1. Comets, Meteors, and Asteroids

2. Structure of a Comet
To Sun
Ion
Tail
Dust
Tail
Coma

3. Comet Structure
 Nucleus
10 km “Dirty Snowball”
 Coma
Cloud of evaporated ices and ions
may be 100,000 km in diameter
 Tail
Always points away from Sun
Solar Wind and Radiation Pressure

4. The Oort Cloud
 In 1950 Jan Oort noticed that
no comet has been observed with an orbit that
indicates that it came from interstellar space,
there is a strong tendency for aphelia of long period
comet orbits to lie at a distance of about 50,000 AU,
and
there is no preferential direction from which comets
come.

5. The Oort Cloud

6. Comet Halley

7. Bayeaux Tapestry
Norman Invasion of 1066

8. Comet Halley 1910
•Pope Callixtus III
excommunicated
Halley's Comet in 1456
•In 1910, charlatans sold
"comet pills"
Orbit

9. Comet Nucleus

10. Comet of 1577

11. Hyakutake

12. Hale-Bopp

13. Comet West

14. The Cause of Meteor Showers
P55/Tempel-Tuttle

15. Why After Midnight is Best
Rotational
Velocity
Orbital
Velocity
Midnight

16. Shower Radiant

17. The 1833 storm

18. The 1966 storm

19. 1997 Leonids from Orbit

20. Two Showers for Halley

21. Sporadic Meteors
Irons Stony-Irons
Chondrites Carbonaceous
Chondrite
Achondrite

22. Barringer’s Crater
An iron meteorite 100 feet across and 70,000 tons
slamed into the Earth at about 43,000mph in the
Arizona desert near Flagstaff 40,000 years ago.
Barringer Crater is 4,100 feet wide and 571 feet
deep.

23. Other Impact Craters

24. Tunguska, 1908

25. How Much Damage?

26. Asteroids
Apollo
Trojans

27. Ida - Dactyl

28. Gaspra

29. Kirkwood Gaps

30. Asteroids Elsewhere

32. Sedna

33. End of Section