An article at on Nature.com titled Saturn’s Young Rings (20 December 2017) , touts a presentation at the Fall Meeting of the AGU based on the gravitational effect of the rings on the Cassini probe. The researchers claim that this force is not strong enough to retain the rings. Using the data they calculate that the rings are young, only 100 to 200 million years old!
Although the rings are known to be primairily water ice, modern science cannot determine the origin of all this ice, since the current hypothesis is that Jupiter and Saturn are 90% hydrogen and 10% helium. The leading hypothesis is that two comets, or a comet and a satelllite collided inside the Roche limit and the pieces ended up forming the rings. No concern is offered as to the similarity in the sizes of the chuncks of ice.