If there were no massive objects these things would go flying off, or at least go at a much slower rate because all that determines how they go around is how much mass is inside its orbit.
如果没有大质量的物体存在，这些星体都将四散而出 或者说至少运动的速率对大幅下降 这是因为，对它们如何运动起到决定性作用的是 它的轨道内部存在多少的物质