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Space

Mars may have captured and split a comet to create its two moons

How the Red Planet acquired its two moons, Phobos and Deimos, is unknown – they could have formed after something collided with the planet, or started out as asteroids – but now there is a hint of a cometary origin

By Jonathan O’Callaghan

28 March 2024

Mars and it's two moons, Phobos and Deimos

Mars has two irregularly shaped moons, an inner moon named Phobos and an outer moon named Deimos

NASA/JPL-Caltech/GSFC/Univ. of Arizona

The two moons of Mars may once have been a single comet that was ensnared and split by the planet – and an upcoming mission could find out for certain.

How Mars got its two moons, Phobos and Deimos, is a bit of a mystery. They are small, 27 and 15 kilometres across respectively, and both orbit around the planet’s equator. Astronomers have suggested that they may have formed after a collision on Mars’s surface, similar to how Earth’s…

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