1. Chapter 28 Minor Bodies of the Solar System The Moon

2. Lunar Facts Earth’s only natural satellite The Moon orbits the Earth at a distance of about 384,000 km (240,000 miles) The Moon is about 3,468 km in diameter- about ¼ the size of Earth. The Moon orbits the Earth at a 5 o angle with respect to the Earth’s orbit around the Sun. Earth’s orbital plane Moon’s orbital plane

3. Space Exploration 1957- the Soviet Union launches, Sputnik, the first artificial satellite 1958- the U.S. launched its first, Explorer 1 Thousands now orbit the Earth

4. Lunar Missions July 20, 1969 Neil Armstrong became the first man on the Moon Between 1969 and 1972, the U.S. accomplished six Apollo missions 12 Americans have walked on the moon

5. Apollo 11 Mission First Lunar Landing Footage

7. The Lunar Surface No atmosphere Extreme temperatures –Daytime = 130  C (265°F) –Nighttime = - 190  C (-310  F) 1/6 Earth’s gravity

8. Mountains up to 7500 m (25,000 ft) tall Ridges- long, narrow elevations of rock that crisscross the moon’s surface. Highlands The Lunar Surface Highlands

9. The Lunar Surface Maria Dark areas made chiefly of basalt Galileo named them for there “sea”-like appearance Formed 3-4 billion years ago by magma resulting from massive impacts or radioactive decay Mare

10. Lunar Features Rilles Long, deep ancient lava channels leftover from the formation of maria

11. Lunar Features Craters Most formed by meteorite impact on the Moon Young craters characterized by bright streaks, called rays

12. Lunar Features Regolith Fine layer of dust and rock that covers the moon’s surface

13. Lunar Features Rocks Similar to igneous rocks found in Earth’s crust Breccia- contain fragments of other rocks fused together

14. The Interior of the Moon Crust: 60-100 km thick –Thickest on far side Mantle: 1,000 km thick –Possibly made of Si, Mg and Fe Core: radius less than 700 km –Non-uniform (liquid and solid)

15. Comparison of the Near and Far Sides

16. So where did the moon come from?

17. The Spin or Fission Theory

18. The Capture Theory

19. Failed Planet Theory

20. The Giant Impact Theory

21. Giant Impact Theory Formed 4-5 billion years ago Caused by impact of Mars- sized “planetesimal” on Earth Debris melted together to form the Moon

22. Movements of the Moon Revolution: the Moon orbits the Earth every 27.3 days Rotation – Moon turns on its axis every 27.3 days We always see the same side of the Moon because its period of rotation equals its revolution! This is called synchronous rotation.

24. Earth Moon Plane of earth’s orbit Plane of lunar orbit Orbital Planes of the Earth and Moon

25. The Earth-Moon System Apogee- point at which the Moon is farthest from Earth Perigee- point at which the Moon is closest to Earth

26. Illumination of the Moon Moonlight is reflected sunlight Half the moon’s surface is ALWAYS reflecting light

27. Illumination of the Moon Waxing- occurs when the size of the lighted part of the Moon is increasing Waning- occurs when the size of the lighted part of the Moon is decreasing

28. Phases of the Moon From Earth we see different amounts of the Moon’s lit surface The amount we can see is called a “phase”

29. starchild.gsfc.nasa.gov/docs/StarChild/questions/phases.html

30. Phases by Day

31. Phases PHASE APPROXIMATE DURATION NEW1 DAY WAXING CRESCENT SEVERAL DAYS 1 ST QUARTER1 DAY WAXING GIBBOUSSEVERAL DAYS FULL1 DAY WANING GIBBOUSSEVERAL DAYS LAST QUARTER1 Day WANING CRESCENT SEVERAL DAYS

32. Moon Phases Video

34. Eclipses Eclipses are caused when one celestial body passes through the shadow of another The Sun and Moon occasionally line up with the Earth so that an eclipse occurs A solar eclipse occurs when the Moon passes between the Earth and the Sun and the shadow of the Moon falls on the Earth A lunar eclipse occurs when the Earth passes between the Sun and the Moon and the shadow of the Earth falls on the Moon

35. Solar Eclipses When the Moon’s shadow covers part of the Earth Only happens at New Moon Observers in the “umbra” see a total eclipse (corona is visible) Those in the “penumbra” see a partial eclipse Save the date! The next U.S. total solar eclipse will occur 21 August 2017!

36. Total Solar Eclipse

37. When the Earth’s shadow covers the Moon A total lunar eclipse occurs when the entire Moon passes into the Earth’s umbra A partial lunar eclipse occurs when only part of the Moon passes into the Earth’s umbra A penumbral eclipse occurs when the entire Moon passes into the Earth’s penumbra Lunar Eclipses

38. Even during a total lunar eclipse, sunlight is bent around Earth through the atmosphere The Moon is visible and appears to have a reddish tint Save the date! The next U.S. total lunar eclipse will occur 21 December 2010!

39. The Tides The Moon’s gravity tugs on the Earth. –It pulls the most on the part of Earth closest and least on the farthest causing tidal bulges High tide – –Side facing Moon and side away from Moon Low tide – –On sides of Earth

40. Tidal Patterns

41. Time for reflection! Think back to your lunar modeling activity… Have your preconceptions changed? How?

42. THE END