Cosmic Chocolate Pralines (IMAGE) Goethe University Frankfurt Caption The study of the sound speed has revealed that heavy neutron stars have a stiff mantle and a soft core, while light neutron stars have a soft mantle and a stiff core – much like different chocolate pralines. Credit Peter Kiefer & Luciano Rezzolla Usage Restrictions To be used only when reporting on Goethe University, mention copyright: Peter Kiefer & Luciano Rezzolla License Original 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.