earth's geology and all feature of other moons and planets in the Solar System, even those that are not volcanically active, are explained very well by current gradualist models. Planetary geologists question why all other objects would obey gradualist models, and only Venus would obey a catastrophic model. These geologists insist that the features of Venus must be able to be explained in terms of incremental changes continuously over a long period.

Turcotte, expecting these objections, points out that no incremental process could result in a planet-wide surface all the same age. Furthermore, a slow process of continual change does not well explain why a planet with an astounding history of volcanic activity is now volcanically dead. Turcotte argues that only his catastrophic model adequately explains the extremes of the Venusian surface.    1  
 1. The author implies which of the following about Geology as a science?

A. its legitimacy as a scientific discipline is not well established
B. its proper field is Earth, and therefore its analyses of other planets and moons is more speculative
C. it did not find, in previous religious models of the Earth, a sound basis for analytical theories
D. it can deduce everything about the surface of Mercury purely from Earth-based observations
E. its success derives from surviving exposure to major catastrophes

2  
 2. Which of the following does the passage imply about the surface of Earth's Moon

A. it is not a proper object for geological investigation
B. volcanic activity in the past caused sudden changes
C. most of the features can be best explained by a single all-encompassing event
D. the uneven pattern of cratering indicates different regions of surface are different ages
E. the core of the Moon has no accumulated thermal pressure

3  
 3. In the context of the passage as a whole, the purpose of the second paragraph is

A. provide substantial support for Turcotte's model
B. suggest systematic flaws in the data provided by the Magellan probe
C. call into question geologist's understanding of how volcanoes develop
D. argue for the presence of several incremental changes over time
E. present a seemingly incongruous set of scientific observations

4  
 4. Which of the following would constitute evidence against Turcotte's model?

A. the success of gradualist models explaining the surface of Mars
B. an even more detailed map of the surface of Venus
C. an even longer river of lava on Io, a moon of Jupiter
D. a few active volcanoes on Ishtar Terra, a continent on Venus
E. a volcano on Earth releasing a massive burst of thermal energy all at once

Carcass · Answer

The passage has completely different questions from the original source. You can find it here at this page. Moreover, it is LSAT passage and NOT GMAT https://magoosh.com/lsat/2017/lsat-practice-quiz/

mikemcgarry · Answer

Dear carcass , I'm happy to respond, my intelligent colleague. :-)

As we often do at Magoosh, we use the same content across different tests, if it's appropriate. There are math problems I have written that appear in our products for the GMAT, the GRE, the SAT, the ACT, and others. If the question is valid for more than one test, there's no reason not to use it for more than one test. This passage was written for the Magoosh GMAT product and is also used in the GRE product and the LSAT product. To tell you the truth, I don't think it's the most LSAT-like passage. We are currently in the process of improving the content in the LSAT product, and I don't know whether this passage will make the final cut, even though it performs exeptionally well in the GMAT product. I guarantee that all of these questions here are questions that are live in our GMAT product. I don't know whether you have a Magoosh GMAT account. These questions posted above can be seen here: Question 1 Question 2 Question 3 Question 4 In the Magoosh GMAT product, questions #1, 2, and 4 are exceptionally strong questions, in terms of the item response statistics. These are not publicly available questions, as I usually post, so if you don't have a Magoosh GMAT account, you will be locked out of access to these questions. Does all this make sense? Mike :-)

targetharvard · Answer

Hi  mikemcgarry ,

I got the second and the fourth question incorrect. I was hoping if you could help me understand, what did I miss out that led to the wrong answer. Ihave presented my understanding for the elimination or selection of each AC in red.

Q2 
Which of the following does the passage imply about the surface of Earth's Moon
A. it is not a proper object for geological investigation  Out of Scope

B. volcanic activity in the past caused sudden changes   There is no information about this with regard to Venus, so cant draw an inference

C. most of the features can be best explained by a single all-encompassing event  I chose this one, because this was the one which was left after eliminating all the choices

D. the uneven pattern of cratering indicates different regions of surface are different ages Though the converse is said for Venus. I am unsure as to how this was deduced for the Moon. The Gradualism Model states that all the other planets and moons keep undergoing gradual change.

E. the core of the Moon has no accumulated thermal pressure Cant be inferred for the moon

Q4

Which of the following would constitute evidence against Turcotte's model?
A. the success of gradualist models explaining the surface of Mars I chose this one as this would go against the catastrophic model which is being advocated by TC

B. an even more detailed map of the surface of Venus Does not really help in proving TC Model is wrong

C. an even longer river of lava on Io, a moon of Jupiter Does not really help in proving TC Model is wrong

D. a few active volcanoes on Ishtar Terra, a continent on Venus Can you please explain how this would go against the TC Model. I can not seem to wrap my head around this one

E. a volcano on Earth releasing a massive burst of thermal energy all at once Inconclusive in proving the TC model as incorrect .

Regards

mikemcgarry · Answer

Dear targetharvard , I'm happy to respond. :-)

You have a most intriguing screenname. :-)

For #2, you correctly eliminated (A), (B), and (E). Let's talk about (C) & (D). Of course, the passage itself says virtually nothing about Earth's Moon. C. most of the features can be best explained by a single all-encompassing event The idea of a " single all-encompassing event " sounds a lot like " catastrophic, planet-wide changes, such as the Biblical idea of Noah's Flood ." This is precisely what geologists have fought most vigorously--the catastrophist model. We are told that, besides possible the special case of Venus, everything else in the Solar System can be explained with the gradualist model. Thus, we know quite clearly this answer is incorrect. D. the uneven pattern of cratering indicates different regions of surface are different ages Your comment: Though the converse is said for Venus. I am unsure as to how this was deduced for the Moon. The Gradualism Model states that all the other planets and moons keep undergoing gradual change. First of all, yes, clearly this is converse for what was said for Venus: same cratering over whole surface means the surface is all the same age, so different patterns of cratering in different places means different areas of surface are different ages. I would say: be very careful about what assumptions you impose on the reading. Consider these two view of Gradualism: (a) All changes in geology can be explained by gradual changes, and all these changes are still happening at the same rate (b) All changes in geology can be explained by gradual changes, even if most changes have come to an end Notice that the passage doesn't address this difference, so we can't say that it definitely means one or the other. In fact, it suggests that both can be true, depending on the planet or moon. (In scientific fact, (a) is true for Earth and (b) is true for the Moon.) Furthermore, why would different surfaces of different ages not be due to gradual changes? Let's say that at some point in the far distant past, the Moon had some surface that was pock-marked by craters during a period when cratering was heavy. Then, the rate of cratering abated. Then the Moon had some big volcanos, that spilled a bunch of lava over some places, covering the craters there. All of these are gradual changes--that is changes dependent on specific local events (one crater, one volcano) happening at different times rather than catastrophic all-at-once events that involve the entire planet or moon. (BTW, in our best understand of astrophysics, this is more or less what happened to the Moon: the darker "seas" of lava and the lighter cratered areas is what is responsible for the dark & light regions that create the "man in the moon" appearance.) Moon.png Overall, (D) is the strongest answer for #2. Now, #4, evidence against Turcotte's model: A. the success of gradualist models explaining the surface of Mars your comment: I chose this one as this would go against the catastrophic model which is being advocated by TC It seems reasonably clear that Turcotte knew that what he was proposing for Venus was an entirely different model that what was explained everything else. Certainly since this was the primary objection to his model, he would have been aware that he was saying, essentially, that the way Venus works is different from the way anything else works. People who propose ideas & models are usually made aware, quite quickly, of the principal objections to that model. Thus, Mars, like everything else in the solar system except Venus, follows the gradualist model. That's no surprise to Turcotte. He is quite specific proposing that Venus is different from everything else, so the fact that Mars is different from Venus is entirely expected. D. a few active volcanoes on Ishtar Terra, a continent on Venus your comment: Can you please explain how this would go against the TC Model. I can not seem to wrap my head around this one Once again, let's get clear on the two models. Catastrophist = geological features are shaped by planet-wide, all-at-once events, big events that act everywhere at the same time Gradualist = geological features are shaped by individual events, different things happening in different places at different times, each affecting only one small part of the surface at a time. Turcotte's theory is that Catastrophism 100% explains Venus' surface. If we have a few volcanos in one particular place on Venus, that's not a planet-wide event, but instead a local event--that would show that the gradualist model is required to explain at least that part of the surface. That's a contradiction. Also, consider this part of the passage: While the surface is fixed, volcanic pressure builds up inside the planet. At a certain point, the pressure ruptures the surface, and the entire planet is re-coated in lava in a massive planet-wide outburst of volcanism . Thus, his model is that no heat escapes during the "fixed surface" phase, and then a lot escapes all at once during the "planetary meltdown" phase--in other words, 0% planet-wide heat-release, and then 100% planet-wide heat release, a catastrophist model. Well, if there are a few volcanoes, they are letting out a small amount of heat at a particular place--in other words, the heat is being released gradually at these sides, rather than all-at-once on the planet-wide scale. That would be a big contradiction of Turcotte's model. Overall, (D) is the strongest answer for #4. Does all this make sense? Mike :-)

chesstitans · Answer

the question 1 sounds like the question type of opinion of author.

new question

All of the following would help support Turcotte’s contention that Venus' geology is quite different from every other geological entity in the solar system EXCEPT

A the size of the volcanoes on Venus
B the absence of oceans to provide erosion and weathering
C the rising temperature of the planet's core
D no natural satellite to induce continuous seismic forces
E a radioactive core that continues to generate great amounts of heat

OA is A

Kezia9 · Answer

Hi Mike,

Can you explain how is option C the best answer for question1?I chose option A.

gmatexam439 · Answer

Dear  mikemcgarry ,

Can you please explain question 1. I got that wrong. Rest were directly infer-able from the passage.

Regards

mikemcgarry · Answer

Dear gmatexam439 & chesstitans , I'm happy to respond.

First of all, I would say that this question is less an "opinion of the author" question and more an inference question. See: Inference on GMAT Reading Comprehension This is a very challenging question, focused primarily on paragraph 4. Here's an analysis of the question: Q1 The author implies which of the following about Geology as a science? A. its legitimacy as a scientific discipline is not well established No. The text says: " The triumph of gradualism was essential to the success of geology as a serious science ." Geology is a serious science, so it is well established. B. its proper field is Earth, and therefore its analyses of other planets and moons is more speculative No. The text says: " Indeed, all features of Earth's geology and all feature of other moons and planets in the Solar System, even those that are not volcanically active, are explained very well by current gradualist models . " It sounds as if the scientific work of geology is on equally firm footing whether we are talking about Earth itself or one of the other planets or moons. Furthermore, the passage implies that " planetary geologists " are just as legitimately scientists as are geologist who study the earth: one is not doing "more real" work than the other. C. it did not find, in previous religious models of the Earth, a sound basis for analytical theories This sound plausible. The text says: " For two centuries, geologist of all kinds fought against the idea of catastrophic, planet-wide changes, such as the Biblical idea of Noah's Flood. The triumph of gradualism was essential to the success of geology as a serious science ." An example of a " religious model of the the Earth " would be an explanation of Earth's features as a result of Noah's Flood , a story from the Bible. Geology had to fight against that and refute that approach before it could be a serious science with legitimate analytical theories. All of this implies that the previous religious-based models were compatible with a serious scientific approach and thus did not provide a sound basis for analytical theories. This is a promising answer. D. it can deduce everything about the surface of Mercury purely from Earth-based observations Too extreme. The text says: " Unlike Mercury and Mars, Venus has a dense, opaque atmosphere that prevents direct observation of its surface ." OK, so this implies that Mercury doesn't have a " dense, opaque atmosphere " and therefore we can do some " direct observation of its surface ." Clearly, we can tell some things about the surface of Mercury simply by looking through Earth-based telescope. Does this mean we can tell everything ? That, for example, sending a probe to Mercury for close-up photos would tell us absolutely nothing that we don't already know from our Earth-based photographs? You see, this one takes a reasonable idea to an absurdly extreme level, so it is wrong. E. its success derives from surviving exposure to major catastrophes No. This is a "word salad" kind of trap answer--it uses words from the passage, so it can trap people simply scanning for relevant words, but the words are put together in a way that states something very different from what the passage implies. Geology examined different models, and had to fight against " catastrophic " models of the Earth and establish " gradualist " models of the Earth. That's true. But Geology itself, the academic discipline, did not have to go through its own catastrophes. Catastrophes were one proposed explanation for Earth's features, an explanation that Geology rejected, but the discipline itself did not experience its own catastrophes. This answer blurs the level of analysis, and confuses what the discipline has studied for what the discipline itself was experiencing. This is wrong. Does all this make sense? Mike

mikemcgarry · Answer

Dear Kezia9 , My friend, for your own benefit, I will point out something ironic. Your post asking for help on question 1 is directly below an extensive post in which I explained Q1 in great detail. If you simply had read the entire thread, you would have seen that your question was already answered, less than 12 hours before you asked it. My friend, you are reaching a point in life in which you have to take more responsibility for the questions you ask. Asking a question when the answer is readily available to you is a sure way to indicate to a manager that he shouldn't trust you or rely on you. This could be a single move that would have devastating consequences on your career advancement. Fortunately, there's no big consequence at the moment, but now is precisely the time to practice tremendous self-responsibility in the question process, so that this is an ingrained habit by the time you are in the professional world. By the time you are in the pressure of the work place, it's too late to try to learn all these good habits that you will need. Ultimately, you are responsible for every aspect of you own education. No one achieve excellence on the GMAT simply by having experts explain things to him. Excellence is the product of exceptional effort and diligence. In this context, I would recommend the habits of excellence . Does all this make sense? Mike

jawele · Answer

Passage summary:
1) Scientists managed to obtain information about Venu's surface
2) A description of findings that are later considered surprising: inactive volcanos and the
same age of the whole surface.
3) Turcotte's hyphotezis to explain the observations. It says that the surface has been
formed by several gigantic outburst of lava that possibl covered the whole surface of the
planet.
4) Disagreement with T's ideas. Although gradualism doesn't fit well, some scientists try
to stretch their idea that perhaps the observations can be explained in terms of incremental
changes.
5) T disagrees with the gradualism theory because it doesn't explain the same age and
volcanic inactivity.

Q1 The author implies which of the following about Geology as a science? Relevant text: The triumph of gradualism was essential to the success of geology as a serious science."
A. its legitimacy as a scientific discipline is not well established its legitimacy has well succeeded
B. its proper field is Earth, and therefore its analyses of other planets and moons is more speculative the passage says it can explain all other but Venus
C. it did not find, in previous religious models of the Earth, a sound basis for analytical theories correct
D. it can deduce everything about the surface of Mercury purely from Earth-based observations reliance on observations about a different planet to explain another is not given
E. its success derives from surviving exposure to major catastrophes could be true, but is not given

Q2 Which of the following does the passage imply about the surface of Earth's Moon Relevant text: Indeed, all features of Earth's geology and all feature of other moons and planets in the Solar System, even those that are not volcanically active, are explained very well by current gradualist models. <...> These geologists insist that the features of Venus must be able to be explained in terms of incremental changes continuously over a long period. <...> Turcotte, expecting these objections, points out that no incremental process could result in a planet-wide surface all the same age.
A. it is not a proper object for geological investigation
B. volcanic activity in the past caused sudden changes
C. most of the features can be best explained by a single all-encompassing event
D. the uneven pattern of cratering indicates different regions of surface are different ages correct
E. the core of the Moon has no accumulated thermal pressure superficial word match

Q3 In the context of the passage as a whole, the purpose of the second paragraph is
A. provide substantial support for Turcotte's model two point of views described
B. suggest systematic flaws in the data provided by the Magellan probe
C. call into question geologist's understanding of how volcanoes develop
D. argue for the presence of several incremental changes over time
E. present a seemingly incongruous set of scientific observations correct

Q4 Which of the following would constitute evidence against Turcotte's model? Relevant text: Turcotte, expecting these objections, points out that no incremental process could result in a planet-wide surface all the same age. Furthermore, a slow process of continual change does not well explain why a planet with an astounding history of volcanic activity is now volcanically dead.
A. the success of gradualist models explaining the surface of Mars no bearing whatsoever; if anything, that would go against his theory
B. an even more detailed map of the surface of Venus
C. an even longer river of lava on Io, a moon of Jupiter
D. a few active volcanoes on Ishtar Terra, a continent on Venus correct because this contradicts some observations that have formed the basis for his theory
E. a volcano on Earth releasing a massive burst of thermal energy all at once that's support

Unlike Mercury and Mars, Venus has a dense, opaque atmosphere that

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GMAT Reading Comprehension (RC) Questions

Unlike Mercury and Mars, Venus has a dense, opaque atmosphere that

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