... solar system . ... Tour the Solar System . ... Asteroid belts of just the right size are friendly to life . ... In the top panel, a Jupiter-sized planet migrates through the asteroid belt, scattering material and inhibiting the formation of life on planets. The second scenario shows our solar system model: a Jupiter-sized planet that moves slightly inward but is just outside the asteroid belt. ... Material from the hefty asteroid belt would bombard planets, possibly preventing life from evolving. ...