Astroids An asteroid named Gaspra and the space probe Galileo Asteroids are sometimes called minor planets, the first one was found by accident in 1801 and named Ceres. They range in size from that of a small mountain to a size of over one quarter of our moon.
Ceres is the largest known asteroid and is a little more than one quarter the size of our moon.
If a large asteroid were to hit our planet it would likely destroy much of the life on this planet. Some scientist believe this is what caused the dinosaurs to die out around 65 million years ago. Most asteroids re side in an area called the asteroid belt, between Mars and Jupiter. The photographs above and below were taken by the space probe Galileo in 1991, the asteroid above is called Gaspra, the asteroid below is Ida . Asteroids may be the remains of a time long ago when our solar system was formed.