Ferdinand, a moon of Uranus

Ferdinand is the most distant known moon of Uranus and follows a retrograde orbit, travelling in the opposite direction to the planet’s rotation. At around 21 kilometres (13 miles) in diameter, it is a small and faint irregular moon.

Ferdinand was discovered in 2001 by Matthew J. Holman and J. J. Kavelaars, using the Canada-France-Hawaii Telescope at Mauna Kea Observatory, Hawaii. Because of its extreme distance from Uranus, it takes almost eight Earth years to complete a single orbit.

Its retrograde, inclined, and elongated path suggests that Ferdinand is a captured object, possibly originating in the Kuiper Belt or as a leftover from the early Solar System. Its capture history may be linked to other distant Uranian moons, although its orbit is more extreme than most.