Official Explanation:

Viewing stars from telescopes on Earth is made difficult because of the “twinkle” caused by changes in the visible light from the star as it passes through our atmosphere, where the light is affected by changes in temperature and wind speed. One way to compensate for this is to put telescopes above the atmosphere where there is less distortion of visible light. Astronomers believe that new telescopes, soon to be put in space, will provide unprecedented information about unseen stars and galaxies.

Which of the following, if true, most helps to support the belief of the astronomers?

(A) Most of the stars and galaxies that have yet to be seen through telescopes have remained hidden because of their distance from Earth.
(B) Telescopes placed above Earth’s atmosphere use adaptive optics that shine laser light into the night sky, helping scientists know the path that the light takes to Earth.
(C) The new telescopes depend on infrared light that can detect objects that are moving so fast their light has been shifted out of the visible region of the electromagnetic spectrum.
(D) Changes in temperature and wind speed can lead to substantially incorrect measurements of a star’s location, age, and speed.
(E) A rapidly turning mirror used to make telescopic images clearer by adjusting incoming light will be unnecessary with the newest telescopes.

Question Type: Inference (Assumption family)
Boil It Down: Telescopes on Earth have trouble viewing stars because of the “twinkle” caused by the star passing through our atmosphere Therefore, new telescopes put in space will provide unprecedented information.
Goal: Find the option that most logically connects the evidence to the conclusion.

Analysis:
This is a slightly different wording for a strengthen question, but just imagine that it says, “Which of the following, if true, most strengthens the conclusion.” That should tip you off that this is an assumption family question. As with every assumption family question, we need to figure out the evidence and conclusion first.

Evidence: Current telescopes have troubles with stars because of a twinkle caused from passing through the atmosphere. New telescopes will be placed above the atmosphere.
Assumption: ???
Conclusion: New telescopes being put in space will provide unprecedented information about stars and galaxies.

Now we ask, what is our prompt assuming to come to their conclusion? My immediate focus is on this word “unprecedented.” Unprecedented is an incredible strong word. Strong words tend to create heavy handed conclusions which we can poke holes in. Here, we know that telescopes now have problems with twinkles. But why does the twinkle mean there is some unprecedented information we can’t know without it. Is the twinkle really that bad? For this conclusion to be right, the prompt is necessarily assuming that something about the twinkle prevents us from gaining information we otherwise could not have. Otherwise the information couldn’t be unprecedented! Because we need to strengthen this argument, I want an answer choice that does that exactly. I want my answer choice to say something along the lines of “The twinkle now is so bad that there are millions of stars we can’t currently study.”

(A) Most of the stars and galaxies that have yet to be seen through telescopes have remained hidden because of their distance from Earth.
This is close but brings something up we don’t care about: distance. Does the evidence talk about distance being a problem? No. Does the conclusion? No. Is there anything to suggest that current telescopes are limited by distance? No. Is there anything to suggest that putting telescopes in scope would increase the distance we could see? No. Our focus is on fixing the twinkle. The distance is out of scope.

(B) Telescopes placed above Earth’s atmosphere use adaptive optics that shine laser light into the night sky, helping scientists know the path that the light takes to Earth.
Closer than A, but not quite there yet. Sure, the new telescopes in space could help us find the path the light takes to Earth, but is this unprecedented information? Do we know that, even with the twinkle, current telescopes cannot find the path to Earth? My understanding is that current telescopes can find the path, but the “twinkle problem” just makes it more difficult to see the stars clearly.

(C) The new telescopes depend on infrared light that can detect objects that are moving so fast their light has been shifted out of the visible region of the electromagnetic spectrum.
This is the correct answer. As I mentioned, we need to find why the new telescopes give ‘unprecedented’ information. This gives us our explanation. I’ll admit it’s tricky, but it fits with our evidence and conclusion very neatly. Let’s plug it in.

Evidence: Current telescopes have troubles with stars because of a twinkle caused from passing through the atmosphere. New telescopes will be placed above the atmosphere.
Assumption: The new telescopes depend upon infrared light that can detect objects that are moving so fast their light has been shifted out of the visible region of the electromagnetic spectrum.
Conclusion: New telescopes being put in space will provide unprecedented information about stars and galaxies.

Go back to the prompt where it says that the twinkle is caused by changes in visible light, and the light is affected by changes in temperature and wind speed. This new telescope would make that less of a problem because it can detect faster moving stars. Better yet, if the light had been shifted out of the visible region, that means these objects had never been seen before. If this telescope shows us never before seen objects, we have now found unprecedented information.

(D) Changes in temperature and wind speed can lead to substantially incorrect measurements of a star’s location, age, and speed.
Remember how I criticized the prompt for using too strong a word with ‘unprecedented’? This answer choice has the opposite problem. ‘Can’ is too weak. If it said “Changes in temperature and wind speed always leads to …” we’d have a better answer choice. However, the word ‘can’ does nothing for us here. If this answer choice is true, is it still possible that the current telescopes can have 100% accurate information? The answer is yes, and that means this answer choice has not proven how new telescopes will give us unprecedented information.

(E) A rapidly turning mirror used to make telescopic images clearer by adjusting incoming light will be unnecessary with the newest telescopes.
Okay. So? Maybe this will save money on the new telescopes, but is this guaranteed to give us unprecedented information? Frankly we don’t care if the mirror will be unnecessary, unless the lack of a mirror somehow gives us new information. This is the wrong answer choice to strengthen our argument.


Don’t study for the GMAT. Train for it.
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This is actually a strengthen question, not an assumption question.. Nonetheless, correct answer is C..

The Question is asking us to find some piece of information or Fact that helps to Support the astronomer's belief that:

"the new telescopes, soon to be put in space, will provide unprecedented information about unseen stars and galaxies."

The author really doesn't provide any actual evidence to support this claim. He discusses how it is difficult to view stars from telescopes on Earth because of the "twinkle". This "twinkle" is caused by changes in temperature and wind speed. One way researchers can work around this problem is to put the telescopes above the atmosphere.

But throughout all this discussion of the problems and difficulty of viewing stars from telescopes on Earth, no supporting Fact is given that shows us HOW these new telescopes in space will provide new information about stars and galaxies that have yet to be discovered. The only thing we do know is that placing telescopes above the atmosphere solves some of the problems related to distortion of the visible light coming from the star. Other than this general fact (that applies to all other telescopes before these "new telescopes), there really is nothing to base this Conclusion on.

In order to help support this belief, we need some kind of information that shows us how these "new telescopes" placed in space will provide all types of new info. about stars and galaxies that other telescopes have yet to find.

The argument is similar to a Conclusion that claims a "Plan" will lead to a certain "Goal" or outcome. The astronomers believe that these new telescopes placed into space (the "Plan") will allow the astronomers to see and gather information about stars/galaxies that have yet to be discovered. (the "outcome")

In order to support this belief, we need an answer that makes it more likely that this "Plan" will lead to the "outcome".




-A- "Most of the stars and galaxies that have yet to be seen through telescopes remained hidden because of their distance from Earth."

This is a general fact that was probably true before the new telescopes were even discussed. It is a statement of general fact and might help to explain why it is so hard to see some of the stars and galaxies currently. However, this does not tell us anything about how these "new telescopes" will allow astronomers to find unseen stars and galaxies.


-B- "Telescopes placed above the Earth's atmosphere use adaptive optics that shine laser light into the night sky, helping scientists know the path that the light takes to Earth."

Again, this answer helps to explain one of the premises we are already given. The answer explains why placing current telescopes above the atmosphere is one way to compensate for the distortion of visible light from the star: because these telescopes placed above the atmosphere use "adaptive optics."

Are these adaptive optics part of the "new telescopes" placed in space? And even if we assume they are, will the adaptive optics be useful in space (a location that might not be exactly the same as "above the atmosphere")? We do not have any answers to these questions.

The answer does not provide us with any information that helps us to believe that the new telescopes placed in space will provide astronomers with new access to unseen stars and galaxies.


-D- "Changes in temperature and wind speed can lead to substantially incorrect measurements of a star's location, age, and speed."

Similar to A and B, we are given another Fact that is true before the new telescopes are to be put in space. The answer gives us more of an explanation of why it is difficult to view stars from telescopes on Earth.

But what will the "new telescopes placed in space" do to overcome these problems? This general fact does not give us any more belief that the new telescopes will allow the astronomers to view new unseen stars and galaxies, and collect information on them.


-E- "A rapidly turning mirror used to make telescopic images clearer by adjusting incoming light will be unnecessary with the newest telescopes."

Does not having a "rapidly turning mirror" somehow mean that the new telescopes placed in space will give the astronomers new access to stars and galaxies? We do not have information that could tell us what the effect is of not needing rapidly turning mirrors in the new telescopes.

Maybe not needing these mirrors will allow the new telescopes to have some new awesome power to see stars and galaxies. Or maybe the effect is the same as when the telescopes had these mirrors to adjust the light. We do not know.


-C- "The new telescopes depend on infrared light that can detect objects that are moving so fast their light has been shifted out of the visible region of the electromagnetic spectrum."

C is the only answer that provides us with a Fact about how the new telescopes placed in space will be an upgrade over the currently existing telescopes, such that the new telescopes will provide unprecedented information about stars and galaxies.

We are given the reason why it is difficult to see a lot of stars through telescopes on Earth. The visible light from the star is affected by changes in temperature and wind speed. By having a new telescope in space that can detect objects that are moving so fast that the star's light is made "invisible" (the light is out of the visible region of the electromagnetic spectrum), we have more confidence that any problems that were present before can be overcome with these new telescopes in space.

Since the answer suggests that any existing problems before the new telescope can possibly be overcome by these new telescopes, we have more faith in the astronomer's belief that the new telescopes will allow them to see new stars and galaxies.


C most helps to support the astronomer' belief.

The question setup appears to be borrowed from this official question. But the version presented here doesn't have a good answer. The "OA", C, is clearly not correct, because C does not tell us how the new telescopes differ from the old ones. The new telescopes use infrared, but what do the old telescopes use? We aren't told. If infrared is so good, why aren't the old telescopes using it already? Unless an answer choice tells us how the new telescopes differ from the old, it can't be the right answer to a question like this -- an answer that read "the new telescopes use very good technology" obviously would not be correct, for example, but that is essentially what C says.

C is also a non sequitur. The entire question stem talks about how space telescopes are good because they will receive "visible light" undistorted by the atmosphere. But then C tells us that this one advantage we know space telescopes have, the only reason we had from the stem to think space telescopes are better than ground telescopes, is irrelevant, because the space telescopes don't use "visible light" at all. They use infrared. If C is the right answer, why is the stem even there?

The OE devotes a lot of attention to the meaning of the word "unprecedented", but if shades of meaning are important when considering that one word, they should be important when considering every word. The belief we're trying to support is that new telescopes will provide "unprecedented information about unseen stars and galaxies". Answer C tells us new telescopes can detect "objects that are moving so fast..." Are "stars and galaxies" among the "objects" discussed in answer C? If not, answer C is utterly irrelevant to the astronomers' belief. There's no way to know from what's written in the question what is included among the "objects" answer C describes.

Answer D seems to be the only justifiable answer among the choices, since it clearly suggests the new telescopes will be capable of measurements with less error. Whether that qualifies as "unprecedented information" some might say is debatable, but 'unprecedented' simply means 'never done or known before' according to my dictionary, so any new information, groundbreaking or not, is definitionally 'unprecedented'.
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