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

Hello Everyone!

While we answered this one for you a while ago, let's go back and rework this using the EMPOWERgmat method! First, let's take a quick glance over the options and highlight any major differences we can find in orange:

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

After a quick glance over the options, we found 2 places we can focus on:

1. had discovered / have discovered (Verb Tense)
2. How each option ends (Modifiers / Verb Tense / Meaning)

Let's start with #1 on our list because it will eliminate 2-3 options right away. This is a pretty easy one because it has to do with verb tenses! If we look at the entire sentence for clues, we can figure out which verb tense we need:

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

Since all of the discoveries were started AND FINISHED in the past, it makes the most sense to use the past perfect tense! If we were talking about discoveries that were started in the past, but were still being made today, it would make sense to use present perfect tense. Let's see how our options stack up:

(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

We can easily eliminate options D & E because they use the present perfect instead of the past perfect verb tense.

Now that we have things narrowed down, let's tackle #2 on our list: how each option ends. We need to make sure that any modifiers we find work (hint: they'll start with the word "that"), and make sure any verbs we find make sense:

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

This is CORRECT! It makes more sense to say that the stars are currently orbited by planets. The planets were discovered orbiting stars in 1999, but it's safe to say they're still doing so today.

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

This is INCORRECT because the use of the past tense "were" doesn't work here. The planets are STILL the size of Jupiter - that didn't change after 1999. Since we're talking about a phenomenon that was discovered in the past, but still goes on today, it makes more sense to use present tense verbs here.

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

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!


There you have it - option A was the correct choice all along! If we focus on the either/or differences between options, it's easy to eliminate wrong ones quickly!


Don't study for the GMAT. Train for it.

Dear Friends,

Here is a detailed explanation to this question-

Meaning is crucial to solving this problem:
Understanding the intended meaning is key to solving this question; the intended meaning of this sentence is that by 1999, astronomers had discovered 17 nearby stars that are orbited by planets about the size of Jupiter.

Concepts tested here: Meaning + Tenses + Pronouns + Awkwardness/Redundancy

• Statements of universal fact are best conveyed through the simple present tense.
• Present participles ("verb+ing" – “orbiting” in this sentence) are used to modify nouns, refer to ongoing events in any time period, and (when preceded by a comma) express cause-effect relationships.
• The past perfect tense (marked by the use of helping verb "had") is used when a sentence contains two actions in the past; the helping verb "had" is used with the action in the "greater past".
• The present perfect tense (marked by the use of the helping verb “has/have”) is used to describe events that concluded in the past but continue to affect the present.

A: Correct. This answer choice uses the phrase "discovered 17 nearby stars", conveying the intended meaning - that astronomers discovered the 17 stars, themselves and that they are orbited by planets about the size of Jupiter. Further, Option A correctly uses the past perfect tense verb "had discovered" to refer to the earlier of two actions - the coming of the year 1999 and astronomers discovering the 17 nearby stars. Moreover, Option A correctly uses the simple present tense verb "are orbited" to refer to a statement of universal fact. Option A also avoids the error related to the use of the simple past tense, seen in Options B and C, as it uses the adjective phrase "planets about the size of Jupiter" rather than an active verb. Additionally, Option A clearly uses the pronoun "that" to refer to the noun "stars". Besides, Option A is free of any awkwardness or redundancy.

B: This answer choice incorrectly uses the present participle ("verb+ing" - "orbiting" in this sentence) to refer to a statement of universal fact; please remember, statements of universal fact are best conveyed through the simple present tense, and present participles ("verb+ing" – “orbiting” in this sentence) are used to modify nouns, refer to ongoing events in any time period, and (when preceded by a comma) express cause-effect relationships. Moreover, Option B incorrectly uses the simple past tense verb "were" to refer to a statement of universal fact; please remember, statements of universal fact are best conveyed through the simple present tense, and the simple past tense is used to refer to events that concluded in the past. Further, Option B suffers from pronoun ambiguity, as it is unclear whether "that" refers to "planets" or "stars".

C: This answer choice incorrectly uses the simple past tense verb "were" to refer to statements of universal fact; please remember, statements of universal fact are best conveyed through the simple present tense, and the simple past tense is used to refer to events that concluded in the past. Further, Option C uses the needlessly wordy phrase "that there were 17 nearby stars", leading to awkwardness and redundancy.

D: This answer choice incorrectly uses the present perfect tense verb "have discovered" to refer to the earlier of two actions - the coming of the year 1999 and astronomers discovered the 17 nearby stars; please remember, past perfect tense (marked by the use of helping verb "had") is used when a sentence contains two actions in the past; the helping verb "had" is used with the action in the "greater past", and the present perfect tense (marked by the use of the helping verb “has/have”) is used to describe events that concluded in the past but continue to affect the present. Further, Option D incorrectly uses the present participle ("verb+ing" - "orbiting" in this sentence) to refer to a statement of universal fact; please remember, statements of universal fact are best conveyed through the simple present tense, and present participles ("verb+ing" – “orbiting” in this sentence) are used to modify nouns, refer to ongoing events in any time period, and (when preceded by a comma) express cause-effect relationships. Additionally, Option D suffers from pronoun ambiguity, as it is unclear whether "that" refers to "planets" or "stars".

E: This answer choice alters the meaning of the sentence through the phrase "discovered that 17 nearby stars are orbited"; the construction of this phrase incorrectly implies that astronomers discovered the fact that 17 nearby, already known, stars are orbited by planets about the size of Jupiter; the intended meaning is that astronomers discovered the 17 stars, themselves and that they are orbited by planets about the size of Jupiter. Further, Option E incorrectly uses the present perfect tense verb "have discovered" to refer to the earlier of two actions - the coming of the year 1999 and astronomers discovered the 17 nearby stars; please remember, past perfect tense (marked by the use of helping verb "had") is used when a sentence contains two actions in the past; the helping verb "had" is used with the action in the "greater past", and the present perfect tense (marked by the use of the helping verb “has/have”) is used to describe events that concluded in the past but continue to affect the present.

Hence, A is the best answer choice.

All the best!
Experts' Global Team

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

OG Answer:
Opening with a past date (1999) describing the end point of a period of discovery, this sentence calls for a past perfect main verb to follow the subject astronomers. In order to economize on words and maximize clarity, the object of the main clause, stars, is modified by a passive relative clause that are orbited by planets followed by the adjective phrase about the size of Jupiter. This structure avoids an awkward and confusing clauses and prepositional phrases.

Hi,
I wonder whether there is a problem in "were about the size ..." in choice B? Does it indicate that the fact that those planets are about the size of Jupiter is no longer true, and that is the reason why this choice is incorrect.

In choice A, I did not choose it because of the word "are orbited". I though the sentence is about past event, then all verb should be in past tense.

Please help me with this problem. Thanks!

In B, there is an ambiguity. "that" could be referring to the stars or the planets. It's not a solid sentence.
Again, I would say answering based on tenses could be misleading here. There are safer clues you can use. But I think using simple present tense is okay since these planets probably have been orbiting these stars for billions of years and are going to do so for another billions of years.

Here, 1999 is implied past tense, so the discovery had taken place before 1999 so it takes Had#
eliminate D and E
B what does them refer to is it scientists or stars, this is reference error, so eliminate B
C were is wrong here because it is natural phenomena which is occurring even now so, we can eliminate C
Therefore answer is A

This is an excellent question that checks the usage of "That"!

I found this game on "That" - Check it out. It's awesome - made the concept very clear.
https://web.ku.edu/~edit/that.html

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.

Hello GMATNinja,

Can you help to review whether below analysis is correct?

In option B, we have a subtle meaning shift. By 1999, astronomers had discovered 17 nearby stars with planets. Can we say that astronomers discovered stars with planets is different from the original meaning that astronomers discovered stars?. Also, antecedent of them in choice B is ambiguous.

Similarly, C has a meaning shift - “By 1999, astronomers had discovered that there were 17 nearby stars”.

Since we have unambiguous meaning conveyed in A, we should retain the same.

Hello warriorguy,

I would be glad to help you with your query.


The meaning change in Choice B that you have mentioned in your post does not really stand.

The thing is whenever we read a sentence, we try to understand the meaning conveyed by it in its entirety. Hence, when we read Choice B, we understand that the sentence intends to say that the scientists had discovered 17 stars and planets orbited them.

The error with Choice B is that it suggests that the planets orbited the stars. They do not do so anymore. This is so because the main verb in Choice B is in past tense. Hence, the verb-ing modifier orbiting adopts the tense of the main verb and thus expresses illogical meaning. However, the correct answer choice A makes it absolutely clear that the planets still orbit these stars.

Choice C too repeats this meaning error. Choice C says that that the 17 stars discovered by the scientists existed in he past, and the planets orbited them in the past. Per the original sentence, the stars do exist in the present because some planets do orbit them.


Hope this helps.
Thanks.
Shraddha

The alleged ambiguity about 'them' may not sustain logically. The contenders, if at all any, are 1. astronomers, 2. planets, and 3. stars. Obviously, planets orbiting astronomers is too silly. Planets orbiting planets is also equally weird. Therefore, the logical and befitting referent for 'them' is only stars.

Hello Experts,
Can you please elaborate on the exact usage of 'that' here and what does it refer back to ?

Take another look at the OA: "By 1999, astronomers had discovered 17 nearby stars that are orbited by planets about the size of Jupiter." While it isn't mandatory for relative pronouns such as "that" to touch what they modify, the closest noun is certainly the first place you'd look. Here "that" is closest to "stars," and it makes perfect sense that the stars are "orbited by planets."

For a deeper look into the various uses of "that," check out this article or this video.

I hope that helps!

I would also like to point out one more thing about "that" with some examples -

1. I hate pizzas that have pineapple toppings.
Here "that" is necessary as it acts as a subject here.

2. I love the pizzas that GMATNinja cooks.
Here we see that "GMATNinja" is already the subject, so "that" is not necessary.

GMATNinja please correct me if i am wrong. Grammatically that is! Not with the pizza part.

Usage of "BY" vs "AT"-

I will just tweak the sentence a little for better understanding.

By the end of 1999, astronomers had discovered XYZ.

Here we see a sequence of events. First we see that the discovery happened and then 1999 ended.
What was the earlier part or first event? The astronomers discovered XYZ.
What was the later part or next event? 1999 ended.

So for the EARLIER part we use PAST PERFECT TENSE.


Now what if we had "AT" in the sentence?

At the end of 1999, astronomers discovered XYZ.

Here we have no sequence of events. The sentence says it is happening at a particular time by using "AT".
So we use SIMPLE PAST TENSE.

Hope it helps.

Grammatically, you're absolutely right. As for your feelings about pizza... actually, I'm not great at cooking pizza. I somehow figured out how to make really great polenta pizza, but "regular" pizza isn't my strength -- with or without pineapple. I make a killer lasagna, though.

But have you ever tried pizza with pineapple and bacon? Or at least Canadian bacon? It's not bad! And if you're ever in Brazil, try some of the fruit pizzas. I think Brazilians might have the most creative pizza topping combos on the planet -- banana curry pizza, anybody?

For this question. I am still confuse with answer option C. how its changing the meaning.