The nature of space-time is confronted with the experiment today. The spatial environment opens new possibilities of testing the theory of relativity and the alternative theories, to unify the gravitation with the other fundamental interactions which are described in a quantum way.
The theme includes in particular:
- the direct detection and the analysis of the gravitational waves,
- the tests of the equivalence principle of Einstein (including the variation of the fundamental constants and the gravitational gap of the frequencies),
- the measure of the Post-Newtoniens parameters.
These activities require new spatial instruments such as clocks, links of transfer of time, inertial senseurs, optical interferometers or in waves of matter.