Universe & space

Discovery of Sinope

21 July 1914

Sinope is one of Jupiter's irregular outer moons, found by the American astronomer Seth Nicholson at the Mount Wilson Observatory in California. It follows a distant, tilted orbit in the retrograde direction, opposite to Jupiter's rotation, which suggests that it is a captured body rather than one formed alongside the planet. Sinope is small, only a few tens of kilometres across, and belongs to the Pasiphae group of retrograde moons, which may be fragments of a single broken-up object. It was long known simply as Jupiter IX and received its present name in 1975, after a nymph from Greek myth whom Zeus pursued.

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