Mars Core (IMAGE) ETH Zurich Caption Analysis of Martian seismic data recorded by the InSight mission in combination with first-principles simulations of the seismic properties of liquid metal alloys have revealed that Mars’s liquid iron core is surrounded by a 150-km thick molten silicate layer, as a consequence of which its core is smaller than previously proposed. The decrease in core radius implies a higher density than estimated earlier and is compatible with a metal core consisting of 9–15 wt% of light elements, chiefly S, C, O, and H. Credit ©2023 Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International (CC BY-NC-SA 4.0) - Thibaut Roger - NCCR PlanetS - ETH Zurich. Usage Restrictions Credit must be given to the creator. Only noncommercial uses of the work are permitted. Adaptations must be shared under the same terms. License CC BY-NC-SA 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.