Problem
A. The basic experiment described here is to measure the mass of the rings of Saturn as Cassini moved outward from Saturn towards the rings. If the rings has no mass, how would you expect them to affect Cassini's orbit as Cassini approach them: Would it speed up, slow down or neither? If the rings were very massive, what effect would you expect as Cassini approach them: Would it speed up, slow down or neither?
B. The rings have been measured to be 15.4 million billion metric tons, but they were predicted to be 28 million billion metric tons. Was the measured Doppler shift due to the rings larger or smaller than the expected shift? How do you know?
C. The article states that "if scientist can weigh Saturn's rings, they could estimate the amount of time it would take for them to accumulate enough contaminants to get 1 percent impure and thus calculate their age. Why does the total mass of the rings matter in this analysis?
D. What is the most likely origin for the contaminants that darken the rings?