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Mav Mark 10/11/12 What bit of information was Newton's Law of Universal Gravitation lacking?

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Mav Mark 10/11/12. What bit of information was Newton's Law of Universal Gravitation lacking?. Mav Mark 10/12/11. How many forces are acting on a baseball that is thrown by a pitcher?. Phases, Eclipses, and Tides. Notes. Lunar Motions. Our moon’s name = Luna - PowerPoint PPT Presentation

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Page 1: Mav Mark 10/11/12

Mav Mark10/11/12

What bit of information was Newton's Law of Universal Gravitation lacking?

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Mav Mark10/12/11

How many forces are acting on a baseball that is thrown by a pitcher?

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Phases, Eclipses, and Tides

Notes

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Lunar Motions •Our moon’s name = Luna

•The changing relative positions of the moon, Earth, and sun cause the phases of the moon, eclipses, and tides.

•Luna revolves around the Earth. It takes the moon about 27.3 days to revolve around Earth once.

•As Luna and Earth move, their positions change in relation to each other. Their positions also change in relation to the sun.

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Lunar Motion

•Our moon it tidally locked with Earth.

•This means that the moon’s day is the same as its year. It takes one month to rotate on its axis and one month to complete one revolution around Earth.

•Because of this, only one side of Luna faces Earth. The other side is ALWAYS facing away from Earth.

•There is no such thing as the “dark side” of the moon, but there is a “far side.”

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Lunar Phases

• The phase of the moon you see depends on how much of the sunlit side of the moon faces Earth.

• The moon does not give off its own light. The moon reflects light from the sun.

•Question: How much of the moon is ALWAYS lit up by the light from the sun?

•Question 2: How much of every object in this solar system is ALWAYS lit up by the sun?

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Phases of the Moon•The moon appears to have

different shapes at different times. These different shapes of the moon that you see are called phases.

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Lunar Phases

•As the moon revolves around Earth, you see the moon from different angles. You cannot see all of the half of the moon that is lit by the sun.

•http://upload.wikimedia.org/wikipedia/commons/c/c0/Lunar_libration_with_phase2.gif

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Lunar Phases

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Eclipses•Eclipse - to cover up

•When Luna’s shadow hits Earth or Earth’s shadow hits Luna, an eclipse occurs. A solar eclipse occurs when the moon passes directly between Earth and Sol, blocking sunlight from Earth.

•An eclipse is when an object in space comes between the sun and another object.

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Eclipses

•Sometimes the moon moves between Earth and Sol. The moon blocks sunlight from reaching Earth (this means the moon is casting its shadow onto the surface of Earth). A solar eclipse occurs when an NEW MOON blocks your view of the sun.

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Eclipses

•A lunar eclipse occurs when Earth is between Luna and Sol.

•In a lunar eclipse, Earth’s shadow hits the moon.

•A lunar eclipse occurs when there is a FULL MOON.

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Eclipses

•So why is there not a solar and lunar eclipse each time we have a NEW MOON and FULL MOON?

•The moon does not lie in a straight line between Earth and Sol. It is tilted about 5° from the ecliptic. Because of this tilt, eclipses are much rarer than expected.

•http://eclipse.gsfc.nasa.gov/eclipse.html

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Tides

• Tides are caused mainly by differences in how much Luna’s gravity pulls on different parts of Earth.

• Tides are the regular rise and fall of ocean water. The ocean waters rise for about 6 hours a day, and fall for about 6 hours a day. Therefore there are two high tides and two low tides every 24 hours.

• Luna’s gravity causes tides. The force of the moon’s gravity causes ocean water on Earth to move higher in some places and lower in other places.

• Sol’s gravity also pulls on Earth’s ocean waters.

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Tides•During a NEW MOON, Sol, Earth, and Luna

are lined up in a straight line. The combined forces of the sun and the moon cause spring tides. A spring tide is the highest possible high tide.

•Sometimes the sun, moon, and Earth form a right angle (90°). This arrangement occur at the FIRST and THIRD QUARTER moons, and produces a neap tide. A neap tide is the lowest possible high tide.

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