Flexi Says: It is hypothetically possible for a large moon to have its own smaller moon, or submoon. However, scientists have not been able to detect any submoons in our solar system, even for very large moons of Jupiter and Saturn. Therefore, if submoons exist at all, they are very rare. The dynamics of gravitational attraction and orbits of moons and their planets probably make the orbits of any submoons unstable. It is possible that submoons may exist for a relatively short time before being pulled out of their orbits.