Cosmological Principle and Relativity - Part I

The absence of an identified consequence at solar system scale of the cosmological space expansion is usually explained considering that space expansion does not affect local anysotropies in matter distribution. This can also be explained considering a time dependent scenario compatible with Relativity Principle, therefore supporting physical laws independent of the time position of the observer. A theory considering such relativist scenario, i.e., generalizing Relativity Principle to position, embodies Cosmological Principle and can be intrinsically able to fit directly both local and cosmic data. In part I it is presented the general framework of such a theory, called Local Relativity (LR), and analysed the space-time structure. Special Relativity space-time is obtained, with no formal conflict with Einstein analysis, but fully solving apparent paradoxes and conceptual difficulties, including the simultaneity concept and the long discussed Sagnac effect. In part II, LR is applied to positional analysis. It is verified the accordance with solar system measurements and with classic cosmic tests, without dark matter or dark energy. Two of the new features obtained in part II are the possibility of a planetary orbital evolution compatible with a null determination for G variation, supporting a warmer scenario for earth (and Mars) past climate, and the possibility of an accelerating component in earth rotation, compatible with the most recent measurements.