What have hobbit Bilbo Baggins and the largest sattelite in the Solar system got in common?

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What have hobbit Bilbo Baggins and the largest sattelite in the
Solar system got in common?
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The Lord of the Rings became immensely popular in the 1960s and has remained so ever since, ranking as one of the most popular works of fiction of the twentieth century, judged by both sales and reader surveys. [...]
But how many people know the answer to the question above? What about raven and writing-desk?