The title of this issue could have been « Physics, yesterday, to-day and tomorrow ». J. Friedel and M. Petit recount
their careers as researchers since the early 50’s, a period which saw post-war France rebuild its capability in physics
around large-scale instruments. E. Brézin recalls some of science’s most recent advances, and how their applications
have changed our way of life. He stresses too some major unresolved problems.
J. Friedel, on graduating from Ecole Polytechnique, France’s leading engineering institute, went to Bristol University
where he spent three years studying with Nevill Mott, a future Nobel laureate, preparing a Ph.D. on the electronic
structure of metallic alloys. Returning to France, he was appointed in 1956 Professor at Paris-Orsay University where
he set up the Solid State Physics laboratory, which another future Nobel laureate, Pierre-Gilles de Gennes, joined in
1961. In the mid 50’s he was appointed to the CNRS subject committee on Electronics. His experience there led
him to recommend that the CNRS redefine its subject committees, not according to physical phenomena and the
associated instrumentation but according to the materials studied : solid state physics was one of those committees,
which he chaired from 1968 onwards. During the 70’s and 80’s he was very much involved in developing university
research with the fullest CNRS support. From the 80’s onwards however, a tripling of student numbers, with
no matching increase of teaching resources meant that within the mixed CNRS/university research teams an increasing
proportion of the research effort was borne by the CNRS. This imbalance, he stresses, has to be redressed.
Major reforms of the universities and the CNRS currently under way are addressing this issue.
M. Petit on graduating, like J. Friedel from Ecole Polytechnique, joined France’s National Centre of Telecommunications
Research in 1960 in order to pursue a research career. This was the beginning of space research and M. Petit was immediately
involved in designing and building instruments aimed at studying radioelectronic waves in the ionosphere, with a
view to improving telecommunications in space. He obtained a geophysics Ph.D. on the subject in 1967 and went on to
design instruments for telecom satellites which were installed in the European Space Agency’s satellite GEOS, launched in
the early 70’s and later in NASA satellites.
In 1978 he was appointed Scientific Director of CNRS’s department of Earth, Ocean, Atmospheric and Space
sciences, where he was involved in major international collaborative ventures developing and managing large-scale
instruments : the large telescope in Hawai, the millimetric radio wave telescopes at Bure in France and Pico Veleta
in Spain, Europe’s EISCAT facility with Scandinavian cooperation. He held various positions in Brussels and Paris between
1985 and 1994 advising or managing international cooperative ventures in space research. In 1992 he was
appointed French representative to the executive board of IPCC (International Panel on Climate Change), set up
under the Kyoto protocol to monitor climate change. He held that post until 2002. Simultaneously, from 1994 to
2000 he was Director of Research at Ecole Polytechnique, where he was instrumental in strongly developing research
in partnership with the CNRS and major high tech firms on the Ecole Polytechnique campus. A major purpose of
this initiative was to encourage a larger number of engineering students at Polytechnique and in other « Grandes
Ecoles » to start their careers in research through a Ph.D. so as to strengthen the continuum between basic academic
research and its industrial applications.
E. Brézin’s paper, starting with Darwin and Wegener, focuses on the evolution of scientific knowledge through the
constant reappraisal of current theories in the light of new observations obtained through more advanced instruments.
Thus Hubble’s observations in 1921, that the universe is expanding, forced Einstein to revise his general relativity
theory based on the assumption that the universe is static. Brézin goes on to show that without Einstein’s findings
on the relativity of time, the GPS could never have been designed.
In its 125th anniversary issue in July 2005, « Science », the journal of the American Association for the
Advancement of Science, listed 125 unresolved problems. Some have since then been resolved such as « Poincaré’s
conjecture on S3 », by the young Russian mathematician, G. Perelman.
Many others remain unresolved, one of the most intractable issues being that of conscience or self-awareness. Until
now, this issue has been the prerogative of philosophers. Could it be addressed as a scientific problem, i.e. to be
resolved by combining an experimental approach and rational argument ?
Unresolved issues in physics include such questions as reconciling gravitation and quantum mechanics, or asking
whether the values of the constants of nature (the speed of light, Newton’s constant, Planck’s constant…) are
haphasard or whether they are the outcome of a basic principle which we are unable to identify ?
Another problem, symbolized by the acronym LUCA (Last Universal Common Ancestor) is whether life originated in
a single molecule which reproduced itself then became diversified and increasingly complex, or whether it evolved
through alternative mechanisms ?
Brézin’s conclusion is that « we, phycisists, believe that we can barely identify half of the particles that make up the
universe ». The Large Hadron Collider at CERN should enable us to answer some of our queries. There are clearly
plenty of opportunities for to-day’s and tomorrow’s young scientists.
The three papers highlight the importance of the development of ever more sophisticated instruments as a pre-requisite of
the advancement of science. They also stress the close links between basic science and high tech industry, as well as the key
contribution of the CNRS to the whole of France’s research capability during the past 60 years.