1. Comets, Asteroids, and Meteoroids

2. Year Giuseppe Piazzi discovered the first asteroid, Ceres
1801
Year Giuseppe Piazzi discovered the first asteroid, Ceres

3. 4.6
Earth years it takes the asteroid Ceres to travel around the sun (Ceres – Biggest Asteroid with a 960 km circumference)

4. 2880
Year asteroid 1950 DA will pass close to Earth – The greatest known impact hazard

5. Asteroids Asteroids are small, rocky worlds.
Most asteroids revolve around the sun between the orbits of Mars and Jupiter. (asteroid belt)

6. Asteroids
Earth has been struck many times in its history by asteroids.

8. This 142-million-year-old crater has a diameter of almost fourteen miles (twenty-two km). Like many craters on Earth, it is misleading. The raised ring that is clearly visible to the left is not the crater rim. It is an erosional remnant. The remains of the actual rim are found farther out from the ring.

10. 100 km
212 Million years old
Canada

12. The gigantic Chicxulub Crater (~110 miles diameter) in the Gulf of Mexico near the Yucatan Peninsula is about 65 million years old. (This is the one that may be connected with the extinction of the dinosaurs.)

13. Percentage of Asteroids Albedo (reflectivity)
What are they made of?
Type
Composition
Percentage of Asteroids
Albedo (reflectivity)
Carbon (C-type)
Carbon
over 75 percent
(Very dark)
Silicate
(S-type)
Metallic iron mixed with iron-silicates and magnesium-silicates
17 percent
(Relatively bright)
Metallic
(M-type)
Iron/ nickel
less than 7 percent
(Relatively bright)
Dark (D-type)
Water ice/frozen carbon monoxide mixed with rock
less than 1 percent
0.05 (Relatively dark and reddish)

17. Asteroid Ida and the tiny moon Dactyl

18. Comets
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.

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

21. Halley’s Comet Orbit… next seen in 2062

22. Oort Cloud

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

24. Deep Impact colliding with Temple1

26. Organic compounds

27. Meteoroid
A meteoroid is a chunk of rock, metal, or dust in space.

28. A Meteor: “A shooting star”
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.

29. Meteorite
Meteoroids that survive as they pass through the atmosphere and hit Earth’s surface are called meteorites.

30. There are three major types of meteorites: stone, iron and stony-iron.
There are three major types of meteorites: stone, iron and stony-iron.

31. Barringer Meteor Crater, Arizona
A meteorite can make a hole, or crater, in the ground when it hits it. The larger the meteorite, the bigger the hole.

32. 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.