Figure 1 (IMAGE) Tohoku University Caption The compressional velocity of pure iron at high pressure as determined in the present work (blue symbols) compared to the highest previous determination using these methods (open symbol) and to the known relation of the inner core determined from seismic observations (dashed red line with stars). Credit Daijo Ikuta Usage Restrictions Reporters may use freely these materials in news coverage with appropriate credit information. 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.