This area is called, the Asteroid Belt. Other areas that contain objects such as these, are just beyond Pluto called the Kuiper Belt, than even further called the Oort cloud. Pluto is spherical like a planet, yet is practically dead. Since their discovery, more than 500 have been found, but over 300 were lost, and that's not good.
Asteroids follow nearly circular paths as do planets.
Asteroids, mainly, are most visible because of the reflecting sunlight off of them. The asteroid, Vesta, is big and bright enough to be seen with the naked eye. The surface of these massive objects isn't well known, except that they probably look like those of meteors. That is smooth and round with a cratered surface. Asteroids are thought to be rocky and metallic with perhaps billions of tons of precious metals and elements such as gold and silicon.