Dueling spacecraft look deep into Saturn and Jupiter.

Abstract

Measures by two NASA spacecraft, Cassini and Juno, are revealing the interiors of the solar system9s gas giants like never before. Using minute Doppler shifts in radio signals from the spacecraft, scientists have been able to map the shape of gravity fields at both planets, allowing them to infer the density and movements of material deep inside. They have revealed that, at both planets, the surface-shaping winds extend down to a midway point where hydrogen turns into a semiconductor and the winds9 momentum is quenched by the planets9 magnetic fields. Studies of the deep interior, however, remain more uncertain. Juno is only halfway through its mission, and Cassini burned up in Saturn9s atmosphere in 2017. Cassini9s study of Saturn9s rings, however, could reveal a new way to gauge the planet: The rings feature wavelike patterns that record evidence of oscillations from its deep interior.