Saturn's Electromagnetic Environment

Thirty years ago, spacecraft discovered radio noise coming from Jupiter, and scientists were able to tie that noise to the rotation of the planet, using it to accurately measure the length of the Jovian day. So, when Cassini detected similar radio noise emanating from Saturn, they assumed they could do the same thing. They were wrong. Extended monitoring by Cassini has shown that the noise in the northern hemisphere of Saturn has a different rotation rate than the noise in the southern hemisphere. The noise, therefore, can not be tied to a definite, solid surface. Further, over time, the lengths of the bursts of the noise varies between hemispheres, being longer in the north, say, and cycling to become longer in the south. This radio noise seems connected to Saturn's magnetosphere. The strength of auroral activity on Saturn can be related to the radio bursts, for example. The magnetosphere, in turn, is influenced by the Sun. The changing lengths of the bursts, north to south, is corelated with the change of seasons on Saturn, from winter to spring. Scientists think the noise is a product of the high atmosphere.