Atomic motion still (IMAGE) University of Texas at Austin Caption A model of iron atoms on the move in Earth's inner core. The model demonstrates how iron atoms are expected to move about in the Earth’s inner core over 10 picoseconds.. One picosecond is one trillionth of a second. Credit Zhang et al. Usage Restrictions Include credit 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.