Question

nasas cassini probe has detected an unusual wobble in the rotation of mimas, saturns smallest moon. using a computer model to study mimass 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 moons 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? choose 1 answer: a rhoden and colleagues were the first to confirm that several of saturns moons contain hidden oceans. b research has failed to identify signs that there is an ocean hidden beneath the surface of mimas. c rhoden and colleagues created a new computer model that identifies moons with hidden oceans without needing to analyze the moons rotation. d research has revealed that an oddity in the rotation of mimas could be explained by an ocean hidden beneath its surface.

Explanation:

The text starts by stating that NASA's Cassini probe detected an unusual wobble in Mimas's rotation. Then it mentions that using a computer model, Rhoden and colleagues proposed that this wobble could be due to a liquid ocean beneath Mimas's icy surface. Option A is incorrect as the text says "the researchers believe other moons should be examined" (not that they confirmed several already have). Option B is wrong because the text suggests the wobble might indicate an ocean (not that research failed to identify signs). Option C is incorrect as the model was to study Mimas's gravitational interactions and tidal forces (not to identify moons without analyzing rotation). Option D aligns with the text's main idea of the wobble (oddity in rotation) potentially being explained by an ocean beneath Mimas's surface.

Answer:

D. Research has revealed that an oddity in the rotation of Mimas could be explained by an ocean hidden beneath its surface.