Which one of the following scientific episodes is most analogous to the discovery of Neptune, as that episode is desc...

DavidW on February 29, 2020

Choice E

Hi! Could you please elaborate on why answer choice E is the correct answer? Thanks so much!

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SamA on February 29, 2020

Hello @DavidW,

Let's talk about the Neptune example. Astronomers tried to predict the orbit of Uranus. Based on what? Newton's laws, and various other assumptions. One of these assumptions was that there was no other planet in the vicinity.

When the astronomers prediction failed, we know that something went wrong. Was it Newton's law, or one of the assumptions that was incorrect? (This is what the author of passage A was talking about in the second paragraph.) The astronomers changed one of their assumptions, accepting the possibility of another planet in the vicinity. Sure enough, Neptune was discovered.

We want a parallel argument. We should look for a failed prediction and a new discovery based on that failure.

Answer choice E has these elements. It is difficult to see because the prediction here is implied. They are predicting the proton and the electron to have the same energy as the original neutron. It doesn't, so something in their calculation must be off. Is it the law of conservation of energy, or something else? Pauli introduced the possibility that a third particle was created. (The assumption that only a proton and electron were created was changed.) The third particle was then discovered.

I think this is a tricky set of passages. Keep up the good work!

DavidW on February 29, 2020

Very helpful. Thank you, Sam!