But fear not. When our solar system was forming 4.6 billion tears ago, asteroid collisions were common. In fact, we wouldn't be here if they weren't. The planets, Earth included, are the result of the ultimate cosmic calamity. As asteroids smashed into each other and got hot enough to melt together, the most of the swirling stuff around the sun gathered into planets.
Collisions are exceedingly rare today because virtually all of the stuff has been used up.
The asteroid belt is made up of the pieces of a planet that never got a chance to form because of Jupiter's gravitational pull. However, even the belt is made up mostly of empty space. If you emptied St. John Arena and put a pinhead in it, you'd have an area of greater density than the asteroid belt. It's empty, folks. You could fly through it at random 1,000 times and never see a danged asteroid.