1. Earth’s Moon
1.1.2 a Describe daily changes due to rotation, seasonal changes due to the tilt and revolution of the Earth, and tidal impact due to the gravitational interaction between the Earth and moon.
1.1.2b Develop a cause and effect model for the shape of the Earth explaining why the circumference around the equator is larger than that around the poles.

2. The Moon What do we know already? * When have you seen the moon?
* What does it look like?
* Have you ever seen its craters?
* Do the patterns of the craters ever change?
The moon revolves around the earth with a period of about 29 2

3. Origin and Properties of the Moon
Earth’s Moon
Origin and Properties of the Moon
Scientists think the moon formed after a large object, about the size of a planet, hit Earth.
1. Earth is hit off-center by a planet-sized object.
2. The impact heats and deforms both bodies. Some rocky debris remains in orbit around Earth.
3. The debris ring, made of rock from the outer layer of both objects, gradually coalesces, forming the moon.

4. Much of the material broken away from the earth goes into orbit.
The moon reassembles in this orbit - it takes about a month of violent collisions. 
Earth is speeded up in rotation as a result of the collision.
This theory is consistent with:
1.) composition of lunar rocks, which is similar to the composition of the crust of the earth;
2.) evidence that the moon had a molten surface for 200 million years; and
3.) the lack of magnetic field for the moon, which together with its low density implies it has very little iron in its core.
Impact theory

5. The Moon’s Motions Earth’s Moon
The moon’s orbit is tilted 5 degrees relative to the plane of Earth’s orbit. The moon’s movement around Earth causes it to rise later each day and to go through phases.
Light from the Sun
Waning Crescent
Waxing Crescent
New Moon
Full Moon
Waning Gibbous
Waxing Gibbous
Last Quarter
First Quarter
Phases of the Moon

6. Lunar Phases Sunlight illuminates half of the Moon
it’s a ball and the Sun is shining on it from one direction
This causes the “phases” of the Moon
Waning Moon – decreasing from full to new moon
Waxing Moon – increasing from new to full moon

7. Lunar Phases (cont) New Moon Full Moon
Waxing Crescent Moon
Waxing Half Moon
Waxing Gibbous Moon
Full Moon
Waning Gibbous Moon
Waning Half Moon
Waning Crescent Moon …
New Moon
The Moon is on the same part of the sky as the Sun and rises and sets with the Sun
Full Moon
The Moon is in the opposite side of the sky as the Sun and rises when the Sun sets and sets when the Sun rises

8. The Phase of the Moon
The phase of the Moon depends on the relative position between the Sun, the Earth, and the Moon…

9. The time the Moon rises and sets is correlated to its phase
Moonrise/Moonset
The time the Moon rises and sets is correlated to its phase
Phase of the Moon
Rise
Zenith
Set
New Moon
6 am
6 pm
Waxing Half Moon
Full Moon
Waning Half Moon
Noon
Noon
Noon
Midnight
Midnight
Midnight
6 pm 9

10. Why do we Always See the Same Side of the Moon?
The rotation period of the Moon with respect to the universe is exactly the same as the rotation period of the Moon around the Earth.
Is this a coincidence?
No! ⇒ It’s due to Tidal Locking

11. Tidal Locking
A tidally locked body takes just as long to rotate around its own axis as it does to revolve around its partner. This synchronous rotation causes one hemisphere constantly to face the partner body.
The Moons orbital period is 27.3 days. It also rotates once on its axis in 27.3 days (synchronous rotation) resulting in Tidal Locking.

12. “Dark Side” of the Moon The Moon doesn’t have a “dark side”
Everywhere on the Moon, the Sun rises and sets once per month
It has a side which faces away from us
During a New Moon, the far side is completely illuminated

13. The Moon’s Motions
A lunar eclipse occurs when Earth passes between the sun and the moon, and the moon is within Earth’s shadow.
Sun
Earth
Penumbra
Moon
Umbra
lunar eclipse
A solar eclipse occurs when the moon passes between the sun and Earth, and the moon’s shadow falls on Earth.
Total Solar Eclipse
Sun
Earth
Moon
solar eclipse 13

15. Solar Eclipse Forecast
Solar eclipses from 2004 to 2030
Knowing the orbit of the Earth and the Moon, we can now calculate the time and path of solar eclipses with great accuracy.