Answers in Genesis and
Creationist arguments on the age of Saturn's rings are no smarter than their arguments concerning star formation. How many mistakes can they make in just one go at it?
For one thing, the age of the planet and the age of the ring system are independent from one another see note. There is no reason why the ring system cannot be much younger than the planet in any "evolutionary" solar system. With that in mind we can tell by the "weathering" of ring particles exposed to the local environment that the rings are not likely less than 100 million years old (Compositional evolution of Saturn's rings due to meteoroid bombardment, J.N. Cuzzi & P.R. Estrada, Icarus 132 (1): 1-35, March 1998). Maybe that's where AiG got their 100 million year figure, but the notion of a disrupted satellite is a throwback to the 1950s, and not really of current significance.
The standard creationist argument is that the ring system should have a short dynamic age due to "evaporation". Aside from the fact that a "young" age for the ring system is intrinsically boring for the evolution/creation stuff anyway, that argument is a throwback to the pre-Voyager days. The Voyager visits to Saturn in 1980 and 1981 discovered amongst other things, the shepherd satellites embedded in the ring system (similar satellites were also found by Voyager at Uranus). Those satellites confine the much smaller ring particles, extending the possible dynamic lifetime of Saturn's rings much farther back than 100 million years, probably as far back as the 4.5 billion year age of the solar system.
This is all nicely discussed in Solar System Dynamics, by C.D. Murray & S.F. Dermott; Cambridge University Press, 1999 (reprinted 2001). See chapter 10, planetary Rings (pp 474-525), section 10.9, The Evolution of Rings. Even in the presence of shepherd satellites, the rings could (in a "worst case" scenario) "evaporate" in as little as 100 million years. However, if there are appropriate resonances in the motions of Saturn's satellites (which is very nearly the case), then resonance induced stability will push the ring lifetime right up against the solar system lifetime.
The AiG argument is typically pathetic. They ignore all possible inclinations contrary to their pre-conceptions, and assume a "worst case" scenario for the ring age, even when the actual orbital resonances in the system are far from it. They also wrongly assume that the age of the planetary ring system even matters. The rings of Saturn might well have formed only 100 million years ago! Why is that somehow excluded by "evolution"?
One more observation: A colleague recently commented -
... since when are evolutionists making astronomical predictions? I mean, they're SEPARATE and distinct fields of study. But, to the simplifications and vagaries of the YEC mindset, evolutionary biology is astronomy is geology is genetics is every other branch of science. Oh, well.
Remember, to a creationist "evolution" is a catch-all that includes biological, geological, cosmological and any other kind of "change with time" (i.e., evolution) all rolled into one. Indeed, they do not make any distinction between "Darwinian" (biological) evolution and cosmological evolution (planets, stars, and the Big Bang are all "fair game") since they are all in opposition to the creationists' 6000 year universe.
Note: Snelling's article Saturn's Rings - Short-Lived and Young is all about the rings losing water. That has nothing to do with the long term stability of the rings, which is a metter of orbital dynamics. There is a lot more to the ring particles than water. And, to stress a point already made, the age of the ring system and the age of the planet (and solar system) are truly independent of one another. Hence, Snelling's article is a waste of effort; even if the rings are only 10,000 years old (or 100,000,000 years old), it says nothing at all about the age of Saturn or the solar system (or the universe).