Chaos Beneath the Calm

This pic was discussed on a buncha astronomy blogs a few weeks ago (the Planetary Society Blog has the best discussion). It's a close-up of Saturn's rings. Ignore the big pointy shadow on the right, that's from Mimas, a moon of Saturn. Note instead the jagged shadows along the diagonal of the pic, where one ring is casting shadows on the next ring in. Cool, huh? No one is quite sure what is causing it, though the best guess is there is a lot of variation in size in the particles that make up that specific ring (though, interestingly, not the others). Alternately, it could be a bunch of smaller particles clumping up, due to gravitation. So the rings are not so much flat surfaces as a bunch of tiny moonlets bouncing around, colliding, clinging together for awhile, blasting apart, reforming into new groups. I like the idea of such a seemingly serene structure having all that chaos teeming just beneath the surface. Metaphors abound.

The reason, by the way, the shadows can be seen at all is that the rings are very close to being parallel to the sun's rays (think of trees casting long shadows in late afternoon).

Here's a close-up.