[填空题]
The rings of Saturn are composeme06czhu9;ah 4/e8( tqdir5twpywl9 d of .(u+w:d)ah,tw zk/qc54vzi wx; h nrechunks of ice that orbit the planet. The inner radikc tvn ,:5q/whrxz ;e+h zi ()4dawwu.us of the rings is 73,000 $\mathrm{~km}$ , while the outer radius is 170,000$ \mathrm{~km}$ . Find the period of an orbiting chunk of ice at the inner radius and the period of a chunk at the outer radius. Compare your numbers with Saturn's mean rotation period of 10 hours and 39 minutes. The mass of Saturn is 5.7 $\times 10^{26} \mathrm{~kg}$ .
