Red Giant (IMAGE) Max Planck Institute for Solar System Research Caption Towards the end of their lifetime, main sequence stars, such as the Sun, turn into red giants. The layer in which massive plasma flows transport hot material to surface then expands to the core. In this way, nuclear material can reach the surface of the star - and allows for an indirect view into the interior. Credit SAGE-group/MPS 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.