By 1999, astronomers had discovered 17 nearby stars that are orbited

Question

By 1999, astronomers  had discovered 17 nearby stars that are orbited by planets  about the size of Jupiter

(A) had discovered 17 nearby stars that are orbited by planets

(B) had discovered 17 nearby stars with planets orbiting them that were

(C) had discovered that there were 17 nearby stars that were orbited by planets

(D) have discovered 17 nearby stars with planets orbiting them that are

(E) have discovered that 17 nearby stars are orbited by planets

https://www.nytimes.com/1999/01/10/us/in-new-discoveries-a-planetary-mystery.html

In a stunning run of discoveries  over the last three years , astronomers  have observed  17 nearby stars that appear to be orbited by planets more or less the size of Jupiter. The most recent detection of a planet around a star other than the Sun was described here today.

17 Stars 
 
  (A) CORRECT

(B) Modifier (that)

(C) Meaning

(D) Verb (have discovered); Modifier (that)

(E) Verb (have discovered)

First glance

Three answers begin with  had discovered ; the other two begin with  have discovered . Which one is the correct verb tense for this sentence?

Issues

(1) Verb:  have discovered

Had discovered  is the past perfect tense, used to signal that something took place before something else in the past.  Have discovered  is the present perfect tense, used to denote something that started in the past but is still true or still ongoing in the present.

The time marker  by 1999  indicates that the action took place prior to 1999. As such, the past perfect tense  had discovered  is correct: prior to 1999, the astronomers  had discovered  these stars. Eliminate answers (D) and (E).

(2) Modifier:  that 
 Meaning

It is difficult to choose from among the remaining three choices; this is one of the hardest problems in the Official Guide. Compare the three choices to find the differences:

(A) …17 nearby stars that  are  orbited by planets…

(B) …17 nearby stars with planets orbiting them  that were …

(C) … there were  17 nearby stars that were orbited by planets…

Each of these choices presents a reason not to like it…yet one must be the correct answer! Examine each choice in turn.

The opening part of the sentence uses past perfect, so is it okay to switch to present tense, as choice (A) does?

Past perfect does require either a past time marker or a simple past verb—but the sentence does correctly provide the time marker  by 1999 . The  are  verb, then, is not required to be in the past tense. Does it make sense to have a present tense verb at this point in the sentence? What if it said  were ?

Astronomers had discovered 17 nearby stars that  are  orbited by planets…

Astronomers had discovered 17 nearby stars that  were  orbited by planets…

In the first sentence, the stars were orbited by the planets at the time of discovery and they still are today. That meaning is acceptable.

In the second sentence, the stars were orbited by the planets at some point in the past. Was this still happening at the time of the discovery? Or maybe the astronomers discovered something that was true only prior to the discovery? Or perhaps the action was still occurring at the time of discovery but is no longer going on today? The choice of  were  makes the meaning ambiguous; it’s actually better to use  are . Leave choice (A) in.

Choice (B) contains the noun modifier  that were about the size of Jupiter . What  were about the size of Jupiter : the stars or the  planets ? And when  were  they  the size of Jupiter ?

Noun modifier rules dictate that the modifier be placed as close as possible to the noun that it modifies. In this case, the pronoun  them  (referring to  stars ) is closest to the word  that . The rules allow, however, for an exception: if another noun modifier also modifies the same noun (for instance,  the box of nails, which is on the table… ), then you can have two modifiers in a row, each of which refers back to the original noun. So the  that  modifier could also refer to the  planets . It’s impossible to tell whether the  stars  or the  planets  are  about the size of Jupiter . Answer (B) also introduces ambiguity: when  were  the  stars  or planets  the size of Jupiter ? At the time of discovery? Before? Did they change size later on? Eliminate choice (B) for modifier and meaning issues.

Examine choice (C): The astronomers had discovered that there were 17 nearby stars. When were those stars present? Prior to the discovery? At the time of discovery? What happened later in time—did they disappear? Further, that were orbited creates the same ambiguity: was this true prior to the discovery only, or at the time of the discovery, or at some point after? Did the planets implode? Get pulverized by a meteor? Or maybe the stars were the ones to disappear? Or possibly they are all still there today. Eliminate choice (C) for ambiguity.

The Correct Answer

Correct answer (A) employs the past perfect  had discovered  to indicate something that took place  by 1999 . Further, the modifier and verb choices indicate clearly that the 17 stars continue to be orbited by Jupiter-sized planets today.

EMPOWERgmatVerbal · Answer

Hello  BijayKru !

Thanks for your question! Let's take a look at option C and figure out where the problem lies:

(C) By 1999, astronomers had discovered that there were 17 nearby stars that  were orbited  by planets about the size of Jupiter. 
 
The problem with the verb "were orbited" is that it changes the intended meaning. We know that astronomers discovered the stars and planets in 1999, which was 20 years ago. This sentence also indicates that the planets were orbiting the stars IN THE PAST only, and that they are no longer doing that. That's not the intended meaning we're looking for - we want the reader to know that while astronomers found these stars and planets 20 years ago, they're still doing the same things today. It's not like the planets just suddenly stopped orbiting their stars because we found them - that would be pretty wild!

I hope this helps!

Prowess · Answer

Action started in past but its impact continues in present. So it should be in present tense. Plz help me out.

Posted from my mobile device

EducationAisle · Answer

Hi  Prowess , the crux of  Past Perfect  is:

Past perfect expresses the scenario that an event happened at some point  before  another  event  in the past, or  at some point  before  another  time  in the past .

Here, the sentence under consideration is:

By 1999, astronomers had discovered 17 nearby stars

The event of astronomers discovering 17 nearby stars, happened at some point  before  another  time  (in this case,  1999 ) in the past. Hence, past perfect ( had been ) is the appropriate usage here.

So basically, this particular sentence represents the following scenario:

Past perfect is used to depict an event that has happened within some time-frame before time in the past

Reproducing a similar example given in our book:

Peter started his business in 2012; by 2014, he had established himself well in the business .
 
 Explanation : This sentence is in past perfect ( had established ). If the sentence was  by 2014, Peter had established himself well in the business , the time frame of reference for the event (Peter getting well-established in the business) would basically start in the past (in this case, year  2014 ) and would continue  infinitely  into the past. However, the sentence under consideration also states:  Peter started his business in 2012 . By stating this, the sentence is  restricting  the time frame that it is referring to in the past (in this case,  until year 2012 ).

You can watch our  video  on   Past Perfect . Especially watch out for  Usage -2  explained in the video.

p.s. Our book    EducationAisle Sentence Correction Nirvana    discusses  this scenario of  Past Perfect  . Have attached the corresponding section of the book, for your reference.

GMATNinja · Answer

Yes, we OFTEN use the past perfect with a time marker. As described in  this post  (check out the explanation for choice D), the past perfect tense only makes sense if it describes an action that happened in the distant past, before some other “time marker.” This time marker is often just a later action in simple past tense, but it can also be something like "by 1987."

But do we HAVE to use the past perfect when we see "by + yyyy"? Not necessarily! For a great example of that, check out  this post .

Krishnahelps · Answer

If the sentence had been 'By 1999, astronomers had discovered 17 nearby stars that *have been* orbited by planets about the size of Jupiter", would this have been incorrect?

Also, I can't understand how 'are' is justified here since, it refers to only present but this has been happening?

Please help me out.

Thank you!

GraceSCKao · Answer

Hi,

I am not an expert but since I am reviewing this question, I would like to share some of my thoughts.

For your second question, we can use the present tense "are" to state facts or general truths. Even though most GMAT takers might not be astronomers, we should know that the planets do not suddenly stop orbiting, as Earth does not stop orbiting the sun. So, it should be a fact that the 17 stars are orbited by the planets, so we have a good reason to use "are" in the option (A).

For your first question, I do not think it is a good idea to use the perfect present tense to refer the action of orbiting. First, we can just use the present tense for good reasons shown above. Secondly, the use of perfect present tense actually implies that the action has been completed or finished, but the planets do not stop orbiting the 17 stars.

waytowharton · Answer

GMATNinja   KarishmaB   DmitryFarber

Hi, I was confused between option A and C. I understood the error in simple past tense in option C; however, I would like to understand the impact of difference in meaning in option A and C. As per option A, astronomers discovered 17 stars whereas option C means that astronomers discovered the fact that there were 17 stars. Doesn't, the meaning in option C make more sense than meaning in option A? Can this be a reason to reject option A?

KarishmaB · Answer

waytowharton

While both (A) and (C) might seem to mean the same, option (A) has a more logical meaning and is more direct and clear.

Today morning, he discovered another pathway leading to the river.
Today morning, he discovered that there is another pathway leading to the river.

The two don't necessarily mean the same. In the first sentence, we know that he discovered the path so he was probably walking along and saw a path leading somewhere and followed it and found that it reached the river... 
In the second one he has discovered the information that there is another path. Perhaps someone told him? Has he actually found the path, we don't know. Then can we say that he "discovered" that there is another path? Questionable. Perhaps we should say he found out...

What did the astronomers do? They likely discovered the 17 stars. They were looking into their telescopes and found these stars with planets around them. No one told them about it, that is for sure. Also, "they had discovered that there were 17 nearby stars that had planets" seems to mean that there cannot be more than 17. That of all the nearby stars, 17 had planets. We can certainly not be sure of that, right?

Hence, meaning wise, (A) is much clearer and logical. But I had not delved into the meaning till you asked about it. A fact needs present tense and hence we need 'are', not 'were'. That is why I chose (A) directly and did not give (C) a second thought.

Vordhosbn · Answer

My astrology knowledge is little to none. I didn't know up to this point that planets cannot stop orbiting stars out of no where. Do I need to pick up an astrology book before my test day?

Pankaj0901 · Answer

Why are we assuming that the given sentence is a FACT. It could also be the case that this fact is no longer valid. Stars and planets DO change positions and orbits. It is very much possible that the orbits of these 17 stars and planets today are not in coherence with the findings of discovery before 1999.
Are we eliminating option C, which is free of any errors, ONLY because it conveys a slightly different MEANING than that conveyed by the original sentence?
So, is it correct to conclude that when there are 2 options, free from errors but with a slight difference in meaning, we should immediately go for option A without thinking too much?

ExpertsGlobal5 · Answer

Hello  Pankaj0901 ,

We hope this finds you well.

To answer your query, in this case, the use of the simple present tense is best because the most logical interpretation of the sentence is that at the time of the discovery, at least, the planets  did  orbit those stars.

Further, it is actually our recommendation that if there are two error-free options that differ in meaning, you select the one that aligns with A, assuming the meaning conveyed by Option A is logical and coherent.

As per our SC approach, the meaning conveyed by Option A should be considered the intended meaning, unless:

1. the meaning conveyed is entirely illogical or incoherent

2. Option A is grammatically incorrect and the only grammatically correct answer choices differ in meaning

We hope this helps.
All the best!
Experts' Global Team

MartyTargetTestPrep · Answer

Sometimes, to arrive at the credited answer to an SC question, you have to make a judgment call regarding which choice the writer of the question considered correct.

In this case, (A) is completely logical, and there's no reason not to choose it, whereas the meaning conveyed by the (C) version is a little suspect in that it seems unlikely that what astronomers would have discovered is that, in the past, there were 17 nearby stars that were orbited by planets.

So, while the meaning conveyed by (C) is conceivably logical under certain circumstances, we can get this question correct by going with (A).

woohoo921 · Answer

For Choice C, I see that an expert notes the following as to why this answer choice is incorrect "Again, this is INCORRECT because the use of past tense here doesn't convey the correct meaning. The discoveries were made in the past, but the planets and stars are still behaving the same way today!" How do we know that these specific stars are still around today though? This SC problem seems to require some sort of background knowledge or to make an inference.

ExpertsGlobal5 · Answer

Hello  woohoo921 ,

We hope this finds you well.

To answer your query, you are correct; this question does require a bit of contextual understanding to eliminate C.

However, to some extent this is considered acceptable on GMAT; for example, if a sentence applies the simple present tense to an action taken by Napoleon, we can reasonably be expected to assume that it is incorrect.

Similarly, a statement about a scientific fact or discovery can reasonably be assumed to be a statement of a universal fact, something best conveyed through the simple present tense.

We hope this helps.
All the best!
Experts' Global Team

GMATNinja · Answer

At best, the timeline in (C) is confusing. We have a past perfect verb ("had discovered") which points to a time before another moment in the past (1999). Then we get two additional simple past verbs ("were" and "were orbited"). Where do we put those two simple past verbs on the timeline? At 1999? Sometime before the past perfect verb? Did those stars/planets cease to exist well before 1999? Or sometime between 1999 and the present? The latter, while possible, seems unlikely: did all 17 of those stars suddenly vanish after 1999?. And if we go with the former, that means that the scientists discovered things that no longer exist -- also certainly possible, but seems a little fishy in this context. The reader has to choose between two suspicious (though feasible) options, and that makes the meaning in (C) unclear. In (A), however, the use of the simple present ("are") makes the meaning clear and unambiguous: the stars are still orbited by the planets, so the reader knows that both still exist. So (A) is definitely the clearer option, regardless of what you know about astronomy.

ArnauG · Answer

The correct answer is (A):

By 1999, astronomers had discovered 17 nearby stars that are orbited by planets.

This sentence uses the correct verb tense (past perfect) to describe an action that was completed before a specified time (1999). Option (B) is also grammatically correct, but it unnecessarily changes the word order and adds a prepositional phrase. Option (C) changes the meaning of the sentence by adding "that there were." Option (D) uses the present perfect tense, which implies a connection to the present, whereas the sentence is describing a past event. Option (E) changes the structure of the sentence and implies that the stars were discovered in 1999, which is not necessarily true.

paritoshmahajan · Answer

In OE, It is mentioned that in the second option, " had discovered 17 nearby stars with planets orbiting them that were", 'that' is not clear whether it refers to stars or planets. However, since that is a noun modifier, which is supposed to follow touch rule, isn't it clear that it refers to the planets.

Or is it because of the exception to the touch rule, where 'with planets' is a vital modifier and hence there is ambiguity b/w planets and stars?

daagh GMATNinja egmat Magoosh

Or is it because of the exception to the touch rule, where 'with planets' is a vital modifier and hence there is ambiguity b/w planets and stars?

daagh   GMATNinja   egmat   Magoosh

GMATNinja · Answer

It sounds like you've answered your own question!

The touch "rule" is more of a guideline than a rule, as discussed in  this post . In choice (B), you could indeed argue that the "that" modifies either "stars" or "planets".

(A) avoids that issue, making it a clearer and better option.

I hope that helps!

faaizmasood55 · Answer

Isnt "That" a singular pronoun? why are we using it for 17 nearby stars? I am a bit confused -  GMATNinja

GMATNinja · Answer

"That"  can  be used as a singular pronoun ("The economy of Chile is stronger than  that of  Argentina."), but it can also be used as part of a modifier, in which case it can modify both singular and plural nouns.

Check out this post  this post  for more.  This article  or  this video  might help a bit, too.

By 1999, astronomers had discovered 17 nearby stars that are orbited

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By 1999, astronomers had discovered 17 nearby stars that are orbited

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