Quote:
Originally Posted by Johnny Angel
So, if both moons were equal size... they'd need to be within each other's Hill Sphere...?
|
That's right. And well inside. The Hill sphere is defined by neglecting the mass of the third body; even so orbits in the outer half or two thirds are not stable over geological time. Two moons of equal mass are likely to excite nasty three-body-problem effects. You want to place them snugly to stop them from wandering off.