Zenomagnetic core-mantle coupling and the rotation of Jupiter's Great Red Spot

Abstract

Fluctuations of the order of several seconds in the period of rotation of Jupiter's Great Red Spot have been observed by Reese and Solberg (1966) to occur within intervals of not more than a few months. On Hide's (1961) hypothesis that the Red Spot is a persistent feature attached to the solid surface of the planet, these fluctuations may indicate an internal redistribution of Jupiter's angular momentum. Evidence for a strong zenomagnetic field and for a transition from the molecular to the metallic phase of hydrogen at pressures of a few Mb have led Gallet (1961) and Runcorn (1967) to suggest that angular momentum may be transferred between the solid molecular hydrogen mantle and a liquid metallic core. Adopting their model for Jupiter's interior and using the theory of electromagnetic coupling which has successfully explained the irregular changes in the Earth's rotation period, the electrical conductivity of the Jovian mantle can be estimated. The result is not inconsistent with such slight evidence as exists for changes in the rotation period of the decametre radio sources.