<Tr> <Td> Cassini image mosaic of the unlit side of the outer C Ring (bottom) and inner B Ring (top) near Saturn's equinox, showing multiple views of the shadow of Mimas . The shadow is attenuated by the denser B ring . The Maxwell Gap is below center . </Td> <Td> A spiral density wave in Saturn's inner B Ring which forms at a 2: 1 orbital resonance with Janus . The wavelength decreases as the wave propagates away from the resonance, so the apparent foreshortening in the image is illusory . </Td> <Td> Dark B Ring spokes in a low - phase - angle Cassini image of the rings' unlit side . Left of center, two dark gaps (the larger being the Huygens Gap) and the bright (from this viewing geometry) ringlets to their left comprise the Cassini Division . </Td> </Tr> <Table> <Tr> <Td> Cassini image of the sun - lit side of the rings taken in 2009 at a phase angle of 144 °, with bright B Ring spokes . </Td> <Td> Pan's motion through the A Ring's Encke Gap induces edge waves and (non-self - propagating) spiraling wakes ahead of and inward of it . The other more tightly wound bands are spiral density waves . </Td> <Td> Radially stretched (4x) view of the Keeler Gap edge waves induced by Daphnis . </Td> </Tr> </Table> <Tr> <Td> Cassini image of the sun - lit side of the rings taken in 2009 at a phase angle of 144 °, with bright B Ring spokes . </Td> <Td> Pan's motion through the A Ring's Encke Gap induces edge waves and (non-self - propagating) spiraling wakes ahead of and inward of it . The other more tightly wound bands are spiral density waves . </Td> <Td> Radially stretched (4x) view of the Keeler Gap edge waves induced by Daphnis . </Td> </Tr> <Table> <Tr> <Td> Prometheus near apoapsis carving a dark channel in the F Ring (with older channels to the right). A movie of the process may be viewed at the Cassini Imaging Team website or YouTube . </Td> <Td> F ring dynamism, probably due to perturbing effects of small moonlets orbiting close to or through the ring's core . </Td> </Tr> </Table>

Who explained first what the rings of saturn are