Milchstraße (IMAGE) Johannes Gutenberg Universitaet Mainz Caption Spiralstruktur unserer Galaxie, der Milchstraße (künstlerische Darstellung) Credit Abb./©: NASA/JPL-Caltech Usage Restrictions This image may only be used in connection with the press release "Physicists analyze rotational dynamics of galaxies and influence of the photon mass", issued by Johannes Gutenberg University Mainz on March 5, 2019. 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.