Discovery of Epimetheus

Epimetheus is a small moon of Saturn that shares almost the same orbit as its neighbour Janus. When the pair was first glimpsed from Earth in late 1966, astronomers believed they had seen a single moon, and the matter was only settled in 1978, when Stephen Larson and John Fountain showed that two bodies were involved. Voyager 1 confirmed this in 1980. Every four years the two moons approach each other and swap orbits, with the inner one moving outward and the other inward, in a rare co-orbital dance. The moon is named after Epimetheus, the brother of Prometheus in Greek mythology.

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