The marble is a solid sphere, so its mass is distributed closer to its center.

达尔是一个实心球，所以它的质量是分布的 靠近其中心。

Early research assumed that hailstones fell like solid ice spheres and showed very high fall speeds, even for very small hailstones.

早期研究假设冰雹像固体冰球一样下落， 并且显示出非常高的下落速度， 即使对于非常小的冰雹也是如此。

However, recent research outside of NSSL using 3-D printed casts of real hailstones suspended in a vertical wind tunnel has repeatedly shown that natural hailstones fall more slowly than solid ice spheres.

然而， 最近在 NSSL 之外的研究使用 3D 打印的真实冰雹模型悬浮在垂直风洞中， 一再表明天然冰雹比固体冰球下落更慢。