1. Bell work
Have scientists ever brought extraterrestrial material to Earth? Scientists have studied rocks from Mars and other parts of the solar system. How have scientists obtained these rocks?
Record your answer in your science journal.

2. Comets, Meteors, and Asteroids

3. Today’s Objectives
Explain why comets, asteroids, and meteoroids are important to the study of the formation of the solar system.
Describe the similarities of and differences between asteroids and meteoroids.
Explain how cosmic impacts may affect life on Earth.

4. Comets
Small body of ice, rock and dust loosely packed together that orbits the sun
A comet is a “dirty snowball” about the size of an earth mountain. (dirt and ice)
Comets’ orbits are usually very long, narrow ellipses.
They produce tails of gas and dust when they approach the sun.
Look like “shooting stars” but can move much slower.

5. Comet Parts
Tails
Ion-electrically charged ions, always points away from the sun
Dust- follows the orbit of the comet
Gas-follows the orbit of the comet also
Can extend millions of km

6. Comet Parts
Nucleus
Averages 3 miles in diameter, by can be between ½ and 100 km
Solid, rocky, icy center
Shows different features as it nears the sun
Coma forms a large halo around the nucleus of a comet as it nears the sun
The Coma’s halo is made of dust and gas

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

9. Orbit
Highly elongated
Very elliptical

10. Oort Cloud
Oort cloud- sphere that surrounds the solar system 1 light year away from the sun made of dust and gas

11. The Oort Cloud

12. Kuiper Belt- outside orbit of Neptune- made of dust and rocks- where most dwarf planets are found.

13. Comet names
Comets are often named after the person who discovers them!
Maybe the next one could be named after you!

14. Comet Halley

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

16. Halley’s Comet (1986)

17. Halley’s Comet…. Orbits every 76 years

18. Hyakutake

19. Winter and early spring of 1997
Comet: Hale-Bopp
Winter and early spring of 1997
Next sighting: 4380

20. Hale-Bopp

21. Comet West

22. Today’s Objectives
Explain why comets, asteroids, and meteoroids are important to the study of the formation of the solar system.
Describe the similarities of and differences between asteroids and meteoroids.
Explain how cosmic impacts may affect life on Earth.

23. Meteoroids, Meteorites, and Meteors
Meteoroid- small rocky body often made of rock, metal, or dust.
Meteorite- meteoroid that hits the Earth
Meteoroids survive as they pass through the atmosphere and hit Earth’s surface
Meteor- meteoroid that burns up in the Earth’s atmosphere
Shooting stars are not actually stars. These flashes of light across the sky are small bits of rock burning up in the Earth’s Atmosphere. They often move very fast across the sky.
They are called “fireballs” when it creates a long streak of light as it gets close to the ground.

24. 3 types
Stony
Metallic
Stony-iron

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

26. The 1833 storm

27. The 1966 storm

28. 1997 Leonids from Orbit

29. Two Showers for Halley

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

31. 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.

32. Other Impact Craters

33. METEOROID: A piece of stone or metal that travels in outer space.
SUMMARY
METEOROID: A piece of stone or metal that travels in outer space.
METEOR: An object from space that becomes glowing hot when it passes into Earth's atmosphere.
METEORITE: A piece of stone or metal from space that falls to Earth's surface.

34. Today’s Objectives
Explain why comets, asteroids, and meteoroids are important to the study of the formation of the solar system.
Describe the similarities of and differences between asteroids and meteoroids.
Explain how cosmic impacts may affect life on Earth.

35. Asteroids
Small rocky bodies in orbit around the sun. (larger than meteoroids)
Have the same compositional matter as the Terrestrial planets
Located between Mars and Jupiter in the Asteroid Belt.
Ceres was the largest asteroid ever discovered
Now it is classified as a Dwarf Planet!

37. Asteroids
Apollo
Trojans

39. Ida - Dactyl

40. Gaspra

41. Today’s Objectives
Explain why comets, asteroids, and meteoroids are important to the study of the formation of the solar system.
Describe the similarities of and differences between asteroids and meteoroids.
Explain how cosmic impacts may affect life on Earth.