Homework due in class, Nov 21. Remember to show your work, neatly.

1) A radio measurement is made of two points on Saturns rings. A measure at a point 1000 km above the atmosphere of Saturn (Saturn is 60,000 km in radius) results in a 31+2.5x10^-5 cm return echo from a 31 cm pulse. At a second point, 5000 km above the atmosphere of Saturn, gives a return echo of 31+2.4x10^-5 cm for a 31 cm pulse. What is the rotation velocity at these points? Why does this show that the rings of Saturn are not solid? (4 points) (Answer = 0.24 km/s and 0.23 km/s)

2) If the mass of Jupiter collapses from very far away and all the potential energy is converted into heat, how hot was Jupiter when it formed? If Jupiter was 1/100 the luminosity of the Sun, how long till it cooled off? (6 points) (Answer = 5.5x10^6 K, t=1.5x10^11 yrs)

3) Would Jupiter be able to maintain a hydrogen rich atmosphere if moved to the distance of the Earth's orbit? Assume Jupiter is a fast rotator. (6 points) (Answer = yes)

4) A probe entering Saturns atmosphere measures a pressure of 2 atmospheres at 100 km from the top and 100 atmospheres at 1000 km. What is the scale height of the atmosphere? (4 points) (Answer = -230 km)