3. Earth Science Chapter 29 Section 4
Asteroids
Largest of the small bodies in our solar system
50,000 have been observed there may be millions more
All have ellipse orbits
The largest is Ceres at about 1,000 km
Most are between Mars and Jupiter, in the asteroid belt

5. Earth Science Chapter 29 Section 4
Asteroids
Three types of asteroids based on there composition
Carbon materials make asteroids with a dark appearance
Iron and Nickel asteroids have a metallic appearance
Silicate look like the surface of the planet earth

7. Earth Science Chapter 29 Section 4
Asteroids
The asteroid belt exist because gravity from Jupiter may have prevented a planet from forming
All the material in the belt would not be as massive as our moon
Trojan asteroids travel in the same orbit as Jupiter, just ahead and just behind
Earth grazers travel in orbits that cross the our orbit on there way around the Sun

9. Earth Science Chapter 29 Section 4
Comets
Made from rock, dust, methane, ammonia and ice
The core or nucleus is made of rock, metals and ice; between 1km and 100km diameter
The coma is a dust cloud that forms around the comet as it approaches the sun
The tail is formed from the dust being pushed back by the solar winds
Comets originate from the Oort cloud
Some have a long period orbit that takes thousands to millions of years to reach the sun
Some have a short period, less then 100 years. Halley’s comet comes by every 76 years, it last passed in 1986.

11. Earth Science Chapter 29 Section 4
Meteoroids
Most are between 1mm and 1 cm in diameter
As they cross our atmosphere most will burn up as a meteor or shooting star
Some will vaporize quickly in a flash of light called a fireball, a loud sound may follow
If a large number enter our atmosphere at one time it is called a meteor shower
About 1 million kg fall every day
Sometimes some will survive the entry into our atmosphere to become a meteorite
Most are less then 1kg

12. Earth Science Chapter 29 Section 4
Meteoroids
Three types of meteoroids exist
A stony meteorite is rocky materials like the earth’s surface, some have carbon materials found in living organisms
Iron meteoroids are easier to spot since they do not look like rocks
Stony-iron meteoroids are the rarest
They are mostly formed from asteroid collisions and are 100 million years older then the earth or moon

13. Earth Science Chapter 29 Section 1-4
Geocentric
Retrograde motion
Epicycles
Heliocentric
Ellipse
Focus
Astronomical unit
Orbit period
inertia
Jovian Planets
Terrestrial Planets

14. Earth Science Chapter 29 Section 1-4
Asteroids
Asteroid Belt
Trojan Asteroids
Earth-grazers
Comets
Coma
Oort Cloud
Long period Comets
Short period comets
Meteor
Fireball
Meteor shower
Meteorite
Stony meteorites
Iron meteorites
Stony-iron meteorites