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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…