[填空题]
The rings of Saturn sgucwph59nv/*9k(du:a2vi k*+scl 4a xjd6 yare comad/q 2n*1 zxwuposed of chunks of ice that orbit the planet. The innq*2/ua1w n zxder radius 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 $\times 10^{26} \mathrm{~kg}$ .
