Astronomer: Astronomical observatories in many areas have become usele

Question

Astronomer: Astronomical observatories in many areas have become useless because light from nearby cities obscures the stars. Many people argue that since streetlights are needed for safety, such interference from lights is inevitable. Here in Sandsville, however, the local observatory’s view remains relatively clear, since the city has restricted unnecessary lighting and installed special street lamps than direct all their light downward. It is therefore possible to have both well-lighted streets and relatively dark skies.

The astronomer’s argument proceeds by

(A) appealing to scientific authority to challenge a widely held belief

(B) questioning the accuracy of evidence given in support of the opposing position

(C) proposing an alternative scientific explanation for a natural phenomenon

(D) making a distinction between terms

(E) offering a counterexample to a general claim

GmatKnightTutor · Answer

The passage starts by talking about observatories not being able to see the stars well because of city light. It tells you how MANY PEOPLE argue that because SL are needed such light interference is INEVITABLE. The argument ends by giving an example of a place where we have both SL and good observatory star viewing.

Astronomer: Astronomical observatories in many areas have become useless because light from nearby cities obscures the stars. Many people argue that since streetlights are needed for safety, such interference from lights is inevitable. Here in Sandsville, however, the local observatory’s view remains relatively clear, since the city has restricted unnecessary lighting and installed special street lamps than direct all their light downward. It is therefore possible to have both well-lighted streets and relatively dark skies.

The astronomer’s argument proceeds by

(A) appealing to scientific authority to challenge a widely held belief
I could be wrong here, but a SCIENTIFIC AUTHORITY would probably be some organization or esteemed professor or something to increase the credibility of one's argument. Regardless, nothing like that seems to be the case here.

(B) questioning the accuracy of evidence given in support of the opposing position
This one really stuck with me for a while. I couldn't shake it. You see the whole point of the MANY PEOPLE was that because street lights are needed light interference was INEVITABLE. The argument, however, says that you can have SL without it being INEVITABLE basically. So the accuracy of the initial claim is hurt. However, there are some issues here. First, is the accuracy of the opposing view being questioned? Nope, at least not directly I think. If the argument had said something along the lines of "while I agree that most SL cause light interference not all of them do" we might have had some more cause to choose this. The argument, however, simply provides a counter example, so (E) wins.

(C) proposing an alternative scientific explanation for a natural phenomenon
Alternative scientific explanation? Where? Nope. Easy elimination.

(D) making a distinction between terms
Nope. Another easily elimination. No term distinction issues that I can see.

(E) offering a counterexample to a general claim
Yes, the answer. The general claim is that SL cause LI and that this is inevitable. The argument provides an example that counters this.

AnirudhaS · Answer

General claim - Astronomical Observatories have become useless because there is too much light from nearby cities.
Counter-example - Example of Sandsville, where with the usage of special lights coupled with restriction of unnecessary lighting have kept the Observatories working with minimum interference.
IMO  E  fits best.

shameekv1989 · Answer

Astronomer: Astronomical observatories in many areas have become useless because light from nearby cities obscures the stars. Many people argue that since streetlights are needed for safety, such interference from lights is inevitable. Here in Sandsville, however, the local observatory’s view remains relatively clear, since the city has restricted unnecessary lighting and installed special street lamps than direct all their light downward. It is therefore possible to have both well-lighted streets and relatively dark skies.

The astronomer’s argument proceeds by

(A) appealing to scientific authority to challenge a widely held belief

(B) questioning the accuracy of evidence given in support of the opposing position

(C) proposing an alternative scientific explanation for a natural phenomenon

(D) making a distinction between terms

(E) offering a counterexample to a general claim

General Claim :-  
Astronomical observatories in many areas have become useless because light from nearby cities obscures the stars.

What People argue :-  
 Premise  :- Since streetlights are needed for safety, 
 Conclusion  :- Such interference from lights is inevitable.

Author argues :-  
 Premise  :- This city has restricted unnecessary lighting and installed special street lamps which helps in the local observatory’s view to remain relatively clear. 
 Conclusion  :- It is therefore possible to have both well-lighted streets and relatively dark skies.

I was stuck between B and E.

I eliminated B on the basis that for the oposing position (Light is inevitable) the premise given is "streetlights are needed for safety". Author is not arguing that the lights are not needed for safety. He is just providing another way by which the streetlights can provide safety as well as be restricted to the land area which can provide a better view to the astronomers.

E because author has provided a counterexample to a general claim that observatories have become useless

rahat16 · Answer

Here astronomer introduces a reason that observataries in many areas has become useless becasue of street lighting . Then she goes on to say this problem doesn't exist in Sandsville ,becasue street lights direct light downward and finally concludes that both well-lighted streets and relatively dark skies are possible. The example of other cities vs sandville raises contradiction becasue even in other areas street light can point downwards to have both the things - will-lighted streets and clear skies.

(A) appealing to scientific authority to challenge a widely held belief ---Author is not challenging anything

(B) questioning the accuracy of evidence given in support of the opposing position - nothing being questioned

(C) proposing an alternative scientific explanation for a natural phenomenon - OOS

(D) making a distinction between terms - no distinction is made between any of the terms mentinoed in argument

(E) offering a counterexample to a general claim  -this is correct

HarshaGM · Answer

As per me, the correct answer is option (E).

Understanding the passage:

1. Astronomer's view: Astronomical observatories in many areas have become useless because light from nearby cities obscures the stars. 
2. Claim of many people: such interference from city light is inevitable, because streetlights are  needed for safety 
3. Astronomer's counter example: In Sandsville, observatory's view is clear, even though safety is not compromised
 How: 
 a) Sandsville has restricted unnecessary lighting
 b) Special street lamps that direct all light downward (means no light goes upwards/outwards impeding the view of the observatory
4. Astronomer's conclusion: It is possible to have both well-lighted streets (thus no compromise on safety) and dark skies (needed for astronomical observatories).

Question:  Find the mechanism or structure of the astronomer's argument.

Thought Process: 
As we can see, the author has simply provided a counter-example that serves to invalidate/nullify the claim of many people. This is the exact mechanism at play here.

Let us now look at the options.

(A) appealing to scientific authority to challenge a widely held belief

Irrelevant. The only two entities here are the astronomer, and the general public. The passage makes no mention of a scientific authority, hence this cannot be the mechanism of the astronomer's arguement.

(B) questioning the accuracy of evidence given in support of the opposing position

Interesting choice.  But, the astronomer is questioning a claim made by the general public, he is not questioning any evidence in this argument . He does not mention any evidence from the opposition, but only the claim in this argument. Hence, this is not the correct mechanism.

(C) proposing an alternative scientific explanation for a natural phenomenon

Irrelevant. The only natural phenomenon here is the dispersion of light from streetlamps. The astronomer does not provide an alternate scientific explanation for this. All he provides is a counter example, where the city uses a type of streetlamps that changes how light gets dispersed (only downwards). But this is not an alternate scientific explanation for how dispersion of light occurs.  More importantly, this has nothing to do with the mechanism used in the argument to justify his conclusion.

(D) making a distinction between terms

Irrelevant. The astronomer does not mention any terms as such to differentiate. This is definitely not the correct choice.

(E) offering a counterexample to a general claim

This matches our analysis. The astronomer first presented a general claim (made by most people - interference is inevitable, because, safety)), and then provided a counterexample (Sandsville) to debunk the general claim (by saying that interference is not inevitable, can be avoided, even with safety).

Hope this helps. 
Cheers!

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Astronomer: Astronomical observatories in many areas have become usele

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