Hearing about the moonlet targeted by the DART spacecraft reminded me of a recent video discussing whether exomoons could have their own moons. It was a piece by Cool World Labs titled “Can Moons Have Moons?” It gets into the “Hill Sphere,” which is an astronomical body’s region in which it dominates the attraction of satellites. It can get pretty complex, as the drawing above demonstrates, but its an interesting concept that has yet to be proven in our own solar system or elsewhere. Given that Cool World Labs is already finding exomoons, it may be only a matter of time before we experience these submoons.
Our Awesome Universe 