Which is the right answer and why others are wrong?

Images from ground-based telescopes are invariably distorted by the Earth’s atmosphere. Orbiting space telescopes, however, operating above Earth’s atmosphere, should provide superbly detailed images. Therefore, ground-based telescopes will soon become obsolete for advanced astronomical research purposes.

Which of the following statements, if true, would cast the most doubt on the conclusion drawn above?

(A)An orbiting space telescope due to be launched this year is far behind schedule and over budget, whereas the largest ground-based telescope was both within budget and on schedule.

(B)Ground-based telescopes located on mountain summits are not subject to the kinds of atmospheric distortion, which, at low altitudes, make stars appear to twinkle.

(C) By careful choice of observatory location, it is possible for large- aperture telescopes to avoid most of the kind of wind turbulence that can distort image quality.

(D)When large-aperture telescopes are located at high altitudes near the equator, they permit the best Earth-based observations of the center of the Milky Way Galaxy, a prime target of astronomical research.

(E)Detailed spectral analyses, upon which astronomers rely for determining the chemical composition and evolutionary history of stars, require telescopes with more light-gathering capacity than space telescope can provide.

Beginner Asked on January 5, 2017 in Critical Reasoning.
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3 Answer(s)

Please ask specific questions. What part did you understand? What part did you not?

Also, please provide the official answers when you ask questions.

Expert Answered on January 6, 2017.
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Sure, this question is from VR17. The official answer is E, which I have also marked but I am unable to eliminate the rest.
Why are C and D incorrect? They do provide some info in favour of ground telescopes.

Also, for E, how do we know that ground telescopes have more light-gathering capacity. It might be possible that another space telescope needs to be built for it and will eventually lead to ground telescopes being obsolete.


Beginner Answered on January 6, 2017.
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C – what about other distortions ? the argument talks about atmospheric distortions not wind distortions. Option C still does not address the issue. Secondly it mentions “careful selection of locations” – are such locations available?

D – “the best Earth-based observations of the center of the Milky Way Galaxy” better than space-based? We do not know.

E – you are not looking at making the argument airtight. Moreover, what other locations can telescopes have? they can either be on the ground or in space.

Expert Answered on January 6, 2017.
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