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The Moon. Aim: Does the moon actually change shape?. Why does the moon have so many craters?. Earth was hit by the impactors too but we have weather, water, erosion, plants, plate tectonics that changes our surface.
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The Moon Aim: Does the moon actually change shape?
Why does the moon have so many craters? • Earth was hit by the impactors too but we have weather, water, erosion, plants, plate tectonics that changes our surface. • The moon does not have an atmosphere or water so its surface stays the same.
Lunar Motions • The apparent daily motion of the moon is from east to west. • As the moon makes one revolutionaround the Earth, it also makes one rotationon its axis. • This is why we always see the same sideof the moon (the same side of the moon is always facing the Earth)
Moon Terms • Sidereal Month– It takes the moon 27 1/3 daysto complete one revolution (orbit) around the Earth. • Synodic Month– The time required for the moon to complete a cycle of phases is 29 ½ days.
INTERESTING FACT: • The word month comes from moonth since people used celestial observations for time.
Our closest neighbor in space… • What have you noticed about the moon over a monthly cycle? The moon seems to change its shape!
It’s a Phase they go through • The amount of lighted sidewe can see from earth varies as the moon revolvesaround us during one month in a cyclicpattern.
The moon is always half lit and half dark – every round object in space is! • From Earth, we only see a portion of the lit side
Moon’s Rotation = Moon Revolution • Rotation Period = 27.3 days • Revolution Period = 27.3 days • Moon shows the same “face” to the Earth • Velocity = 360/27.3 days = 13 per day
Moon’s Positions (or “Phases”) • New moon– the entire lit portion of the moon is facing AWAY from the earth; no light visible • Full moon– the entire lit portion of the moon is facing TOWARD the earth
Waxing: the RIGHTportion of the moon seems to GROW. Waning: the LEFT portion of the moon seems to SHRINK
Waxing vs. Waning • Waxing phases are when the amount of lighted side we see increases each night • First light on right – from new to full • Waning phases are when the amount of lighted side we see decreases each night • Last light left – from full to new
Crescent vs. Gibbous • Crescent Moons– phases where you can see lessthan half of the bright side • Gibbous Moons– phases where you can see more than half of the bright side
Phases of the Moon The general locations and orientations for the phases of the moon. (7) Third Quarter (6) Waning Gibbous (8) Waning Crescent Sunlight Earth (1) New Moon (5) Full Moon Earth spins on its axis in the same direction as the moon’s orbit. (2) Waxing Crescent (4) Waxing Gibbous (3) First Quarter
What part of the moon will we see? Sunlight Earth (1) New Moon How much of the moon’s face does the person see? NEW MOON Wherever the person looks all they see is shadowed moon. What time of day is it for the observer? Noon!!
Sunlight Earth (2) Waxing Crescent More phases How much of the moon’s face does the person see? WAXING CRESCENT When you look up you see only a small crescent brightly lit. (Right Side) What time of day is it for the observer? 3PM!!
The next phase… Sunlight Earth (3) First Quarter How much of the moon’s face does the person see? FIRST QUARTER When you look up you see one half of the front face of the Moon brightly lit. (Right side) What time of day is it for the observer? Sunset - 6PM!!
Sunlight Earth (4) Waxing Gibbous And the next phase… How much of the moon’s face does the person see? WAXING GIBBOUS When you look up you see only a small crescent, darkly shadowed, on the left. What time of day is it for the observer? 9PM!!
Sunlight Earth (5) Full Moon It’s becoming clear… How much of the moon’s face does the person see? FULL MOON When you look up you see the entire face of the Moon brightly lit. What time of day is it for the observer? Midnight-12AM!!
(6) Waning Gibbous Sunlight Earth Hey, what’s happening… How much of the moon’s face does the person see? WANING GIBBOUS When you look up you see only a small crescent, darkly shadowed, on the right. What time of day is it for the observer? 3AM!!
(7) Third Quarter Sunlight Earth I’m melting…I mean shrinking… How much of the moon’s face does the person see? THIRD QUARTER When you look up you see one half of the front face of the Moon brightly lit. (Left side) What time of day is it for the observer? Sunrise - 6AM!!
(8) Waning Crescent Sunlight Earth Soon I’ll be gone… How much of the moon’s face does the person see? WANING CRESCENT When you look up you see only a small crescent brightly lit. (Left Side) What time of day is it for the observer? 9AM!!
What types of Eclipses are there? • Solar Eclipses – the sun is blocked from view • The moon gets between sun and earth • The sun’s light is completely blocked by the moon • Can only happen during new moon phase • but not every time, because moon’sorbit is tilted
The next total solar eclipse in New York will be 8/21/2017 • Mark your calendars now!!!
Lunar Eclipses – the moon is blocked from view • Occurs when full moon passes into Earth’s shadow and is temporarily blocked from view.
Sunlight is bent around Earth through our atmosphere. • Mainly red light reaches the moon, so the totally eclipsed moon appears to have a reddish color.
How often do we have eclipses? • About 7 eclipses during every year • The orbit of the moon is not in the same plane as the orbit of Earth around the sun • The moon’s orbit is tilted 5° to Earth’s orbit • This is why we do not have total eclipses so frequently
Moon’s Effect on Tides • Gravitational attraction pulls on Earth’s water creating a cycle of high and low tides
Spring Tides • During the new moon and the full moon • Earth, the sun, and the moon are aligned • The combined gravitational pull of the sun and the moon results in higher high tides and lower low tides • The daily tidal range is greatest during the new and full moon periods
Neap Tides • During the first-quarter moon and third-quarter moon • Earth, the sun, and the moon are at right angles • The combined gravitational pull of the sun and the moon work against each other • The daily tidal range is small during this period
Two high tides and Two low tides • Every day cycle because earth rotates into and out of high water
Cycle of tides • Spring Tide • NOT the Season !!! • Highest high tide when sun-earth-moon aligned • During full and new moon positions only • Neap Tide • Lowest high tide when sun-earth-moon at right angles • During quarter phases only