Moons orbiting the massive planet on the left move faster in their orbits than those orbiting at the same distance from the less massive planet on the right.

• Blue moons' distances are equal.
• Left planet mass = 2 × right planet mass.
• Red moon's speed and right blue moon's speed are equal. Red moon's distance = 2 × blue moon's distance.
• Red moon's orbital period is MORE than 2 × (inner left blue moon's orbital period).
  Kepler's 3rd law: P ~ r^3/2 (not P ~ r !)