Professor Jean-Philippe Uzan from the Paris Institute of Astrophysics, will give a special Department of Physics and MeASURe colloquium talk entitled, "Fundamental constants - The new SI and general relativity" 

In the new international system of units to be adopted at the end of this year, fundamental constants play a central role in the definitions of the units. This introductory lecture will come back on this choice as the endpoint on a long historical quest to base units on the most universal objects we know. It will discuss the nature of fundamental constants in the laws of physics in order to highlight the interplay with theory. To finish, it will discuss the hypothesis that these parameters are constant both from a theoretical and experimental perspective and the link with the equivalence principle at the heart of general relativity.