The Nobel Prize in Physics 2005


The Nobel Prize in Physics 2005

Are the fundamental constants really constant?

Thanks to highly stabilised laser systems we can now make measurements with very great accuracy. For example, Hall has been able to verify what the theory of relativity predicts – that light has the same speed in all directions with a degree of accuracy never achieved before. The frequency comb technique enables us to go even further; we can investigate whether the fundamental constants of nature really are constant. We can still sleep soundly at night because the measurements that have been made so far show that they are constant – with an accuracy of 15 digits. But the future may have surprises in store for us when the accuracy has become even greater.

Theodor W. Hänsch
Max-Planck-Institut für Quanten optik, Garching and Ludwig-Maximilians-
Universität, München, Germany
John L. Hall
JILA, University of Colorado and
National Institute of Standards and technology, Boulder, CO, USA.

To cite this section
MLA style: The Nobel Prize in Physics 2005. Nobel Media AB 2020. Sat. 18 Jan 2020. <>

Back to top Back To Top Takes users back to the top of the page

Explore prizes and laureates

Look for popular awards and laureates in different fields, and discover the history of the Nobel Prize.