After Mars comes the asteroid belt, a girdle of rocky objects between the orbits of Mars and Jupiter, about 186 million to 370 million miles (300 million to 600 million kilometers) from the sun.
Asteroids are small, airless rocky objects revolving around the sun, but are too small to be planets. They are also known as planetoids or minor planets. Most asteroids lie in the asteroid belts, but there are others across the solar system.
Asteroids represent the leftovers from the formation of our solar system about 4.6 billion years ago. They are dirty bastards that could rip your spacecraft to shreds in an instant. If you had a spacecraft. You wish you had a spacecraft.