Geography Notes: Earth, Sun, and Moon
1. Earth’s Movement Around the Sun
Types of Movement: - Rotation: Earth spins on its axis (~24 hrs) - Revolution: Earth orbits the
sun (~365.25 days) Earths Rotation: - Axis tilted at 23.5; causes day/night - Rotates west to
east; full rotation = 24 hrs - Effect: Day-night cycle and sun's apparent movement Earths
Revolution: - Orbit is elliptical; takes ~36514 days = 1 year - Causes seasons due to tilt +
orbit
2. Gravitational Force Between Earth and Sun
Gravity is the force pulling objects toward each other. Suns Gravity: - Strong pull keeps
planets in orbit - Without it, Earth would drift away Earths Gravity: - Pulls things to
surface - Holds atmosphere, oceans, people in place Balance of Forces: - Earths motion + Suns
pull = stable orbit (like spinning a ball tied to string)
3. The Moon and Its Influence on Earth
The Moon: - Earth's natural satellite; ~384,400 km away - Takes 27.3 days to orbit Earth
Movements: - Rotates + revolves in same time always same face seen Moons Effects: 1. Tides:
Moon's gravity causes high & low tides daily 2. Stabilizes Earth's tilt stable climate Phases
of the Moon: - New Moon: not visible - First Quarter: right half visible - Full Moon: fully
visible - Last Quarter: left half visible Phases change due to Moons position with Earth and
Sun
Summary
Earths Rotation: Causes day and night Earths Revolution: Causes seasons Suns Gravity: Keeps
Earth in orbit Earths Gravity: Holds everything on surface Moon: Affects tides and stabilizes
Earths axis Moon Phases: Caused by moons position
1. Earth’s Movement Around the Sun
Types of Movement: - Rotation: Earth spins on its axis (~24 hrs) - Revolution: Earth orbits the
sun (~365.25 days) Earths Rotation: - Axis tilted at 23.5; causes day/night - Rotates west to
east; full rotation = 24 hrs - Effect: Day-night cycle and sun's apparent movement Earths
Revolution: - Orbit is elliptical; takes ~36514 days = 1 year - Causes seasons due to tilt +
orbit
2. Gravitational Force Between Earth and Sun
Gravity is the force pulling objects toward each other. Suns Gravity: - Strong pull keeps
planets in orbit - Without it, Earth would drift away Earths Gravity: - Pulls things to
surface - Holds atmosphere, oceans, people in place Balance of Forces: - Earths motion + Suns
pull = stable orbit (like spinning a ball tied to string)
3. The Moon and Its Influence on Earth
The Moon: - Earth's natural satellite; ~384,400 km away - Takes 27.3 days to orbit Earth
Movements: - Rotates + revolves in same time always same face seen Moons Effects: 1. Tides:
Moon's gravity causes high & low tides daily 2. Stabilizes Earth's tilt stable climate Phases
of the Moon: - New Moon: not visible - First Quarter: right half visible - Full Moon: fully
visible - Last Quarter: left half visible Phases change due to Moons position with Earth and
Sun
Summary
Earths Rotation: Causes day and night Earths Revolution: Causes seasons Suns Gravity: Keeps
Earth in orbit Earths Gravity: Holds everything on surface Moon: Affects tides and stabilizes
Earths axis Moon Phases: Caused by moons position
