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By Rosie Levine and Madeline Buckley (Orange)

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Moons Orbital Period

  • The time it takes the moon to complete one orbit around the earth

  • 27.3 days (about a month)
  • moves 13 degrees per day
  • moves 1/2 degrees per hour
  • On a different plane of orbit then the Earth and the Sun- about 5 degrees off.
  • perigee is when the moon is as close to Earth as it gets in its orbital period
  • apogee is when the moon is as far away from Earth as it gets in its orbital period.
  • the moon has an elliptical orbit- not quite a circle causes the phases of the moon.
  • The moon's place of orbit around Earth is tilted 5 degrees from Earth's place of orbit around the sun

Moons Rotational Period

  • The time it takes the moon to rotate fully around on it's axis once

  • 27.3 days (about a month)
  • the moon's orbital and rotational periods are the same- ~one month = one moon orbit around earth and one moon rotation
  • the same orbital and rotational periods also results in people on Earth being only able to see one side of the moon


1. Tides

  • direct and indirect tides caused by moon's gravitational pull on the water and land of Earth
  • Since the moon is moving 13 degrees each day, the Earth must rotate an extra 13 degrees in order to be in the same place this results in tides occurring 50 minutes later each day than the previous and moon rise/set occurring 50 minutes later.

2. Phases of the moon

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  • The Sun lights up the half of the moon it is facing. This half changes based on where the moon is in it's orbit.
  • 1/2 the moon is always lit up, but on Earth, we can only see the part of the moon that is facing us.
  • Although the moon is always the same we can only see the part that is illuminated bu the sun -- these phases are called:
    • New---When there appears there is no moon in the sky
    • Waning --When the sun is tilted so the moon appears to be illuminated on the Right
    • Full--When the Moon appears to be fully illuminated
    • Waxing--When the moon appears to be illuminated on the Left
  • To see the moons current phase Click here

*For help...look at the lab we did with the phases of the moon wheel!

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Sped up version of one lunar month

3. Eclipses

  • Lunar Eclipse- when the Earth's umbra (shadow) touches the moon's surface. Common
  • Without moon's 5 degree difference in orbital plane from Earth- lunar eclipses occur every full moon.
  • With 5 degree difference- the moon usually above or below Earth's umbra
  • Solar Eclipse- when the moon's umbra (shadow) touches the Earth's surface. Rare
  • Occurs so rarely because it must must be new moon and and in the right place in orbit.

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Eclipses Diagram

4. Moon rise and set

  • Over the course of on day the Moon will rise in the east and set in the west (from view on Earth).
  • The Moon progresses through a 360 degree orbit at a faster rate than the Earth goes through it's own orbit
  • Because of this each night the Moon will rise and set about 50 minutes later

FUN FACTS-- about the moon's orbit and rotation!

  • the moon follows the ecliptic- the apparent path of the constellations, etc. across the sky.
  • the moon is the only satellite that has an orbital period that lasts as long as it's rotational period
  • The Moon is know as earth's only natural satellite
  • The Moon appears to be lower in the sky in the summer because of its tilt and location that changes because of its orbit and rotation
  • And Vice Versa in the Winter!

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Moons Orbital Effects

REVIEW QUESTIONS!-->taken from Mrs. Fretz's original moon test

1. Earths moon is also known as Earth's only _ _ _ _ _ _ _ satellite.

2. The Moon's orbit around Earth is similar to Earth's orbit around the sun in that both orbits are_ _ _ _ _ _ _

3. When the distance between Earth and the Moon is shortest, the Moon is said to be at _ _ _ _ _.

4. When the distance between Earth ad the Moon is longest, the Moon is said to be at _ _ _ _ _ _ _ _

5. Because the Moon's orbital period and rotational period are exactly the same, we _ _ _ _ _ _ _ .

6. From night to night the Moon with rise and set about _ _ _ _ _ _ _ _ _ _ .

7. This phenomenon is a result of_ _ _ _ _ _ _ _ _.

8. The Moon's plane of orbit around Earth is tilted _ _ _ _ _ _ _ _degrees from Earth's plane of orbit around the sun.

9. It takes longer from the Moon to complete one cycle of its phases than it does for the Moon to complete one orbit because_ _ _ _ _ _.

10. When the moon is waxing it appears to be illuminated on the _ _ _ _ _ side.
How about when the moon is waning?

Moon's Orbit around the Earth


  • Check out Chapter 24 (pages 433-456) in your Earth Science Textbook
  • Look back on your class notes, Moon Labs (gaging the moon tide etc.), and test from our moon unit
  • Do the Chapter 24 review section on pages 454-455 in your Earth Science Textbook
  • Explore the other wiki on the moon created by your classmates!
  • Some wikis to see: Moon and Tides, Moon Phases, Moon Basics, and Tides.
  • For answers to the review questions---check out your moon test--or find them in this Wiki
  • Info taken from: Moon Test, Class Notes, and Earth Science Textbook.