Question 202·Hard·Rhetorical Synthesis
While researching a topic, a student has taken the following notes:
- In the late 1960s and early 1970s, astronomer Vera Rubin measured the rotation curves of spiral galaxies.
- She found that stars far from galactic centers orbit at nearly the same speed as stars close to the centers.
- These results conflicted with predictions based solely on the gravitational pull of visible matter.
- Rubin’s observations provided persuasive evidence for the presence of unseen “dark matter.”
- Her work led to the broad acceptance of the dark matter hypothesis within the astronomical community.
The student wants to craft a sentence that highlights the scientific impact of Rubin’s research. Which choice most effectively uses relevant information from the notes to accomplish this goal?
For rhetorical synthesis questions like this, first underline what the prompt wants the sentence to do (for example, highlight scientific impact, summarize a process, or describe a goal). Then quickly scan the notes and mark the few bullets that directly relate to that task, especially any that show cause-and-effect or changes in thinking. When you evaluate the answer choices, eliminate those that (1) leave out the key consequence or result, (2) focus on less important details, or (3) introduce claims not supported by the notes. The correct choice will usually combine multiple important notes and clearly match the stated purpose in the question.
Hints
Focus on the task word: impact
The question asks for a sentence that highlights the scientific impact of Rubin's research. Ask yourself: which notes describe not just what she did, but how it changed astronomers' understanding?
Locate the “effect on the community” in the notes
Look closely at the last two bullet points: what do they say Rubin's observations were evidence for, and how did the astronomical community respond?
Match both finding and consequence
Eliminate choices that only talk about her measurements or only talk about influence without explaining what specifically changed. Look for an option that combines her surprising result with the change in scientific thinking.
Watch for unsupported claims
Be careful of any answer that introduces details about her influence or reputation that are not explicitly stated in the notes.
Step-by-step Explanation
Understand the task
The question asks for a sentence that highlights the scientific impact of Vera Rubin's research.
That means the right choice must not only state what she observed, but also show how those observations affected scientific understanding or the astronomy community.
Identify the key ideas in the notes
From the notes, pull out the most important points:
- Rubin measured rotation curves of spiral galaxies.
- She found that stars far from galactic centers move at nearly the same speed as inner stars.
- These findings conflicted with predictions based only on visible matter.
- Her observations gave strong evidence for unseen dark matter.
- Her work led to broad acceptance of the dark matter hypothesis among astronomers.
To highlight scientific impact, the sentence should connect her measurements and surprising result to the acceptance of dark matter.
Clarify what “scientific impact” requires
A sentence showing scientific impact should answer two questions:
- What did she discover or show? (the scientific finding)
- How did that change scientific thinking or the community? (the impact)
So the best answer will:
- Mention her measurements or findings, and
- Explicitly show that these prompted acceptance of dark matter or changed astronomical models.
Evaluate each answer choice against the notes and the goal
Now compare each option to the notes and the idea of scientific impact:
- Choice A focuses on her finding and that it challenged gravitational models, but it does not mention dark matter or the community’s response, so it underplays the impact described in the notes.
- Choice B mentions conflict with predictions and says her work remains influential, but “remains influential today” is not in the notes, and it never says how it influenced science (no mention of dark matter or what changed).
- Choice C talks about astronomers widely citing her work and says visible matter alone cannot explain rotation, but it is vague about what she actually measured and never mentions dark matter or the shift to that concept, which the notes emphasize.
- Choice D clearly states that her measurements revealed nearly uniform stellar speeds and that this prompted astronomers to embrace invisible dark matter, directly capturing both her findings and their major scientific impact.
Therefore, the best answer is: Vera Rubin’s measurements of spiral galaxies’ rotation curves revealed unexpectedly uniform stellar speeds, prompting astronomers to embrace the concept of invisible dark matter.