WHAT DO WE MEAN BY "FUNDAMENTAL PHYSICS IN SPACE"?

Fundamental physics in space, as defined by the Committee on Space Research (COSPAR), covers research activities which may be classified into two closely correlated categories, (1) the study of fundamental laws governing matter, space and time, and (2) the use of Space to investigate the principles governing the structure and complexity of matter.
CNES contributes to the effort to understand these laws through the French scientific community, within ESA or in co-operation with other Space agencies. Since the CNES prospective seminar held in St Malo in October 1993, the French scientific community has suggested several Space experiments in fundamental physics and has proven its competence in this international field, involving technological innovation and theoretical research. The scientists work within the "Gravitation and Experiment in Space" Group (GDR GREX) created by the CNRS in 1995 and financed by CNES.

MATTER, SPACE AND TIME

During the first half of the 20th century, two important theories, the theory of general relativity and the quantum theory, considerably changed our perception of our physical world. On the basis of these two theories, physicists working in the second half of the 20th century, developed and tested a new theory of matter, called the Standard Model and extended the classical theory of Space-Time (the "Big Bang" cosmology theory).
Questions as fundamental as the ultimate laws governing our physical reality and the origins and physical content of our universe, can now be formulated and studied: answers may even be found. Is there a "unified theory" which covers all physical laws? Is matter fundamentally unstable? Are there other spatial dimensions? Is most of the mass of the universe hidden, in an as yet unknown form? Does the Space "vacuum" have energy in it?
Physicists and astronomers are beginning to find answers, based on scientific hypotheses, which can be tested by suitable experiments and observations.
Section (1) thus includes (but is not limited to):

gravitational physics and particle physics related to tests of general relativity and alternate theories,
the investigation of gravitational waves in Space,
research into particles and anti-matter in Space,
the investigation of possible violations of the Equivalence Principle,
the search for possible drifting of fundamental constants,
the search for possible new fundamental "forces",
the unification of fundamental interactions of nature.

THE USE OF SPACE FOR STUDYING THE PRINCIPLES GOVERNING THE STRUCTURE AND COMPLEXITY OF MATTER

Given the prodigious breakthroughs of science and techniques during the 19th century, the French chemist, Marcellin Berthelot, is said to have exclaimed: "there are no problems which science cannot solve". Lord Kelvin (whose name was used for a unit of temperature) also said at the end of the 19th century that physics was finished, that everything had been understood, that our theories worked so well that they could not be wrong, but that there were perhaps two small clouds in the blue sky (in fact these small clouds were to lead to the theories of relativity and quantum physics!!!).
Likewise, inaugurating his lectures on physics, delivered in Cambridge in 1871, James Clerk Maxwell announced that within a few years "scientists would spend their time adding a few decimals to the major physical constants".
Thirty years later, however, Max Planck, with his equation for the black body spectrum, created the first shock wave in the quantum revolution. After more than 100 years of quantum physics and in spite of the success of this theory, experience has shown that the Universe is even stranger than we might think.

Section (2) thus, covers (but is not limited to):

quantum physics and its applications, for instance, the Bose-Einstein condensate, and the study of critical phenomena in superfluids,
the application of laser-cooled atoms for developing new types of clocks or inertial sensors using atomic interferometry,
The role of symmetry principles in macroscopic physics.

We have reached a very significant stage in our understanding of our universe and of the physical laws which govern it. It now appears that the questions being investigated by scientists concerning our universe and its two extremes, the infinitely small and the infinitely large, are closely related. Space has now become an indispensable environment for undertaking extremely sensitive experiments which have never been conducted and which cannot be conducted on Earth. Indeed, in the years to come, new ideas on the nature of space-time, the possibility of other dimensions, the nature of "dark matter" and "dark energy", which appear to be the main constituents of the universe, should be experimentally tested. The new theories have predicted minute effects which violate general relativity and it should be possible to observe these. Teams of French scientists, led by CNES, are consequently preparing several Space experiments. These are based on innovative technology for measuring time, distances and accelerations. For almost 10 years, CNES has devoted a lot of effort to developing cooled atomic clocks, laser telemetry, electrostatic accelerometers and cold-atom inertial sensors, which will be the technological building blocks of future experiments for testing the most fundamental laws of physics.