Earth's oscillating inner core (IMAGE) University of Southern California Caption USC researchers identified a six-year cycle of super- and sub-rotation in the Earth's inner core, contradicting previously accepted models that suggested it consistently rotates at a faster rate than the planet’s surface. Credit Edward Sotelo/USC Usage Restrictions None 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.