Question 95·Medium·Rhetorical Synthesis
While researching a topic, a student has taken the following notes:
- The Hubble Space Telescope (HST) was launched in 1990 and orbits Earth roughly every 95 minutes.
- A 1993 servicing mission corrected the telescope’s optics, dramatically improving image quality.
- By observing Cepheid variable stars in distant galaxies, HST helped refine the value of the Hubble constant (the rate at which the universe expands).
- The refined constant allowed astronomers to estimate the universe’s age at about 13.8 billion years.
- HST has also produced famous deep-field images, revealing thousands of previously unseen galaxies.
The student wants to emphasize the Hubble Space Telescope’s contribution to determining the age of the universe. Which choice most effectively uses relevant information from the notes to accomplish this goal?
For rhetorical synthesis questions based on notes, first underline the goal in the question (for example, "emphasize contribution to determining the age of the universe"). Then scan the notes and mentally group the ones that clearly serve that goal; ignore interesting but irrelevant facts. Finally, choose the option that uses the most important relevant notes and explicitly connects them in a clear way, and eliminate choices that only mention background details (dates, locations, general features) without fulfilling the stated purpose.
Hints
Clarify the task
Focus on the phrase "contribution to determining the age of the universe." Which notes are about figuring out how old the universe is, not just about images or orbits?
Find the key notes
Look for notes that mention a specific measurement or calculation that leads to an estimate of the universe’s age. Which notes describe that chain of reasoning?
Check the answer choices for that chain
Pick the option that connects what Hubble observed to a refined measurement and then to a specific age for the universe. Ignore choices that only talk about repairs, images, or how often it orbits Earth.
Step-by-step Explanation
Identify the writing goal
The prompt says the student wants to emphasize the Hubble Space Telescope’s contribution to determining the age of the universe. That means the best sentence must focus on:
- What Hubble did, and
- How that action helped figure out how old the universe is.
Details about orbit time, repairs, or pretty pictures are not the main focus unless they clearly connect to determining the universe’s age.
Locate the most relevant notes
Look back at the bullet points and ask: which ones are directly about determining the age of the universe?
Those are:
- Hubble observed Cepheid variable stars in distant galaxies.
- This helped refine the value of the Hubble constant (the universe’s expansion rate).
- The refined constant allowed astronomers to estimate the universe’s age at about 13.8 billion years.
A strong answer will combine these ideas: Hubble’s observations → refined Hubble constant → age of the universe.
Match the choice that uses those key notes
Now scan the options for the one that actually mentions Hubble’s observations (Cepheid variables), the Hubble constant, and the resulting age of the universe (about 13.8 billion years). Only choice B includes both the specific observation and the final age estimate, clearly showing Hubble’s contribution to determining that age. Therefore, the correct answer is B: Among its many achievements, the Hubble Space Telescope observed Cepheid variables that allowed astronomers to refine the Hubble constant and thus calculate the universe’s age to be roughly 13.8 billion years.