1. The Earth-Moon System

2. Spheres
A sphere can be defined as a three dimensional figure like a ball – The Sun, all planets and moons are spheres

3. Ellipse An ellipse – very similar to a circle…a little oval shaped
Each planet orbits the sun in an elliptical path
During certain times of the year…the Earth is closer to the sun than other times of the year.
Ellipse Animation

4. Rotation
The planets, the Sun, moons, and the Earth all rotate around their axis, or center.
All planets, except Venus and Uranus, rotate counter-clockwise

5. Revolution
The orbit of one body around another…the Earth makes one revolution of the Sun in 365 days.
The Moon makes one revolution of the Earth in 28 days
All planets orbit the Sun in a counter-clockwise direction

6. Earth Moon Relationship
Earth’s only natural satellite.
Size scale – If the Earth was a basketball with a 12” diameter (1 foot) then the moon would be a 3” tennis ball.
Distance scale – using the same scale as above – the moon would be 30 feet away.
Correct size scale
Incorrect distance scale

7. Other Moons of Importance
Four of Jupiter’s many moons
Called the Galilean moons (Galileo first found them)
Io has a special characteristic…

8. Jupiter’s Io
Only known moon to be volcanically active in the solar system

9. Saturn’s Many Moons
Titan is heavily studied right now – has similarities to Earth

10. Earth’s Moon - Revolution & Rotation
The moon orbits the Earth, roughly once every 28 days. (once a month)
The moon spins on its axis once every 28 days. (once a month)
Therefore, the rotation and the revolution are the same rate.
Most moons in the solar system have the same tendency – phenomenon called tidal lock

11. The Dark Side of the Moon
There actually is a “dark” side of the moon – at least as seen from Earth
WE ONLY SEE ONE SIDE OF THE MOON BECAUSE IT ROTATES AND REVOLVES AT THE SAME RATE

12. Lunar Craters & Maria
Mare – Greek for sea
- Seas of lava
The moon’s surface is covered with craters and maria.
Impact craters – from the bombardment of meteors.
Craters more visible than craters on Earth - no erosion or vegetative cover on the moon
Maria - flat regions made by ancient lava flows. (no volcanic activity on the moon in millions of years)
Crater abundance

13. Apollo Mission Landing Sites

14. Phases of the Moon
Click below for video clip

15. Phases of the Moon

16. Phases of the Moon
Moon phases are caused by the moon’s orbit around the Earth and its reflection of the sun
Waxing indicates the portion of the moon’s surface we see is getting larger
Waning indicates the portions of the moon’s surface we see is getting smaller

17. Phases of the Moon

18. Solar Eclipses
A solar eclipse occurs when the Moon passes between the Sun and the Earth.
Occurs during which moon phase?
New moon
During a solar eclipse the normally transparent corona (outer layer of the sun) can be seen.

19. Solar Eclipses

20. - Direct shadow – very small area
- Secondary shadow – much larger area

21. Solar Eclipse

23. Lunar Eclipses Occurs during which moon phase? Full
Occurs when the Moon passes into the shadow cast by the Earth
Occurs during which moon phase?
Full

24. Lunar Eclipse

26. Reason for the seasons What causes Winter, Spring, Summer & Fall?

27. What does this graph tell you?

28. What does this graph tell you?
Earth’s path around the sun is not a perfect circle
The path is in the shape of an ellipse
Earth is closer to the sun in January (winter in the northern hemisphere)
Distance to the sun has NOTHING to do with Earth’s seasons

29. What causes Earth’s Seasons?
Click below for video clip

30. The Earth’s Tilt The Earth is tilted on its axis 23.5 degrees.
The Earth’s tilt is the reason why we experience different seasons on Earth.
As the Earth travels around the sun throughout the year, different parts of the Earth are tilted toward the direct rays of the sun.

31. Equinox and Solstice
Vernal (spring) or autumnal (fall) equinox = equal day and equal night.
Winter solstice = shortest day of the year in the NH
Summer solstice = longest day of the year in the NH