1. Sponge - What are two differences in lunar soil and soil on Earth?

2. Lunar Interior - The low average density (3 g/cm 3 ) implies that the entire Moon is low in iron and other heavy metals.

3. The absence of a magnetic field could be the result of the Moon’s slow rotation, or the absence of a liquid core, or both.

4. A 200 km radius core, a 500 km thick semi-solid rock aesthenosphere, a 1000 km thick mantle, and a 60 to 150 km thick crust is probable.

5. The Moon’s crust is thicker than Earth’s. The side near the Earth is about 65 km thick, the far side is about 150 km thick.

7. The difference in crust thickness explains why there are no maria on the far side, it was a shorter distance to the surface on the near side.

8. This difference in crust thickness is probably due to the Earth’s gravity “pulling” the denser mantle closer to the Earth.

9. Origin of the Moon The Sister, or Co-formation, theory - the Moon formed as a separate object from the same material.

10. Problem: The Moon differs in density and composition from the Earth.

11. The capture theory- The Moon formed far from Earth and was later captured by it.

12. Problem: Since the Moon’s mass is large compared to the Earth’s, this capture probably couldn’t happen.

13. The daughter, or fission theory - the Moon was torn out of the Earth itself as a result of the young Earth’s rapid spin, or due to tidal effects from the Sun.

14. Problem: If the Earth spun this fast, it would probably have torn the Earth completely apart. Plus, the Moon would not be ejected into a stable orbit in this case.

15. The impact theory – A glancing collision by a large Mars-sized object with a young molten Earth. The dislodged matter from our Earth then assembled into the Moon.

16. This is the only theory that fits all of the evidence.

17. Lunar Exploration Luna 1 (Russian) passed the Moon on Jan. 4, 1959. Luna 2 crash landed in Sept. and Luna 3 returned pictures of the far side in Oct. of the same year.

18. Luna 9 soft-landed in Feb. 1969. Several Luna missions, including Luna 24 (the last), returned with lunar surface material.

19. Lunokhod

20. Lunokhod was a robot that explored the surface of the moon.

21. The Ranger missions (USA) didn’t hit the Moon until Ranger 7 on June 28, 1964. The US also sent five Lunar Orbiters (1966-67) and seven Surveyor missions (1966-68) which soft-landed.

22. On July 20, 1969 Neil Armstrong became the first man to set foot on the Moon. On December 14, 1972 Harrison Schmidt was the last. This was part of the Apollo program.

28. Buzz Aldrin

31. In all, 12 men have walked on the Moon over six missions. The later missions brought a “lunar rover” with them.

37. Apollo 17 lunar blast-off

40. Crater (center of image) formed by impact of the Apollo 14 Saturn IVB booster. The booster was intentionally impacted into the lunar surface on February 4, 1971 to serve as an energy source to probe the interior structure of the Moon using seismometers placed on the surface by Apollo astronauts [NASA/GSFC/Arizona State University].

41. 382 kg of Moon material was returned to Earth by the Apollo missions.

42. Each Apollo lander left an experiment package called ALSEP (Apollo lunar surface experiments package).

43. It monitored solar wind, measured interior heat flow, and recorded seismic activity. The ALSEP’s were turned off in 1978 to save money.

44. Green cheese moon (note the expiration date)

45. Earth and Moon taken by Apollo 8