Astronomers have created a mathematical model for determining whether

Question

Astronomers have created a mathematical model for determining whether life exists outside our solar system. It is based on the assumption that life as we know it can exist only on a planet such as our own, and that our sun, which has nine planets circling it, is the kind of star commonly found throughout the universe. Hence it is projected that there are billions of planets with conditions similar to our own. So astronomers have concluded that it is highly probable, if not virtually certain, that life exists outside our solar system. Yet there has never been detected so much as one planet beyond our solar system. Hence life exists only on planet Earth.

Which one of the following would most weaken the above argument?

(A) Thousands of responsible people, people with reputations in the community to protect, have claimed to have seen UFOs. Statistically, it is virtually impossible for this many people to be mistaken or to be lying.

(B) Recently it has been discovered that Mars has water, and its equatorial region has temperatures in the same range as that of northern Europe. So there may be life on Mars.

(C) Only one percent of the stars in the universe are like our sun.

(D) The technology needed to detect planets outside our solar system has not yet been developed.

(E) Even if all the elements for life as we know it are present, the probability that life would spontaneously generate is infinitesimal.

Source:   Nova GMAT

Sajjad1994 · Accepted Answer

Official Explanation

This argument implies that since no planet has been discovered outside our solar system, none exist and therefore no life exists elsewhere in the universe. Hence the burden of proof is shifted from the arguer to the astronomers.

Although  choice (A)  weakens the argument, it has a flaw: the UFOs may not be life forms.  Choice (B)  is irrelevant. Although the argument states that the only life in the universe is on Earth, it is essentially about the possibility of life beyond our solar system.  Choice (C)  also weakens the argument. However, one percent of billions is still a significant number, and it is not clear whether one percent should be considered “common.” Since a GMAT answer must be indisputable, there is probably a better answer choice. The underlying premise of the argument is that since no other planets have been detected, no others exist.  Choice (D)  attacks this premise directly by stating that no planets outside our solar system have been discovered because we don’t yet have the ability to detect them. This is probably the best answer, but we must check all the choices.  Choice (E)  strengthens the argument by implying that even if there were other planets it would be extremely unlikely that they would contain life. The answer, therefore, is  (D) .

At this time, I would like to discuss the relative difficulty of the problems we have been studying. You may feel that the arguments have been fairly easy. However, they have the same level of difficulty as those on the GMAT. When arguments are classified by the method of reasoning used, their underlying simplicity becomes apparent, and with sufficient study, everyone can master them.

Answer: D

sobby · Answer

Between B and D...
Key point to notice :Argument is about finding a planet beyond our solar system ...So B is incorrect as mars is a part of our solar system ..
D correctly conveys that we don't have any technology to explore planets outside our solar system .
So D

valardohaeris · Answer

In the stimulus, it is already stated that we know that there must be some planets with habitable zones, but unless we detect life there, we can't be sure about it. Based on this, B is ruled out as it says the same thing, possibility. D clearly states that the conclusion is drawn without an investigation with proper technology. So D IMO. Can you please reveal OA

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David H · Answer

The question is set up very easily to lead from one premise to the next, which allows for pretty quick conclusions to be drawn. The focus of the argument should be on the last two sentences that basically say: because life has yet to be detected, life does not exist outside of earth.

Here is the biggest gap in logic. Just because you can't detect something doesn't mean it's not there. It's a rather question begging argument (circular reasoning, tautological argument, whatever you want to call it). So to best weaken and undermine the argument we have to attack this conclusion directly, which answer choice D does, in addition to incorporating the first half of the argument, which says, "... astronomers have concluded that it is highly probable... that life exists outside our solar system."

While answer choice B says, "well, there could be life on Mars," answer choice D more firmly addresses the issue at hand.

aka14 · Answer

Can anyone tell me the conclusion of this passage as in the end astronomer conclude that highly possible to have life

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Abhishek009 · Answer

Astronomers have created a mathematical model for determining whether life exists outside our solar system. It is based on the assumption that life as we know it can exist only on a planet such as our own, and that our sun, which has nine planets circling it, is the kind of star commonly found throughout the universe.   Hence it is projected that there are billions of planets with conditions similar to our own. So astronomers have concluded that it is highly probable, if not virtually certain, that life exists outside our solar system.     Yet there has never been detected so much as one planet beyond our solar system.     Hence life exists only on planet Earth.

Here the blue part represents a Premise and the Red part Indicates a Counter Premise and the Green Part " Life exists only on our planet (In our solar system) " is the main conclusion....

VerbalBot · Answer

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Astronomers have created a mathematical model for determining whether

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