Physicists demonstrate with unprecedented accuracy the constancy of the speed of light

Several leading quantum gravity theories predict that there is a dependence of the speed of light on photon energy, which would bridge incompatibilities between general relativity and quantum physics. A collaboration between the Universitat Autònoma de Barcelona (UAB), the Institute of Space Studies of Catalonia (IEEC), the Centre for Space Studies and Research (CEREs-UAB), the University of Aveiro (Portugal) and the University of Algarve (Portugal) has sought to prove this dependence based on the analysis of astrophysical observations of very energetic light from gamma-ray emissions from very distant sources. With unprecedented accuracy, the research shows that the speed of light remains a universal constant.