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GMAT Club Olympics 2025 (Day 9): Most known exoplanets lie too far 10 Jul 2025, 08:00
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Most known exoplanets lie too far from Earth to be observed directly and must instead be identified using indirect detection methods, such as measuring starlight distortions or subtle gravitational wobbles. However, these methods can generate reliable signal data only if the planet’s host star emits light in stable and consistent patterns over time. Therefore, few exoplanets are likely to produce detectable signals that can be consistently detected unless they are close enough to Earth to be observed directly.

Which of the following is an assumption required by the argument?

A. Indirect detection methods are less reliable than direct observation when gathering data about planetary atmospheres.
B. There are no alternative methods of detecting reliable signal data from exoplanets other than through shifts in starlight distortions or gravitational wobbles
C. Reliable interpretation of signal-related data depends more on the characteristics of the host star than on the exoplanet itself.
D. Exoplanets orbiting stars with consistent emission patterns are less common than those orbiting stars with inconsistent emissions.
E. Some exoplanets orbit stars with stable emissions but still fail to produce reliably detectable signals.


 


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GMAT Club Olympics 2025 (Day 9): Most known exoplanets lie too far 10 Jul 2025, 08:30
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Bunuel
Most known exoplanets lie too far from Earth to be observed directly and must instead be identified using indirect detection methods, such as measuring starlight distortions or subtle gravitational wobbles. However, these methods can generate reliable signal data only if the planet’s host star emits light in stable and consistent patterns over time. Therefore, few exoplanets are likely to produce detectable signals that can be consistently detected unless they are close enough to Earth to be observed directly.

The conclusion above follows logically if which of the following is assumed?

A. Indirect detection methods are less reliable than direct observation when gathering data about planetary atmospheres.
B. There are no alternative methods of detecting reliable signal data from exoplanets other than through shifts in starlight distortions or gravitational wobbles
C. Reliable interpretation of signal-related data depends more on the characteristics of the host star than on the exoplanet itself.
D. Exoplanets orbiting stars with consistent emission patterns are less common than those orbiting stars with inconsistent emissions.
E. Some exoplanets orbit stars with stable emissions but still fail to produce reliably detectable signals.
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­

GMAT Club Official Explanation:



Let’s break this argument down statistically for better clarity.

Quote:
Most known exoplanets lie too far from Earth to be observed directly and must instead be identified using indirect detection methods, such as measuring starlight distortions or subtle gravitational wobbles.
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Let’s say out of 100 total exoplanets, 10 are close enough to Earth to be observed directly. The remaining 90 are too far and require indirect methods like those mentioned above.

Quote:
However, these methods can generate reliable signal data only if the planet’s host star emits light in stable and consistent patterns over time.
Show more

So now we know that even for indirect methods to work, the host star must have stable emissions.

Quote:
Therefore, few exoplanets are likely to produce communication signals that can be consistently detected unless they are close enough to Earth to be observed directly.
Show more

Whoa, that’s a leap! It’s saying unless an exoplanet is one of those 10 close ones, only a few of the remaining 90 will reliably produce communication signals.

Let’s say out of the 90 faraway exoplanets, only 20 orbit stars with stable emissions and therefore can be reliably detected. The remaining 70 orbit unstable stars, making detection inconsistent.

So to recap:

  • 10 exoplanets (near) -> observable directly
  • 90 exoplanets (far) -> need indirect methods - Out of these 90: 20 -> stable stars -> consistent signals & 70 -> unstable stars -> inconsistent signals

This whole conclusion only works if that distribution holds true and we’re supposed to find which assumption makes the argument logically follow.

Let's go through the options now -

A. Indirect detection methods are less reliable than direct observation when gathering data about planetary atmospheres.

– Do we know anything about a comparison between the results of direct and indirect methods? I don't think so. What we can reliably say is that for planets which are far away, we will need to use indirect methods. So this option is incorrect.

B. There are no alternative methods of detecting reliable signal data from exoplanets other than through shifts in starlight distortions or subtle gravitational wobbles

– Good trap. First trap is that it's talking about all exoplanets and not only the ones that are far away from Earth, whereas the near ones use direct methods for measurement.

Ideally you should have already eliminated this choice by now, if not,
Second, we definitely need to use indirect methods to detect exoplanets that are far from Earth, and a couple of techniques used are starlight distortions and gravitational wobbles.

But do we know there's no other indirect method apart from these two that can be used for this measurement?

The argument only discusses a few examples using the phrase "such as", so it would be a strong hypothesis to rule out any others as it's not explicitly stated in the argument and hence, this is not an implied assumption. And if there does exist other indirect methods to detect reliable signal data, does the conclusion break? Don't think so, as the conclusion was made for all indirect methods not the only ones mentioned in the argument.

C. Reliable interpretation of signal-related data depends more on the characteristics of the host star than on the exoplanet itself.

– This might be true, but it’s not implied in any way by the given argument.

It could well be the case that the characteristics of the host star are one attribute required for communication, but other attributes of the exoplanet like its structure and atmosphere could be equally important for reliable communication.

D. Exoplanets orbiting stars with consistent emission patterns are less common than those orbiting stars with inconsistent emissions.

– Right on point! As we noted from our earlier statistics, exoplanets with inconsistent emissions i.e., 70 out of 100 are far greater than the other ones. So this is clearly an assumption of the argument.

If we negate this, say the ones with consistent emissions are more common, then exoplanets with consistent host stars would likely be in the majority, and the conclusion that "few exoplanets are likely to produce communication signals that can be consistently detected" would completely fall apart.

E. Some exoplanets orbit stars with stable emissions but still fail to produce reliably detectable signals.

– Sure, this might be true, but the argument doesn’t need it. Even if 5 out of the 20 stable ones failed to produce signals, there would still be few left, and the conclusion would still stand. This isn’t something the argument depends on but it’s just extra information.

Answer D
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GMAT Club Olympics 2025 (Day 9): Most known exoplanets lie too far 10 Jul 2025, 08:11
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The conclusion is only a few explonates are likely to produce detectable signals, unless they are near.

Option B states that there are no other alternatives for detecting exoplanets other than starlight distortions or gravitational wobbles, indicating that only a few exoplanets can be detected. If there were other ways to detect exoplanets, then many more could be found.
So option B is the best fit.
Bunuel
Most known exoplanets lie too far from Earth to be observed directly and must instead be identified using indirect detection methods, such as measuring starlight distortions or subtle gravitational wobbles. However, these methods can generate reliable signal data only if the planet’s host star emits light in stable and consistent patterns over time. Therefore, few exoplanets are likely to produce detectable signals that can be consistently detected unless they are close enough to Earth to be observed directly.

The conclusion above follows logically if which of the following is assumed?

A. Indirect detection methods are less reliable than direct observation when gathering data about planetary atmospheres.
B. There are no alternative methods of detecting reliable signal data from exoplanets other than through shifts in starlight distortions or gravitational wobbles
C. Reliable interpretation of signal-related data depends more on the characteristics of the host star than on the exoplanet itself.
D. Exoplanets orbiting stars with consistent emission patterns are less common than those orbiting stars with inconsistent emissions.
E. Some exoplanets orbit stars with stable emissions but still fail to produce reliably detectable signals.


 


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GMAT Club Olympics 2025 (Day 9): Most known exoplanets lie too far 10 Jul 2025, 08:58
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Premise :
Most known exoplanets lie too far from Earth to be observed directly and must instead be identified using indirect detection methods, such as measuring starlight distortions or subtle gravitational wobbles


IC : However, these methods can generate reliable signal data only if the planet’s host star emits light in stable and consistent patterns over time
Conclusion : Therefore, few exoplanets are likely to produce detectable signals that can be consistently detected unless they are close enough to Earth to be observed directly.

Assumption based CR , use negation technique to weaken conclusion

A. Indirect detection methods are more reliable than direct observation when gathering data about planetary atmospheres. does not weaken the conclusion

B. There are alternative methods of detecting reliable signal data from exoplanets other than through shifts in starlight distortions or gravitational wobbles
the option weakens the conclusion as it gives reason of having alternative methods to detect reliable signal....

C. Reliable interpretation of signal-related data does not depends more on the characteristics of the host star than on the exoplanet itself.
this is close option , but not on the lines of conclusion

D. Exoplanets orbiting stars with consistent emission patterns are more common than those orbiting stars with inconsistent emissions.
irrelevant to conclusion

E. all exoplanets orbit stars with stable emissions but still fail to produce reliably detectable signals.
does not weaken the conclusion

OPTION B is correct

Bunuel
Most known exoplanets lie too far from Earth to be observed directly and must instead be identified using indirect detection methods, such as measuring starlight distortions or subtle gravitational wobbles. However, these methods can generate reliable signal data only if the planet’s host star emits light in stable and consistent patterns over time. Therefore, few exoplanets are likely to produce detectable signals that can be consistently detected unless they are close enough to Earth to be observed directly.

The conclusion above follows logically if which of the following is assumed?

A. Indirect detection methods are less reliable than direct observation when gathering data about planetary atmospheres.
B. There are no alternative methods of detecting reliable signal data from exoplanets other than through shifts in starlight distortions or gravitational wobbles
C. Reliable interpretation of signal-related data depends more on the characteristics of the host star than on the exoplanet itself.
D. Exoplanets orbiting stars with consistent emission patterns are less common than those orbiting stars with inconsistent emissions.
E. Some exoplanets orbit stars with stable emissions but still fail to produce reliably detectable signals.


 


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GMAT Club Olympics 2025 (Day 9): Most known exoplanets lie too far 10 Jul 2025, 08:59
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Therefore, few exoplanets are likely to produce detectable signals that can be consistently detected unless they are close enough to Earth to be observed directly.

Option D says :
Exoplanets orbiting stars with consistent emission patterns are less common than those orbiting stars with inconsistent emissions.

This is correct since the conclusion states “few exoplanets are likely to produce detectable signals “. The passage states that detectable signals require consistent emission patterns. Thus this option is the Assumption that bridges the gap in the passage and conclusion.

Answer is D
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GMAT Club Olympics 2025 (Day 9): Most known exoplanets lie too far 10 Jul 2025, 09:03
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The user is asking for an assumption that makes the conclusion logically follow from the premise. Let's break down the argument:

Premise 1: Most known exoplanets are too far for direct observation and rely on indirect methods (starlight distortions, gravitational wobbles).

Premise 2: Indirect methods generate reliable data only if the host star emits light in stable and consistent patterns.

Conclusion: Few exoplanets are likely to produce consistently detectable signals unless they are close enough to Earth for direct observation.

The gap is between the need for stable stellar emissions for indirect methods and the conclusion that few exoplanets will produce detectable signals unless directly observed. The conclusion implies that if a planet isn't directly observed, it's unlikely to produce detectable signals.

Let's examine the options:

A. Indirect detection methods are less reliable than direct observation when gathering data about planetary atmospheres. This is about reliability for specific data (atmospheres) and doesn't bridge the gap concerning the detectability of the exoplanet itself.

B. There are no alternative methods of detecting reliable signal data from exoplanets other than through shifts in starlight distortions or gravitational wobbles. This option directly addresses the "unless they are close enough to Earth to be observed directly" part of the conclusion. If these are the only indirect methods, and they rely on stable stellar emissions, then if those emissions aren't stable, or if direct observation isn't possible, then there are no other reliable ways to detect them. This aligns with the argument that if indirect methods fail (due to unstable stars), and direct observation isn't possible, then detection is unlikely.

C. Reliable interpretation of signal-related data depends more on the characteristics of the host star than on the exoplanet itself. While the premise states that host star characteristics are important for indirect methods, this option doesn't explain why few exoplanets would produce detectable signals. It just reiterates the importance of the star.

D. Exoplanets orbiting stars with consistent emission patterns are less common than those orbiting stars with inconsistent emissions. If this were true, it would strengthen the conclusion that few exoplanets produce detectable signals. However, it's not strictly an assumption required for the logic to hold. The argument already states that if stars aren't stable, indirect methods fail. This option suggests why many stars might not be stable, but the core logical jump is about the reliance on those specific methods.

E. Some exoplanets orbit stars with stable emissions but still fail to produce reliably detectable signals. This would suggest that even with stable stars, detection isn't guaranteed, which weakens the idea that stable stars allow for reliable detection, rather than strengthening the overall conclusion.

The key to the logical leap is that if direct observation isn't possible, we must rely on the described indirect methods. If those methods are the only ones for reliable signals from distant planets, and they have the stellar stability prerequisite, then the conclusion follows.

Therefore, option B is the necessary assumption.

The final answer is B
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GMAT Club Olympics 2025 (Day 9): Most known exoplanets lie too far 10 Jul 2025, 09:04
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The paragraph states about detecting of reliable signal data from exoplanets by using indirect methods as they lie too far from the earth to be observed directly.
Coming to the question,

A. Indirect detections methods are reliable to generate reliable data- this option doent support the conclusion
B. There are alternative methods of detecting reliable signal data ,this option doesn’t
C. Yes, reliable interpretation of signal data depends more on the characteristics of the host star
D. Exoplanets orbiting stars with inconsistent emissions will not generate reliable data-this doesn’t support the conclusion
E. Exoplanets with stable emissions not producing reliable signals is not mentioned in the paragraph.

Hence , C is the answer.
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GMAT Club Olympics 2025 (Day 9): Most known exoplanets lie too far 10 Jul 2025, 09:09
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The Zoologist's Argument:
  1. Premise 1: Most faraway planets can't be seen directly.
  2. Premise 2: So, we find them using "indirect methods" (like looking at how their star's light wiggles, or how the star itself wobbles because of the planet's gravity). Let's call these "Wobble & Wiggle methods" for the ease of understanding
  3. Premise 3: Crucial Rule! These "Wobble & Wiggle methods" only give data if the star is super steady and consistent in its light and movement. If the star is erratic, the data from these methods is junk.
  4. Conclusion: Because of all this, it's very unlikely we'll consistently find many faraway planets, unless they're close enough to see directly.
Now, let's Prethink
The zoologist is saying, "Hey, if a planet is far away, we probably won't find it consistently." Why? Because our main tools ("Wobble & Wiggle methods") need a steady star.
But wait! What if there's another tool?
Imagine I tell you: "You can only dig a hole with a shovel. Shovels only work if the ground is soft. Therefore, you probably can't dig a hole if the ground is hard."
You might think, "Okay, that makes sense for shovels. But what if I have a pickaxe? Or a drill? Those could dig a hole even if the ground is hard!"
This is the "gap" in the zoologist's argument about the exoplanets.
The zoologist says "Wobble & Wiggle methods" are the ones used for faraway planets, and they need steady stars. Then they jump to the conclusion: "So, if the star isn't steady, you're out of luck for consistent detection."
But what if there are other ways to detect these faraway planets reliably? Ways that don't need a steady star? If those existed, the conclusion wouldn't necessarily follow.
This is where Option B comes in:
B. There are no alternative methods of detecting reliable signal data from exoplanets other than through shifts in starlight distortions or gravitational wobbles.
Let's put this option into the argument as an unstated rule:
  1. Premise 1: Most faraway planets can't be seen directly.
  2. Premise 2: So, we find them using "Wobble & Wiggle methods."
  3. Premise 3: Crucial Rule! "Wobble & Wiggle methods" only work well (give "reliable data") IF the star is super steady. (Meaning: if the star is not steady, these methods don't give reliable data).
  4. Assumed Rule (Option B): AND, by the way, "Wobble & Wiggle methods" are the ONLY ways to get reliable data from faraway planets. There are no other tricks or tools.
Now, let's see if the conclusion makes sense:
Okay, so if a planet is far away:
  • We have to use "Wobble & Wiggle methods" (from Premise 2).
  • These "Wobble & Wiggle methods" only work with a steady star (from Premise 3).
  • And there are no other methods (from Option B).
Therefore, if the star isn't steady, we simply have no way to get reliable data to consistently detect that faraway planet. This means "few" of them will be consistently detectable, as the argument concludes.
Option B is like saying, "Yes, the shovel is the only tool you have." If the shovel needs soft ground, and the ground is hard, then you really can't dig that hole. Without option B, I could always say, "But what about my pickaxe?"
So, Option B is the hidden assumption that makes the conclusion logically watertight by eliminating any other potential ways to detect those planets that don't depend on the star's stability.






Bunuel
Most known exoplanets lie too far from Earth to be observed directly and must instead be identified using indirect detection methods, such as measuring starlight distortions or subtle gravitational wobbles. However, these methods can generate reliable signal data only if the planet’s host star emits light in stable and consistent patterns over time. Therefore, few exoplanets are likely to produce detectable signals that can be consistently detected unless they are close enough to Earth to be observed directly.

The conclusion above follows logically if which of the following is assumed?

A. Indirect detection methods are less reliable than direct observation when gathering data about planetary atmospheres.
B. There are no alternative methods of detecting reliable signal data from exoplanets other than through shifts in starlight distortions or gravitational wobbles
C. Reliable interpretation of signal-related data depends more on the characteristics of the host star than on the exoplanet itself.
D. Exoplanets orbiting stars with consistent emission patterns are less common than those orbiting stars with inconsistent emissions.
E. Some exoplanets orbit stars with stable emissions but still fail to produce reliably detectable signals.


 


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Let's look for the assumption:

A. Indirect detection methods are less reliable than direct observation when gathering data about planetary atmospheres.
  • This doesn't affect the conclusion of the argument. Eliminate.
B. There are no alternative methods of detecting reliable signal data from exoplanets other than through shifts in starlight distortions or gravitational wobbles
  • Let's say this is true, is it necessary for us to know this information to say that there are only a few exoplanets that are likely to produce detectable signals? No. Eliminate.
C. Reliable interpretation of signal-related data depends more on the characteristics of the host star than on the exoplanet itself.
  • Distortion. We are trying to find an assumption that is based on the methods that are said to generate "reliable" signal data, "reliable interpretation" is just a distortion of the premise given. Eliminate
D. Exoplanets orbiting stars with consistent emission patterns are less common than those orbiting stars with inconsistent emissions.
  • This says that the combination of exoplanets+stars with consistent emission if less common than the combination of exoplanets+stars with inconsistent emission. This is just another way of saying that there a fewer exoplanets that will be able to produce detectable signals since fewer of them have stars that consistently emit light. This strengthens the conclusion and makes the argument more sound. Keep
E. Some exoplanets orbit stars with stable emissions but still fail to produce reliably detectable signals.
  • "Some" narrows down the scope. Even if this info is true, this doesn't help us arrive at our conclusion. Eliminate

D seems to be the best choice.
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GMAT Club Olympics 2025 (Day 9): Most known exoplanets lie too far 10 Jul 2025, 09:17
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The argument’s conclusion rests on the idea that only a small fraction of exoplanets orbit stars with the steady, unvarying light patterns required for reliable indirect detection methods, so unless a planet is close enough to be imaged directly, its host star’s variability will swamp any detectable signal. This is precisely what choice D asserts.
The other options fail to secure the leap to the conclusion. A compares direct and indirect methods but says nothing about the rarity of stable stars, B rules out exotic detection techniques but doesn’t explain why indirect signals are seldom reliable, C emphasizes the host star’s role without stating that stably emitting stars are uncommon, and E concedes that some stable‐emission systems still yield no signal, which actually undermines the argument by suggesting variability isn’t the sole barrier.

Bunuel
Most known exoplanets lie too far from Earth to be observed directly and must instead be identified using indirect detection methods, such as measuring starlight distortions or subtle gravitational wobbles. However, these methods can generate reliable signal data only if the planet’s host star emits light in stable and consistent patterns over time. Therefore, few exoplanets are likely to produce detectable signals that can be consistently detected unless they are close enough to Earth to be observed directly.

The conclusion above follows logically if which of the following is assumed?

A. Indirect detection methods are less reliable than direct observation when gathering data about planetary atmospheres.
B. There are no alternative methods of detecting reliable signal data from exoplanets other than through shifts in starlight distortions or gravitational wobbles
C. Reliable interpretation of signal-related data depends more on the characteristics of the host star than on the exoplanet itself.
D. Exoplanets orbiting stars with consistent emission patterns are less common than those orbiting stars with inconsistent emissions.
E. Some exoplanets orbit stars with stable emissions but still fail to produce reliably detectable signals.


 


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GMAT Club Olympics 2025 (Day 9): Most known exoplanets lie too far 10 Jul 2025, 09:18
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Premise 1: Most exoplanets are too far away for direct observation and require indirect detection methods.
Premise 2: Indirect detection methods work only if the host star has stable and consistent light patterns.
Conclusion: Few exoplanets are likely to produce detectable signals unless they're close enough for direct observation.
There's a gap between premise 2 and the conclusion. The argument assumes something about the stability of stars light patterns. For the conclusion to follow logically, we need to assume that most stars don't have the stable and consistent light patterns required for indirect detection methods to work effectively.
Let's evaluate each option:
A. This compares reliability of methods for planetary atmospheres, but the argument is about detecting exoplanets themselves, not specfially their atmospheres. Not the assumption.
B. Even if alternative methods existed, the conclusion could still be valid if those methods also required close proximity. Not the assumption.
C. This is irrelevant to the conclusion about the quantity of detectable exoplanets. Not the assumption.
D. This states that exoplanets orbiting stars with consistent emission patters are less common than those orbiting stars with inconsistent emissions. This is exactly what we need to bridge the gap! If most stars have inconsistent emissions, then indirect methods won't work for most exoplanets, supporting the conclusion that few exoplanets produce detectable signals unless they're close enough for direct observation.
E. This actually weakens the argument by suggesting that even with stable emissions, detection might fail. Not the assumption.
The correct answer is D.
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GMAT Club Olympics 2025 (Day 9): Most known exoplanets lie too far 10 Jul 2025, 09:33
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The argument concludes that few exoplanets produce consistently detectable signals unless they are close enough to be observed directly because indirect methods require their host stars to emit stable, consistent light. For this conclusion to hold, it must be assumed that the reliability of signal detection depends primarily on the stability of the host star’s emissions rather than on any characteristics of the exoplanet itself. Option C directly states this assumption, making it essential for the conclusion. Option A compares the reliability of indirect versus direct methods for studying atmospheres, which is irrelevant to the detection issue. Option B claims no alternative detection methods exist beyond those mentioned, but the argument focuses on the role of star stability, not the exclusivity of methods. Option D suggests that stars with stable emissions are less common, which affects frequency but not the logic of detectability. Option E states that some exoplanets orbit stable stars yet fail detection, which contradicts the premise that stability enables reliable signals. Thus, only option C provides the necessary assumption for the argument’s conclusion.
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GMAT Club Olympics 2025 (Day 9): Most known exoplanets lie too far 10 Jul 2025, 09:41
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Bunuel
Most known exoplanets lie too far from Earth to be observed directly and must instead be identified using indirect detection methods, such as measuring starlight distortions or subtle gravitational wobbles. However, these methods can generate reliable signal data only if the planet’s host star emits light in stable and consistent patterns over time. Therefore, few exoplanets are likely to produce detectable signals that can be consistently detected unless they are close enough to Earth to be observed directly.

The conclusion above follows logically if which of the following is assumed?

A. Indirect detection methods are less reliable than direct observation when gathering data about planetary atmospheres.
B. There are no alternative methods of detecting reliable signal data from exoplanets other than through shifts in starlight distortions or gravitational wobbles
C. Reliable interpretation of signal-related data depends more on the characteristics of the host star than on the exoplanet itself.
D. Exoplanets orbiting stars with consistent emission patterns are less common than those orbiting stars with inconsistent emissions.
E. Some exoplanets orbit stars with stable emissions but still fail to produce reliably detectable signals.


 


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A. Trap, Challenges premises. So Not correct.
B. Trap, again Challenges premises. So Not correct.
C. Trap, as when you negate it the conclusion still stands that there are few exoplanets that can be detectable.
D. Correct, because there is a unexplained connection between few exoplanets detectable and the method used to detect them.
E. This is a more of a strengthening option by still not mentioning about the connection between premises and conclusion.
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GMAT Club Olympics 2025 (Day 9): Most known exoplanets lie too far 10 Jul 2025, 09:44
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Most known exoplanets lie too far from Earth to be observed directly and must instead be identified using indirect detection methods, such as measuring starlight distortions or subtle gravitational wobbles. However, these methods can generate reliable signal data only if the planet’s host star emits light in stable and consistent patterns over time. Therefore, few exoplanets are likely to produce detectable signals that can be consistently detected unless they are close enough to Earth to be observed directly......

The conclusion above follows logically if which of the following is assumed?

A. Indirect detection methods are less reliable than direct observation when gathering data about planetary atmospheres...... it compares types of data collection,.........No

B. There are no alternative methods of detecting reliable signal data from exoplanets other than through shifts in starlight distortions or gravitational wobbles.......... This assumption fills the gap in reasoning, If there were other detection methods, then the conclusion (few exoplanets can be detected unless they are close) wouldn’t hold..........Possible answer

C. Reliable interpretation of signal-related data depends more on the characteristics of the host star than on the exoplanet itself............. The conclusion is about whether detection is possible, not who matters mor...........No
D. Exoplanets orbiting stars with consistent emission patterns are less common than those orbiting stars with inconsistent emissions.......... support the idea that most stars aren’t stable, but this isn’t alone enough.......Maybe
E. Some exoplanets orbit stars with stable emissions but still fail to produce reliably detectable signals.........This weakens the arguement.......No

B
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GMAT Club Olympics 2025 (Day 9): Most known exoplanets lie too far 10 Jul 2025, 09:48
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Conclusion: Therefore, few exoplanets are likely to produce detectable signals that can be consistently detected unless they are close enough to Earth to be observed directly.
The conclusion jumps to far from the previous premises. It assume that few exoplanets emits light in stable and consistent patterns over time

The conclusion above follows logically if which of the following is assumed?

A. Indirect detection methods are less reliable than direct observation when gathering data about planetary atmospheres.
irrelevant, not the right answer

B. There are no alternative methods of detecting reliable signal data from exoplanets other than through shifts in starlight distortions or gravitational wobbles
Out of scope

C. Reliable interpretation of signal-related data depends more on the characteristics of the host star than on the exoplanet itself.
not assumptiom

D. Exoplanets orbiting stars with consistent emission patterns are less common than those orbiting stars with inconsistent emissions.
Yes, the right answer.

E. Some exoplanets orbit stars with stable emissions but still fail to produce reliably detectable signals.
New info but not the assumption
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GMAT Club Olympics 2025 (Day 9): Most known exoplanets lie too far 10 Jul 2025, 09:53
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A. Indirect detection methods are less reliable than direct observation for planetary atmospheres.
Off-topic — atmosphere is not the issue here.

B. There are no alternative methods of detecting reliable signal data from exoplanets other than through shifts in starlight distortions or gravitational wobbles.
Yes! This assumption is necessary.
If other methods existed, the conclusion (that only nearby ones are detectable) wouldn't hold. ---> Answer

C. Reliable interpretation of signal-related data depends more on the characteristics of the host star than on the exoplanet itself.
May be true, but doesn't connect to the conclusion.

D. Exoplanets orbiting stars with consistent emission patterns are less common than those orbiting inconsistent stars.
Even if true, this is evidence, not a required assumption.

E. Some exoplanets orbit stars with stable emissions but still fail to produce reliably detectable signals.
This weakens the argument by showing that even stable stars don’t guarantee detection.
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GMAT Club Olympics 2025 (Day 9): Most known exoplanets lie too far 10 Jul 2025, 09:54
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Bunuel
Most known exoplanets lie too far from Earth to be observed directly and must instead be identified using indirect detection methods, such as measuring starlight distortions or subtle gravitational wobbles. However, these methods can generate reliable signal data only if the planet’s host star emits light in stable and consistent patterns over time. Therefore, few exoplanets are likely to produce detectable signals that can be consistently detected unless they are close enough to Earth to be observed directly.

The conclusion above follows logically if which of the following is assumed?

A. Indirect detection methods are less reliable than direct observation when gathering data about planetary atmospheres.
B. There are no alternative methods of detecting reliable signal data from exoplanets other than through shifts in starlight distortions or gravitational wobbles
C. Reliable interpretation of signal-related data depends more on the characteristics of the host star than on the exoplanet itself.
D. Exoplanets orbiting stars with consistent emission patterns are less common than those orbiting stars with inconsistent emissions.
E. Some exoplanets orbit stars with stable emissions but still fail to produce reliably detectable signals.


 


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it option B because we assume the starlight distortion for detection
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GMAT Club Olympics 2025 (Day 9): Most known exoplanets lie too far 10 Jul 2025, 09:58
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Conclusion is few exoplanets are likely to produce detectable signals that can be consistently detected unless they are close enough to Earth to be observed directly.


A. Indirect detection methods are less reliable than direct observation when gathering data about planetary atmospheres.: this comparison between indirect & direct method is unwarranted

B. There are no alternative methods of detecting reliable signal data from exoplanets other than through shifts in starlight distortions or gravitational wobbles. Negation of this, There are alternative methods of detecting reliable signal data from exoplanets other than through shifts in starlight distortions or gravitational wobbles, If alternative indirect methods are available which are reliable, then it won't be a requirement for exoplanets to be close enough to Earth to be observed directly. Negation of this statement breaks the conclusion, hence CORRECT

C. Reliable interpretation of signal-related data depends more on the characteristics of the host star than on the exoplanet itself. We aren't concerned with Reliable interpretation, we are concerned with receiving reliable signal data

D. Exoplanets orbiting stars with consistent emission patterns are less common than those orbiting stars with inconsistent emissions. Negating this, Exoplanets orbiting stars with consistent emission patterns are not less common than those orbiting stars with inconsistent emissions. Negation of this doesn't break the conclusion, rather support it, hence eliminate

E. Some exoplanets orbit stars with stable emissions but still fail to produce reliably detectable signals. Go against the fact in the arguement that the indirect methods can generate reliable signal data only if the planet’s host star emits light in stable and consistent patterns over time.

Ans B
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GMAT Club Olympics 2025 (Day 9): Most known exoplanets lie too far 10 Jul 2025, 10:04
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Most known exoplanets lie too far from Earth to be observed directly and
must instead be identified using indirect detection methods, such as measuring starlight distortions or subtle gravitational wobbles.
However, these methods can generate reliable signal data only if the planet’s host star emits light in stable and consistent patterns over time. Therefore, few exoplanets are likely to produce detectable signals that can be consistently detected unless they are close enough to Earth to be observed directly.

Assumption: only few exoplanets which are too far from earth emit light in stable and consistent patterns over time

A. Indirect detection methods are less reliable than direct observation when gathering data about planetary atmospheres. reliability of detection method not a consideration here
B. There are no alternative methods of detecting reliable signal data from exoplanets other than through shifts in starlight distortions or gravitational wobbles We don't know that, may be there's something else to help find those near the Earth, i.e. direct methods
C. Reliable interpretation of signal-related data depends more on the characteristics of the host star than on the exoplanet itself. This is not a must be true, again reliable interpretation is not a concern
D. Exoplanets orbiting stars with consistent emission patterns are less common than those orbiting stars with inconsistent emissions. This is aligned with the prethinking, links why few exoplanets are likely to produce detectable signals
E. Some exoplanets orbit stars with stable emissions but still fail to produce reliably detectable signals. reliability of detection not a consideration here
Bunuel
Most known exoplanets lie too far from Earth to be observed directly and must instead be identified using indirect detection methods, such as measuring starlight distortions or subtle gravitational wobbles. However, these methods can generate reliable signal data only if the planet’s host star emits light in stable and consistent patterns over time. Therefore, few exoplanets are likely to produce detectable signals that can be consistently detected unless they are close enough to Earth to be observed directly.

The conclusion above follows logically if which of the following is assumed?

A. Indirect detection methods are less reliable than direct observation when gathering data about planetary atmospheres.
B. There are no alternative methods of detecting reliable signal data from exoplanets other than through shifts in starlight distortions or gravitational wobbles
C. Reliable interpretation of signal-related data depends more on the characteristics of the host star than on the exoplanet itself.
D. Exoplanets orbiting stars with consistent emission patterns are less common than those orbiting stars with inconsistent emissions.
E. Some exoplanets orbit stars with stable emissions but still fail to produce reliably detectable signals.


 


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GMAT Club Olympics 2025 (Day 9): Most known exoplanets lie too far 10 Jul 2025, 10:10
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A. Indirect detection methods are less reliable than direct observation when gathering data about planetary atmospheres.
This is about reliability for specific data (atmospheres) and a comparison between methods, not about the overall detectability of a signal which is the focus of the conclusion. It doesn't bridge the gap.

B. There are no alternative methods of detecting reliable signal data from exoplanets other than through shifts in starlight distortions or gravitational wobbles.
If these two indirect methods (starlight distortions and gravitational wobbles) are the only ways to get reliable signal data indirectly, and they both rely on stable host stars, then the conclusion that few exoplanets will produce detectable signals unless observed directly makes sense. The argument has established that these indirect methods are the primary ones for distant planets and that they have a specific requirement (stable stars). If there are no other indirect methods, then the stability of the host star becomes a critical bottleneck for detection.

C. Reliable interpretation of signal-related data depends more on the characteristics of the host star than on the exoplanet itself.
While the passage states that reliable data depends on the host star's patterns, saying it depends more on the host star than the exoplanet is a comparative statement that isn't necessary for the conclusion to follow. The argument only needs the host star's stability to be a necessary condition for reliable indirect detection.

D. Exoplanets orbiting stars with consistent emission patterns are less common than those orbiting stars with inconsistent emissions.
If this were true, it would strengthen the conclusion by providing a reason why few exoplanets would be detectable, but it's not a necessary assumption for the logical flow. The conclusion already states "few exoplanets are likely to produce detectable signals," implying some limitation. Even if stable-emission stars were common, the argument's logic about the dependence on stable emissions would still hold.

E. Some exoplanets orbit stars with stable emissions but still fail to produce reliably detectable signals.
This weakens the argument or points to other limiting factors. The argument focuses on the necessity of stable emissions for reliable indirect detection. If stable emissions aren't even enough, it complicates the picture, but it's not an assumption that helps the conclusion follow logically from the premises. The existing argument implies that if the star isn't stable, you won't get reliable data. This option suggests other issues even with stable stars.

Regards,
Lucas
Bunuel
Most known exoplanets lie too far from Earth to be observed directly and must instead be identified using indirect detection methods, such as measuring starlight distortions or subtle gravitational wobbles. However, these methods can generate reliable signal data only if the planet’s host star emits light in stable and consistent patterns over time. Therefore, few exoplanets are likely to produce detectable signals that can be consistently detected unless they are close enough to Earth to be observed directly.

The conclusion above follows logically if which of the following is assumed?

A. Indirect detection methods are less reliable than direct observation when gathering data about planetary atmospheres.
B. There are no alternative methods of detecting reliable signal data from exoplanets other than through shifts in starlight distortions or gravitational wobbles
C. Reliable interpretation of signal-related data depends more on the characteristics of the host star than on the exoplanet itself.
D. Exoplanets orbiting stars with consistent emission patterns are less common than those orbiting stars with inconsistent emissions.
E. Some exoplanets orbit stars with stable emissions but still fail to produce reliably detectable signals.


 


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