Mysterious Radio Signals from Space Are Much Better Test of Einstein's General Relativity (image) Penn State Share Print E-Mail Caption This illustration shows how two photons, one at a high frequency (nu_h) and another at a low frequency (nu_l), travel in curved space-time from their origin in a distant Fast Radio Burst (FRB) source until reaching the Earth. A lower-limit estimate of the gravitational pull that the photons experience along their way is given by the mass in the center of the Milky Way Galaxy. Credit Purple Mountain Observatory, Chinese Academy of Sciences Usage Restrictions The image credit must be pubished along with the image. Share Print E-Mail 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.