John Tarduno, University of Rochester (IMAGE) University of Rochester Caption Geophysicist John Tarduno of the University of Rochester and the "SQUID" -- a Superconducting Quantum Interference Device -- that allows him to detect the strength of the ancient Earth's magnetic field. Credit University of Rochester Usage Restrictions None 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.