But in this case it's a momentum of spin, which depends on the object's size and how rapidly it's rotating.

但这里的动量是旋转的，取决于物体的尺寸和转速。

These ranged in size from grains of dust up to objects the size of planets, and that meant there were lots of collisions.

这些粒子从一粒尘埃到行星的尺寸都有，这就意味着经常会有很多的碰撞发生。