Planets that are orbiting a star other than the sun are extrasolar planets. So far Astronomers and Scientists together have found 134 extrasolar planets. An exoplanet is another word for extrasolar.
![solar-system](http://i534.photobucket.com/albums/ee346/mccdconan/goodmodel.png)
You can see the structure of the solar-system clearly on the labelled diagram above, but you can't see the asteroid belt. It lies between Mars & Jupiter. Asteroids on Jupiter's orbit are Trojan Asteroids).