It therefore seems that most asteroids are not left over from the first generation of planetesimals.That generation must have been cleared out, presumably by Jupiter.

• 然后，力的平衡将促使气体加速环绕中心恒星，结果造成附近的颗粒不再感受到逆风，反而是令它们提升速度的顺风，因而阻止它们进一步向内迁移。