Saturn's Interior (IMAGE) University of California - Berkeley Caption Saturn's interior is mainly composed of three layers: a deep inner core made mostly of heavy elements, with a liquid metallic hydrogen envelope, surrounded by a molecular hydrogen layer. Cassini measurements are telling scientists about the size of the core, the flow of winds in the atmosphere, and the mass of the rings. Credit Background image from NASA/JPL-Caltech Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.