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The Moon
The moon’s light.
The sun’s light is reflected off of the moon’s surface.
The different colors on the moon’s surface are caused by the different types of bedrock/regolith.
The Apparent ChangePercentage of illumination – revolution.
Size changes --- shape of the moons orbit.–Large apparent diameter------closer to
Earth–Smaller Apparent diameter—farther
from Earth
Moon Phase Names
• 1 = New Moon
• 2 = First Crescent
• 3 = First Quarter
• 4 = First Gibbous
• 5 = Full Moon
• 6 = Last Gibbous
• 7 = Last Quarter
• 8 = Last Crescent
Sun 1
2
34
5
6
7
8
Earth
Full Moon
First Quarter
Last Gibbous
First Crescent
Lunar Cycle- New Moon to New Moon
29 ½ days
Q: Why do we always see the same side of the moon?
A: Because it rotates at the same rate it revolves. (Pg 15 ESRT)
Q: Why is the period of revolution of the moon 27 1/3 days and the lunar month is 29 ½ days?
Because the Earth is revolving around the Sun at the same time that the Moon is revolving around
the Earth.
https://www.youtube.com/watch?v=nXseTWTZlks
https://www.youtube.com/watch?v=ssA7Ew_BQHY
https://www.youtube.com/watch?v=LaqrQyTm9B4
https://www.youtube.com/watch?v=nXseTWTZlks
– F = force
– G = gravitational constant
– m = mass of object
– r = distance between them
As the distance between two objects doubles, the gravitation force reduces exponentially
𝐹= 𝐺𝑚1𝑚2𝑟2
r = 1 r = 2
𝐹= 𝐺𝑚1𝑚2𝑟2 = ሺ1ሻሺ1ሻ(1)(1) = 1
r = 1 r = 2
𝐹= 𝐺𝑚1𝑚2𝑟2 = ሺ1ሻሺ1ሻ(1)(2)2 = 14
Eclipses• Solar Eclipse
–The moon casts a shadow on the earth.
–Phase of Moon- New Moon
Solar Eclipse
Solar Eclipse from Mir
Christmas Partial Solar Eclipse 2000
Eclipses• Lunar Eclipse
–The earth casts its shadow on the moon
–Phase of moon- Full Moon
Eclipses
• Why eclipses don’t occur every month
• Because the moon’s plane of orbit is on a 5 degree tilt with respect to the Earth’s plane of orbit.
• The moon’s shadow does not reach Earth’s surface when it is at apogee
Lunar Eclipse
Tides• Gravity
– The force of attraction between two masses
– Gravity is directly related to the mass of two objects and the distance between them.
𝐹= 𝐺𝑚1𝑚2𝑟2
•Water on the face of the Earth is pulled by the moon and the Sun.
•The Earth’s rotation causes this force to move the oceans like a large wobbling plate.
•This oscillation causes the water level to periodically rise and fall.
•This is called tides.
•Tides vary from place to place.
•Tides can range from one foot to forty feet every 6 hours.
•The bay of Fundy has forty foot tides.
Tides• Cause of tides
– Water on the surface of the Earth has mass.– The moon’s gravitational force pulls on the
water.– The sun also pulls on the oceans but it is farther
away so its influence is less.
– If the Earth had no moon would we still have tides?
•As the moon orbits the Earth it causes the Average tides to change.
•During a full and new moon the high tides are higher and the low tides are lower.
•During the quarter moon high tides are lower and low tides are higher
Spring Tides at New Moon
SunEarth
New Moon
Higher high tides, lower low tides.
Neap Tides at Quarter Moon
Sun
Earth
Quarter Moon
Higher low tides, lower high tides.
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