How do we really measure the world we live in and why did scientists decide it was time to redefine the foundations of measurement itself? 

In this lecture, Nobel Prize winner Prof. Dr. William D. Phillips explores the most radical transformation of the International System of Units (SI) since its origins in the French Revolution. Instead of relying on physical artefacts, all base units are now defined by fixed values of natural constants. The talk explains why this reform was necessary and how it works.

Date: Monday, 16 March 2026
Time: 16:15–17:15
Venue: Grosser Hörsaal 1.03
Entrance: St. Johanns-Ring 25, 4056 Basel

Organised by: Department of Physics
Host: Prof. Dr. Philipp Treutlein