It is shown that the hypothesis that comets originate in the vicinity of each of the giant planets is consistent with the idea that these planets possess rings. It is suggested that the rings of Uranus, the probable gaseous ring around Jupiter and the clouds surrounding Io are rapidly evolving phenomena - the same may also even be true of Saturn's rings - which is to be expected of agglomerations of cometary meteoroids losing their icy constituents by sublimation.