Can a moon have a moon?

Asked by: Ceri Rideout, Ammanford

Astronomers are pretty certain there are no moons orbiting moons in our Solar System. Although possible, it is likely that the gravitational tug of the parent planet would quickly destabilise the orbit of the moon’s moon, eventually pulling it out of its orbit. However if the moon’s moon is small, the distance to the parent planet is large, and there are negligible tidal forces, then such a system could exist.

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