NASA's Cassini probe has detected an unusual wobble in the rotation of Mimas, Saturn's smallest moon. Using a computer model...
GMAT Information and Ideas : (Ideas) Questions
NASA's Cassini probe has detected an unusual wobble in the rotation of Mimas, Saturn's smallest moon. Using a computer model to study Mimas's gravitational interactions with Saturn and tidal forces, geophysicist Alyssa Rhoden and colleagues have proposed that this wobble could be due to a liquid ocean moving beneath the moon's icy surface. The researchers believe other moons should be examined to see if they too might have oceans hidden beneath their surfaces.
Which choice best states the main idea of the text?
Rhoden and colleagues were the first to confirm that several of Saturn's moons contain hidden oceans.
Research has failed to identify signs that there is an ocean hidden beneath the surface of Mimas.
Rhoden and colleagues created a new computer model that identifies moons with hidden oceans without needing to analyze the moons' rotation.
Research has revealed that an oddity in the rotation of Mimas could be explained by an ocean hidden beneath its surface.
Step 1: Decode and Map the Passage
Part A: Create Passage Analysis Table
| Text from Passage | Analysis |
|---|---|
| "NASA's Cassini probe has detected an unusual wobble in the rotation of Mimas, Saturn's smallest moon." | What it says: NASA probe detected unusual wobble in Mimas rotation What it does: Introduces an unexpected observation about Saturn's moon What it is: Opening observation/discovery |
| "Using a computer model to study Mimas's gravitational interactions with Saturn and tidal forces, geophysicist Alyssa Rhoden and colleagues have proposed that this wobble could be due to a liquid ocean moving beneath the moon's icy surface." | What it says: Rhoden team use model and propose wobble equals possible hidden ocean What it does: Presents a scientific explanation for the wobble What it is: Proposed hypothesis/explanation |
| "The researchers believe other moons should be examined to see if they too might have oceans hidden beneath their surfaces." | What it says: Researchers suggest checking other moons for hidden oceans What it does: Extends the implications beyond just Mimas What it is: Future research suggestion |
Part B: Provide Passage Architecture & Core Elements
Main Point: Scientists have discovered that an unusual wobble in Saturn's moon Mimas could be evidence of a hidden ocean beneath its icy surface.
Argument Flow: The passage moves from observation to explanation to broader implications. We start with NASA's discovery of something odd about Mimas's rotation, then learn about scientists' proposed explanation involving a hidden ocean, and finally see how this could apply to other moons as well.
Step 2: Interpret the Question Precisely
What's being asked? The main idea of the entire text
What type of answer do we need? A statement that captures the central message or most important point
Any limiting keywords? N/A
Step 3: Prethink the Answer
- The passage is fundamentally about a scientific discovery and its explanation
- The key elements a correct answer must have are:
- Reference to the unusual wobble/rotation oddity in Mimas
- Connection to the proposed explanation (hidden ocean)
- Recognition that this is research/scientific work - The answer should say something like: scientists discovered an odd rotation pattern in Mimas and believe it could be explained by a hidden ocean
Rhoden and colleagues were the first to confirm that several of Saturn's moons contain hidden oceans.
- Claims Rhoden was first to confirm multiple moons have hidden oceans
- The passage only discusses Mimas, not multiple confirmed discoveries
- Says they confirmed when the passage uses proposed
Research has failed to identify signs that there is an ocean hidden beneath the surface of Mimas.
- Says research failed to identify signs of an ocean
- Directly contradicts the passage, which says they found the wobble could be explained by an ocean
Rhoden and colleagues created a new computer model that identifies moons with hidden oceans without needing to analyze the moons' rotation.
- Claims they created a model that works without needing to analyze rotation
- The passage specifically says they studied the rotation wobble using their model
Research has revealed that an oddity in the rotation of Mimas could be explained by an ocean hidden beneath its surface.
- Mentions the oddity in rotation which matches the unusual wobble
- Says it could be explained by an ocean which matches the tentative proposed language
- Captures both the discovery and the proposed explanation