Saturn#8217;s bulk composition is thought to be about 75% hydrogen with the rest being helium (bar some trace components), explains Nicolas Altobelli, the European Space Agency#8217;s Cassini project scientist.
#8220;It#8217;s expected that the heavier helium is sinking down,#8221; he told News. #8220;Saturn radiates more energy than it#8217;s absorbing from the Sun, meaning there#8217;s gravitational energy which is being lost. And so getting a precise measure of the hydrogen and helium in the upper layers sets a constraint on the overall distribution of the material in the interior.#8221;
#8220;What#8217;s going on? Is something shielding our ability to see the offset, or do we simply need a new theory? But without the tilt, without being able to see the tiny wobble, we cannot be more precise about the length of a day.#8221;
The Cassini probe is beginning the final phase of its mission to Saturn.