The full mass of the asteroid belt is approximately four percent that of the moon, twenty-two that of Plato, and roughly twice that of Pluto's moon Charon (whose diameter is 1,200km) Ceres, the asteroid belts only dwarf planet is about nine hundred and fifty kilometers in diameter. The asteroid belt is mostly empty. The asteroids span over such a large volume that it would be impossible to reach an asteroid without aiming carefully.
The whole mass of the asteroid belt is estimated to be between 2.8 times 10 to the twenty-first power and 3.2 times ten times twenty-one kilograms. Approximately one-third of the asteroids in the belt are components of an asteroid family. There are about 20-30 associations of asteroid families.
