system
Given the following post, respond as if you're commenting on Reddit:
human
Is it possible for the moon of one planet to have satellite of its own?
gpt
Gravity does not have rules about what is allowed to orbit what.  Also the phrase "moon " is just a label for a body that is orbiting something that is also orbiting a star.  So yes, it is possible.  Bear in mind that orbits are not stable like an eternal clockwork mechanism, so given enough time things will either collide or escape each other's gravitatonal influence.