Gravitational structure formation in scale relativity∗

In the framework of the theory of scale relativity, we suggest a solution to the cosmological problem of the formation and evolution of gravitational structures on many scales. This approach is based on the giving up of the hypothesis of differentiability of space-time coordinates. As a consequence of this generalization, space-time is not only curved, but also fractal. In analogy with Einstein’s general relativistic methods, we describe the effects of space fractality on motion by the construction of a covariant derivative. The principle of equivalence allows us to write the equation of dynamics as a geodesics equation that takes the form of the equation of free Galilean motion. Then, after a change of variables, this equation can be integrated in terms of a gravitational Schrödinger equation that involves a new fundamental gravitational coupling constant, αg = w0/c. Its solutions give probability densities that quantitatively describe precise morphologies in the position space and in the velocity space. Finally the theoretical predictions are successfully checked by a comparison with observational data: we find that matter is self-organized in accordance with the solutions of the gravitational Schrödinger equation on the basis of the universal constant w0 = 144.7± 0.7 km/s (and its multiples and sub-multiples), from the scale of our Earth and the Solar System to large scale structures of the Universe. c ©2002 Elsevier Science Ltd. All rights reserved.