Discretization on the cosmic scale inspired from the Old Quantum Mechanics

The Old Quantum Mechanics actions discretization rules for periodic motions on the atomic scale (Bohr-Sommerfeld) have been suitably modified in order to account the gravitational field instead of the electrostatic one. The new rules are used to calculate a few mechanical quantities pertinent to the periodic motions of celestial bodies. Several values have been obtained which result in reasonable agreement with the corresponding experimental data. A gravitational dimensionless structure constant has been determined, using the data relative to the solar sistem, which allows to quantitatively account for phenomena on a much wider scale. In particular, some information is acquired about the recently discovered extrasolar planetary systems and about the general empirical law which connects the spin of a celestial body with the square of its mass.