The theory behind the creation of many of the planets in our solar system is accretion. This theory seems plausible and consistent with the laws of gravity, forces, and capture dynamics. There are three basic methods of satellite capture. The force of gravity caused by an object gets weaker as you move farther away from that object. The Moon pulls more strongly on the side of the Earth facing the Moon than on the side facing away from the Moon.
Tidal forces depend on the radius.
The force raising a tidal bulge is inversely proportional to the quantity of the radius raised to the third power and the entire tidal interaction is inversely proportional to the quantity of the radius raised to the sixth power. As indicated above, as the satellite approaches the planet, the tidal force grows strong. The self-gravity is the same regardless of the distance from the planet. For example, all of the rings of Saturn are inside Roche's Limit. Another way of looking at this is that being inside Roche's limit prevents scattered debris from accreting together.