Saturn's rings are raining into Saturn
After a few weeks of drawing Saturn with its rings nearly edge-on, I went looking for something that would explain what I was actually looking at, and found this two-minute video from NASA's Goddard Space Flight Center. It is theirs, not mine, and it is better than anything I could write about it.
The short version: the rings are slowly losing material into the planet. Tiny icy particles pick up an electric charge from sunlight and from micrometeoroid impacts, and once charged they can be pulled along Saturn's magnetic field lines down into its upper atmosphere. Around the middle of the video there is an animation of exactly this, grains peeling away and spiralling down towards the cloud tops. The researchers estimated the rain could fill an Olympic swimming pool in about half an hour, and that at this rate the rings could be gone in something like 300 million years.
That is a long time by kitchen standards and a very short one by planetary standards. It also fits with the idea that the rings may be much younger than Saturn itself, which I find oddly cheering. The thing in the eyepiece is not a permanent fixture. I am just here at a moment when it happens to be there.
Saturn reaches opposition in early October, so for the next few weeks it is up all night and as close and bright as it gets this year. The rings will still look like a line with a bead on it. I know a little more now about what the line is doing.