1. Phobos, moon of Mars It’s a tough neighbourhood out there….

2. Mercury

3. Moon

4. Can see pathways of ejecta…

5. Moon up close from Apollo where would you land?

6. Mars Mercury Venus Earth’s Moon (S. Pole)

7. Earth looks a little different!

8. But there are known impact sites Why in these locations?

9. Mistastan Lake, New Foundland, Canada 28 Km 38,000 years All diameters are for the crater (not the impactor)

10. Barringer Meteor Crater, AZ 1.18 km 49,000 years

11. Wolf Creek, Australia 0.875 Km 300,000 years

12. Bosumtwi, Nigeria 10.5 Km 1.3 Million years

13. Roter, South Africa 2.5 km 5 Million years

14. Karakul, Tadjikistan 45 Km < 10 Ma

15. Chicxulub, Mex 170 Km 65 Ma

16. Clearwater Lakes, Sask. 32 km/22km 290 Million years Deep Bay, Sask. 13 km 100 Million years

17. Gosses Bluss, Australia 22 km 142.5 Million years

18. Aorounga, Chad 17 km 200 Million years

19. Manicougan Lake, Quebec 100 km 212 Million years

20. Formation of the moon?

21. Radar Image of NEO 1999JM8 Missed Earth by 5 million km in 1990, 6 million km in 1999 Average diameter 3.5 km

22. 80 million trees knocked down over 2,150 square kilometres (830 square miles Tunguska Event, 1908, Russia

23. Tunguska Event 1908 Equivalent to a 100 MT Nuclear Bomb Blast

24. Question If cratering rate on Earth is same as our Moon, why are their so few craters preserved?

26. Calculated from counting moon craters, and dating From Apollo samples

27. Typical menacing rocky asteroid (comets also have ice in them, and tails)

28. How often do these things happen?

30. What is wrong here?

32. Apollo 14 site spherules (~ 0.2 mm diameter) Argon40/Argon39 dates (accuracy ~ +/- 200 MY) Glass spherules created at time of impact

33. Knock something out of the Oort Cloud, and we might be in trouble…

34. Apollo 14 site spherules (~ 200 micro-meters diameter) Argon40/Argon39 dates (accuracy ~ +/- 200 MY)  26 Ma periodicity  Claim is that extinctions happen with that periodicity?...

35. Is nemesis out there?

36. 1 BY averaging bins Black and opaque spherules only (the ones most definitely related to impacts) A couple of slides back it looked light an upsurge in impacts recently, But it depends on how you process the data…

38. Question: If cratering rate on Earth is same as our Moon, why are their so few craters preserved? Answer: Erosion