Radio signal (IMAGE) Ruhr-University Bochum Caption The radio signal is as unique as a fingerprint. Credit Michael Schwettmann Usage Restrictions The image may only be used for reporting about Ruhr-Universität Bochum. 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.