The tiny planets
Just as there are giant planets in the sun’s family—Jupiter and
Saturn—there are also “dwarf” planets. These small planets are called
asteroids.
Asteroids circle the sun in a ring between Mars and Jupiter. There are
thousands of them. Most are less than a mile (1.6 kilometers) across.
Some are several hundred miles (kilometers) across. The largest
asteroid, named Ceres, is about 600 miles (1,000 kilometers) wide.
The larger asteroids are nearly ball-shaped, like the bigger planets.
But the smaller asteroids are bumpy and jagged. They may be pieces of
larger asteroids, for asteroids often bump into each other and break
into smaller bits. When this happens, they are knocked out of their
paths and into new ones. They become meteoroids that sometimes collide
with other planets. Such collisions made the craters on the moon, Mars,
and Mercury. Bits of asteroids also become the “shooting stars” that we
see from earth.
