Transcript The Moon

The Earth-Moon System
Moon
Mass
7.3483 x 1022 kg
Equatorial Radius 1737.4 km
Earth
Mass 5.97219 x 1024 kg
Mean Radius 6371.00 km
Orbital Parameters
Average distance from Earth 384,400 km (0.00257 A.U.)
Perigee
363,300 km
Eccentricity
0.05490
Orbital Inclination to Ecliptic
5.145 degrees
Sidereal Orbit Period
27.321661 Earth days
Sidereal Rotation Period
27.321661 Earth days
Equatorial Inclination to Orbit
6.68 degrees
Origin of the Moon
• Likely formed after a Mars-sized body
collided with Earth
• Moon formed out of the debris
Phases of the Moon
Phases
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Synodic month 29.53 days
Sidereal Lunar Orbit 27.32 days
Actual period variable – perturbations
Moon and Sun both subtend ~0.5 degrees
Eclipses – Lunar, Solar
Occur when moon curs ecliptic, twice a
year
• Approximately 4 to 7 eclipses per year
Total Solar Eclipse 1999
Tides in Fundy Bay
Different Types
of Tides
Semidiurnal
Mixed Tide
Diurnal
Tidal Forces
What causes tides
• Main constituent Principal Lunar
Semidiurnal
• 12 hr 25 min period
• Slightly longer than 12 hrs due to Lunar
orbit – same direction as Earth’s spin
• Other effects – Sun’s gravity, inclination of
Earth’s spin, moon’s orbit, variation in
distances
• Coastline
Spring and Neap Tides