The formation of the solar system is still a very open question in astronomy. Some things we understand, some things we don't. New work by astronomers proposes that Saturn's rings and moons may have formed billions of years after the Sun burst into light and Saturn and its brethren took shape.
Saturn's rings were first discovered by Galileo in 1610, but the first moon wasn't detected until 1655, when Dutch astronomer Christiaan Huygens took advantage of advances in telescope technology to study the planet in more detail. It was originally assumed that the rings (and moons) formed simultaneously (astronomically speaking) along with the entire solar system. However, evidence to the contrary is now being found. In 2012, astronomers in France found that some the moons closer in are actually spiraling slowly away from Saturn.
Building on that research, astronomers at SETI and the Southwest Research Institute have used computer simulations to dynamically model the evolution of Saturn's inner moons. The results suggest that moons beyond the orbit of Rhea are likely the oldest, but the ones closer in are younger and their orbits around Saturn haven't had as much time to evolve - i.e., their current locations are not far from where they likely formed. Ages for these moons based on these assumptions come out to less than 100 million years old (which likely applies to the rings as well).
Lead researcher, Matija Cuk, summarized it thusly:
"Our best guess is that Saturn had a similar collection of moons before, but their orbits were disturbed by a special kind of orbital resonance involving Saturn's motion around the Sun. Eventually, the orbits of neighboring moons crossed, and these objects collided. From this rubble, the present set of moons and rings formed."
This means that while dinosaurs were roaming the Earth during the Cretaceous Period, Saturn was ringless! Mind. Blown. Those dinosaurs will never know the beauty they missed.
Here's some more geek from the week: