launched eighteen years ago, the cassini orbiter is set to crash in to saturn next september, ending its mission to collect data, including these true colour images, on saturn and its moons and rings. saturn’s main rings, composed mostly of ice, are thought to have formed only a few hundred million years ago, long after the planet, and the solar system itself, were birthed some four and half billion years ago.
though a hundred and seventy million miles in diameter, the main rings are only half a mile thick, with the brighter bands showing areas of greater density, and the darker, less dense areas swept relatively clear by the gravity of saturn’s moons - clear enough, anyways, for the cassini orbiter to pass through one of the gaps basically unscathed.
there is no consensus on how the rings were created, but a medium sized moon, either shattered by a meteor or pulled apart by the planet’s gravity, would account for the entire mass of the rings. there is, however, consensus that in about fifty million years saturn’s gravity will have pulled in the rings and swallowed them up.
saturn has over forty moons, including one found within a ring gap. these photos show the distant rhea and titan - the latter of which is larger than mercury and has its own atmosphere and hydrocarbon lake - and the inner most mimas and enceladus - the latter being notable for its encompassing liquid ocean of water and geothermal activity.