Gas clusters that push the protoplanet outward can sometimes exert stronger forces than those that push inward .

气体星团推动原行星向外的推力可能在某些时候强于那些使它向内的推力。

Another probe , dawn , is currently at vesta ( a protoplanet ) , but will move onto ceres after a year of study .

另一个探测器dawn目前已到达维斯塔（一颗原行星），但是进行过一年研究后将转到克瑞斯。