kahipz wrote:
There're several questions, taken from
OG Verbal Review 2016, have answer keys whose explanations aren't fully convincing to me. The question below is one in particular. I've provided my reasoning at the end as to why I find the explanations unconvincing. Someone please take a look at point out the flaw in my reasoning. Thanks : )
Question:
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 telescopes can provide.
Answer Key
Two controversial choices (for me)
(B) Ground-based telescopes on mountain summits are still subject to more atmospheric distortion than are space telescopes orbiting above the atmosphere.
(E) CORRECT. This indicates an inherent limitation of space-based telescopes: unlike Earth-based telescopes, they lack the light-gathering capacity that astronomers need to perform one of their primary tasks, i.e., detailed spectral analyses. So Earth-based telescopes are unlikely to soon become obsolete.
My Reasoning:
My initial answer was (B), and still is. As for answer choice (E), I'm unconvinced because the answer choice doesn't point out unambiguously that Earth-based telescopes have that light-gathering capacity that space-based telescopes fall short, even though the explanation just inexplicably claims that capacity for Earth-based telescopes. As a non-expert in this field, I suppose the test takers aren't supposed to infer that space-based and Earth-based telescopes are only two categories of telescopes in a dichotomy, or that Earth-based telescopes inherently have a better light-gathering capacity that the space-based ones.
As for answer (B), from the viewpoint of a domain illiterate, the reference of "make stars appear to twinkle" doesn't come over as downright inferior and worth being rendered obsolete; the answer actually came over as "The problem with atmospheric distortion becomes abated, to whatever extent, when ground-based telescopes are located on mountain summits; hence, can still be of some use". My choice of (B) over (E) bases primarily on the fact that (E) doesn't explicitly claim for ground-based telescopes the capacity that would make it more useful than space-based ones in that particular regard, while (B) explicitly points out how the weakness of ground-based telescopes can be offset.
Thank you : )
Choice B is talking about a particular kind of ground based telescope.(Ground based telescope located on mountains) You dont know how much percentage of Ground based telescope constitute those that are located on the mountains.
I think you are assuming that in near future, all the Ground based telescopes can be migrated to the mountains and hence can be useful. The option does not tell you this.
Also note that, if Space based telescope are already there which can carry out this functionality without any problems that ground based telescope may face, then why will the Ground based telescope be used if same functionality can be achieved by the space based ones .
See to weaken the conclusion, we need to show something that Ground based telescope can do but space based ones cannot, so there will be a reason to use ground based telescope as you cannot achieve that functionality using the space based.
Choice E precisely does that.
It states that Space based telescope may not be useful for analyzing chemical composition of stars .So it presents one drawback for space based telescope.
This functionality can be provided (we are not sure whether ground based can provide this functionality, but still there is a chance) by ground based telescope. So it weakens the conclusion.
We do not need to falsify a conclusion. Any choice that casts some doubt on the conclusion can be a valid Weakener