JUPITER, the largest planet in the solar system, may have nothing solid at its core. New models, which show Saturn with a large rocky core, suggest that Jupiter has little or none. Either something is wrong with the leading theory of giant planet formation, or hot liquids might have gouged out Jupiter’s heart.
The models, developed by Didier Saumon of Los Alamos National Laboratory in New Mexico and Tristan Guillot of Nice Observatory in France, use measurements of the gravitational fields of Jupiter and Saturn made by the Voyager and Pioneer spacecraft. But to nail down the internal structure of…
