You Don't Look A Day Over 100 Million, Rings Of Saturn
"Saturn is famous for its lovely rings, but a new study suggests the planet has spent
most of its 4.5 billion years without them."
"That's because the rings are likely only 10 million to 100 million years old, according to a newly published report in the journal Science that's based on findings from NASA's Cassini probe."
"Cassini spent some 13 years orbiting Saturn before plunging down and slamming into its atmosphere. During its final orbits, the spacecraft dove between the planet and its rings. That let scientists measure the gravitational effect of the rings and get a good estimate of the ring material's mass."
What they found is that it's only about 40 percent of the mass of Saturn's moon Mimas, which is way smaller than Earth's moon.