While the Sun gravitationally pulls the asteroids inward, the gravitational pull of Jupiter is pulling the asteroids outward. Since the belt is closer to Jupiter than it is to the Sun, Jupiter exerts more of an influence on the asteroids. As a result, the asteroids are held in orbit away from the inner planets.
The StarChild site is a service of the High Energy Astrophysics Science Archive Research Center (HEASARC), Dr. Alan Smale (Director), within the Astrophysics Science Division (ASD) at NASA/GSFC.
The StarChild Team
StarChild Graphics & Music: Acknowledgments
StarChild Project Leader: Dr. Laura A. Whitlock
Responsible NASA Official: Phil Newman