Moon and its motions
The Earth’s Moon Surface features Maria Craters
Movements of the Moon Lunar rotation and revolution Go to ESRT page 15 Period of rotation = ______________ Period of revolution = ______________ https://www.youtube.com/watch?v=6jUpX7J7ySo&feature=em-subs_digest Why do we always see the same side of the moon? 27.3 days 27.3 days Period of rotation = period of revolution
To an observer on earth the moon rises and sets 50 min To an observer on earth the moon rises and sets 50 min. later each night. Why is there a difference in period of revolution and the moon cycle?
Notice in picture 1, the moon is directly between the Earth and the Sun. But by position 5, even though the moon is directly below the Earth, it is no longer between the Earth and Sun. The moon must travel 2.2 more days to be exactly between the Earth and Sun (new moon).
Time for moon to complete all phases in its cycle? 29 - 30 days
Apogee – farthest point in an orbit Perigee – closet point in an orbit
Moon’s Revolution Moon’s orbit around the earth is This causes the moon’s diameter/size to change in a elliptical, with Earth at one of the foci cyclic manner
Moon looks bigger at perigee, especially when it first rises
Which is at perigee? Which is at apogee?
Phases of the Moon - Reasons Caused by We see the illuminated part of the moon’s surface CYCLIC Moon’s revolution around Earth
Phases of the Moon
Only the half facing the sun will be illuminated. Color the illuminated and dark half of each moon.
Next, draw the moon’s orbit around the earth
Purple line is the orbit of the moon around the Earth
What does the moon look like from Earth at Position #1? NEW MOON
What does the moon look like from Earth at Position #2? WAXING CRESCENT
What does the moon look like from Earth at Position #3? FIRST QUARTER
What does the moon look like from Earth at Position #4? WAXING GIBBOUS
What does the moon look like from Earth at Position #5? FULL MOON
What does the moon look like from Earth at Position #6? WANING GIBBOUS
What does the moon look like from Earth at Position #7? THIRD QUARTER
What does the moon look like from Earth at Position #8? WANING CRESCENT
Waxing and Waning Waxing – increase of moon’s visible light - new moon to full moon Waning – decrease of moon’s visible light - full moon to new moon Time is takes to go from full moon to the next full moon? ____________ 29-30 days
http://apod.nasa.gov/apod/ap991108.html https://www.youtube.com/watch?v=79M2lSVZiY4 (mr lee rap)