Chemical Compass Molecule (IMAGE) Arizona State University Caption Upon excitation with light, an electron moves from one end of the molecule to the other. The time it takes for this electron to return to its initial position is sensitive to the magnitude and direction of magnetic fields similar to those of the Earth. Birds may use a similar phenomenon to navigate. Credit Graphic by Devens Gust, Arizona State University Usage Restrictions Credit line: Graphic by Devens Gust, Arizona State University License Licensed 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.