Asteroids:

Asteroids are the biggest of the smaller bodies in our solar system. These fragments of rock orbit the sun and are mostly found in between the Mars and Jupiter orbits. One theory of how the asteroids got there is that they might be the remains of a planet that was once there, that had a massive collision long ago. Another theory is that they might be left over rocky matter that never turned into a planet.

The three types of Asteroids consist of carbon, iron/nickel, and silicate minerals. A very special type of asteroid, and very dangerous type are called Trojan asteroids or earth-grazers. These types of asteroids are extremely dangerous, because they have a chance of hitting the earth. Earth-grazers have an elongated elliptical orbit which allows them to come very close to the earth, and possibly even hit the earth.


http://sse.jpl.nasa.gov/planets/profile.cfm?Object=Asteroids
http://sse.jpl.nasa.gov/planets/profile.cfm?Object=Asteroids
http://www.nasa.gov/centers/jpl/images/content/173503main_pia00136-browse.jpg
http://www.nasa.gov/centers/jpl/images/content/173503main_pia00136-browse.jpg

The botom picture is the asteroid Ida which has it's own moon named Dactyl