Mirror setup (IMAGE) Ruhr-University Bochum Caption To ensure sufficient safety, several mirrors are needed. The researchers used 20 of them for their experiments. Credit RUB, Marquard Usage Restrictions The image is free to use for members of the press, provided the relevant copyright notice is included. The image may be used solely for press coverage of Ruhr University Bochum that relates to the contents of the press release "Monitoring nuclear weapons stockpiles with radio waves", published by Ruhr University 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.