A 2-Level System of Circulation inside the Sun (image) NASA/Goddard Space Flight Center Share Print E-Mail Caption Observations by the Helioseismic and Magnetic Imager on NASA's Solar Dynamics Observatory show a two-level system of circulation inside the sun. Such circulation is connected to the flip of the sun's north and south magnetic poles that occurs approximately every 11 years. Credit Stanford Usage Restrictions None Share Print E-Mail 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.