Seminarium Teorii Względności i Grawitacji

Speed of light is one of the most fundamental constants of Nature and its constancy lies at the foundations of theory of relativity. The first measurements of the speed of light in human history were made by astronomers: Ole Roemer and James Bradley. Since then laboratory experiments provided the most accurate measurements of this quantity. It has been only quite recently when the astronomical measurements of c reentered the scene - this time using extragalactic objects.In may talk I will review current ideas of how to measure the speed of light at cosmological scales. In particular, our results obtained so far will be presented. I will also digress on a broader context of such studies, which is the empirical support of the paradigm that the laws of physics, and fundamental constants in particular, are the same on the Earth now as they were in a distant universe across its history.