Readers discuss Mimas’ hidden ocean and ancient cave art

Hidden depths

Slight changes in the orbit of Saturn’s moon Mimas hint at the presence of a vast, young ocean beneath the satellite’s icy surface that may have formed between 5 million and 50 million years ago, Adam Mann reported in “This Saturn moon may harbor water” (SN: 3/9/24, p. 8).

Reader Bobby Baum asked how the ocean formed so recently and whether an ocean could have formed multiple times in the past.