1. Craters of the Moon Read Ch. 4 of the text, sections 4.1 through 4.6

2. William Herschel thought he saw 3 volcanos on the moon in 1787

3. Arguments circa 1920 in favor of a volcanic origin Few impact craters known on Earth –Meteor crater (Barringer crater) in Arizona

4. Moon craters are mainly round If impacts came in from all directions, wouldn’t we have more elongated craters?

5. Small craters overlap large craters, rather than vice versa

6. Some thought they saw craters in the central mountain peaks

7. Impact origin Championed by G.K. Gilbert and others in the 19 th century, but didn’t really take hold until the middle of the 20th

8. A Michigan native, Ralph Baldwin, helped turn the argument in favor of impacts

9. Baldwin compared craters produced by explosions on the earth with the craters of the moon He found that they followed the same trend of diameter versus depth Impacts produce a generally round explosive crater regardless of direction of impact

10. Apollo Landings Lunar rocks mainly breccias – rocks shattered by impacts

11. Crater Types

12. Simple craters are relatively small

13. Complex craters are bigger

14. Copernicus

15. If Copernicus were 9-inches across, its depth would be only 1/3 of an inch!

16. King Crater

17. Basins: the Largest impact features Orientale basin

18. Mare Imbrium

21. Mare Humorum