Queen of the Asteroid Belt
With a diameter of 933 km (580 miles), Ceres is the undisputed ruler of the asteroid belt. The space rock accounts for a quarter of all the mass of all the thousands of known asteroids in or near the main asteroid belt.

Small Change
If you could lump together all the thousands of known asteroids in our solar system, their total mass wouldn't even equal 10 percent of Earth's Moon.

Asteroid Assault
Asteroids have hit every planet in our solar system. Most space rocks that hit Earth burn up or slow down enough not to cause serious damage. Evidence of what happens when they don't can be seen at Barringer Crater in Arizona - a giant hole almost 1.6 km (1 mile) across and 175 meters (570 feet) deep.

Close Call
An asteroid named 1950 DA is considered one of the greatest known threats to crash into Earth. Fortunately, the odds of an impact are fairly slim. The asteroid won't arrive until March 16, 2880 so we have a few hundred years to watch it and make certain it will miss Earth.

Tiny Guardian
Asteroids are often called minor planets. Some even have moons. Back in 1994, NASA's Galileo spacecraft found a tiny moon - about 1.5 km (1 mile) across - orbiting Asteroid Ida. The first known moon of an asteroid was named Dactyl, after the protectors of the young Greek god Zeus.

Touchdown
After NASA's NEAR spacecraft had completed its intensive study of Asteroid Eros, mission controllers decided to try to land the spacecraft. Despite the fact it wasn't designed for landing, NEAR successfully touched down on Eros in 2001 - and went into the record books as the first to land on an asteroid.