Astronomers have found new evidence that the number of galaxies in the universe is not 10 billion, as previously beli...

Annie on February 12, 2020

Hi @shafieiava,

(A) is correct because it explains the apparent dilemma in the argument. We are told that astronomers now think that there are 50 billion galaxies in the universe, instead of just 10 billion. Then we are told that many astronomers don't think this changes the total mass of the universe. How can these both be true? Well, they can both be true if the mass of the galaxies doesn't really affect the mass of the universe. Answer (A) states this.

(D) is incorrect but tricky. The middle sentence of the stimulus tells us that the discovery of more galaxies will have an important effect on theories of how galaxies are formed BUT the question asks about the third sentence, aka why astronomer's estimates of the universe's mass won't change. This answer choice tries to mix these two ideas together, but in reality the middle sentence is just there to throw you off, and it does not tell us anything about the mass of the universe.

Ava on February 18, 2020

Thanks for your help. Does this mean that the conclusion of the argument is the last sentence? I was under the impression that the second sentence, which you have identified as essentially fluff was the conclusion? Thanks in advance.