The short answer is,”Because of Jupiter”. The other answers are good. But, the whole story of Jupiter, and sister giant Saturn is much more complex. The effects are much larger than the Asteroids. The following section is from NASA. I found this information provocative, and quite interesting. read more
The short answer is,”Because of Jupiter” The other answers are good. But, the whole story of Jupiter, and sister giant Saturn is much more complex. The effects are much larger than the Asteroids. read more
Most of these objects, called planetoids or asteroids — meaning"star-like" — orbit between Mars and Jupiter in a grouping known as the Main Asteroid Belt. The Main Asteroid Belt lies more than two-and-a-half times as far as Earth does from the sun. It contains billions — maybe even trillions — of asteroids. read more
Beyond the orbit of Mars lies the asteroid belt its a vast collection of rocks and ice, leftover from the formation of the solar system. It starts about 2 AU, ends around 4 AU. Objects in the asteroid belt range from tiny pebbles to Ceres at 950 km across. read more