Moon Formation Theories
Fission Theory Moon breaks off from Earth
Problems? Earth rotation too slow
Capture Theory Earth’s gravitational pull
Problems? Need extended Earth atmosphere
Giant Impact Theory Proto-Earth is hit
Accretion forms moon
Problems? Undetermined relative sizes
Physical Features
Diameter 3.5 km (1/4 Earth)
Surface Area < .1% of Earth
Orbital Period 27.3 days
Surface Gravity 17% of Earth
So what is so special about the
moon, anyways?
Lunar Cycle
Repeats every 29.5 days
Synodic Period
Harvest Moon
Waning
Decreasing size
Waxing
Increasing size
Ocean Tides
High Tide
Two “bulges”
Elevated Sea Level
Low Tide
Water rushes to
bulges
Earth Rotation
Friction on seafloor