The Moon

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The Moon
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Crater Formation
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Phases of the Moon
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Identify the Phases

• Crescent Moon - when we can see only a sliver of
  the moon's disk (the side of the moon facing us)
• Full Moon - when the moon's disk is light because
  the Earth is between the sun and the moon
• Gibbous Moon - when we can see roughly
  three-quarters of the moon's disk
• Quarter - when we can see one half of the moon's
  disk (this is one-quarter of the entire moon's
  surface)
• New Moon - when the moon's disk is dark (and
  invisible to us) because the moon is between the
  sun and the Earth
• Waning Moon - when the moon seems to be getting
  smaller, going from full to gibbous to half to
  crescent to new
• Waxing Moon - when the moon seems to be getting
  bigger, going from new to crescent to half to
  gibbous to full

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Animation of motion
6
Moon phases Data

• The Moon appears to go through phases. The period
  of this cycle is approximately 29.5 Earth days.)
• The moon takes about 27.3 days (about a month) to
  revolve around Earth, traveling at an average
  distance of about 384,000 kilometers.
• Its diameter of the moon is about a quarter that
  of Earth's.
• The Moon rises in the east and sets in the west
  daily, but its position in the sky moves EASTWARD
  by about 13 degrees per day.
• (360 degrees divided by 27.32 days 13.177
  degrees per day)

7
Orbit Angle changes
Sidereal Month The daily motion of this point
provides a measure of the rotation of the Earth
with respect to the stars, rather than the Sun.
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Moon Phase Views
New Moon - The Moon's unilluminated side is
facing the Earth.
Waxing Crescent - The Moon appears to be partly
but less than one-half illuminated by direct
sunlight



First Quarter - One-half of the Moon appears to
be illuminated by direct sunlight
Waxing Gibbous - The Moon appears to be more than
one-half but not fully illuminated by direct
sunlight
9
Moon Phase Views continued
Full Moon - The Moon's illuminated side is facing
the Earth
Waning Gibbous - The Moon appears to be more than
one-half but not fully illuminated by direct
sunlight.
Last Quarter - One-half of the Moon appears to be
illuminated by direct sunlight
Waning Crescent - The Moon appears to be partly
but less than one-half illuminated by direct
sunlight
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Eclipse of the Moon
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Images Of a Lunar Eclipse
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Summary

• The phases of The moon is caused by the orbit of
  the Moon around the Earth
• The Sun illuminates the Moon at different angles
  during the month
• The names of the Moons phases are based on the
  amount of illumination and the process of
  increasing size (waxing) or decreasing size
  (waning)
• The orbit is divided into 4 quarters.