# Moon

• A moon is a large object revolving around a planet
• Roughly $\frac{1}{3}$ of the moons in the outer solar system are in direct orbits
• Regular orbit
• Revolve west --> east
• Major of the moons are irregular
• Retrograde orbit (east --> west)
• Orbit has high eccentricity
• More elliptical than circular
• High inclination
• Moving in and out of the planet's equatorial plane
• Irregular moons are mostly located relatively far from their planet
• Probably formed elsewhere and were captured by the planet