The Moons of Mars, Foretold in Gulliver's Travels
In 1726, Jonathan Swift wrote that astronomers had discovered two moons circling Mars. No one would see them for another 151 years.
What was reported
In Gulliver's Travels, published in 1726, the Irish writer Jonathan Swift describes the flying island of Laputa, whose astronomers have discovered 'two lesser stars, or satellites, which revolve about Mars'. He even gives their distances and how long they take to go round.
In 1877, the American astronomer Asaph Hall discovered that Mars does have two small moons, which he named Phobos and Deimos. They're tiny and close to the planet, and very hard to see.
Explanations offered
Swift's numbers aren't right, and he was probably drawing on an older idea: Johannes Kepler had suggested Mars might have two moons, reasoning that if Earth has one and Jupiter four, Mars should have two. The match is a celebrated lucky guess. Two craters on Deimos are now named Swift and Voltaire.
- When
- Written in 1726; found in 1877
- Where
- Dublin, Ireland
- Witnesses
- Readers of Jonathan Swift
- Status
- Coincidence
Famous cases are real, widely reported events. Each file sets out what witnesses said and the explanations that have been offered, without taking a side.
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