As solar systems form, planets amass moons in similar ways as stars collect planets. They can form out of the dust and gas that might be forming a disk around a giant planet, they can form as a result of a collision between growing planets, or they can be captured from whatever is passing by.
In this case, I capture them and put them into orbit LIKE A GOD.
large: 20x20mm, 18-20in adjustable sterling chain
med: 12x12, 17-20in adjustable sterling chain
sterling silver, stones vary