IL FLEBILE SUSSURRO DEL CAOS NELL’ARMONIA DEI PIANETI

Abstract

The hystorical development of the problem of stability of the Solar System is revisited, starting fromthe work of Kepler. The following topics are included: (i) the discovery of the so called ‘‘great inequality’’ of Jupiter and Saturn by Kepler himself; (ii) the dawn of perturbation theory in the work of Lagrange and Laplace and the problem of resonances; (iii) the discovery of chaotic motions in the work of Poincar´e; (iv) the theorem of Kolmogorov on persistence of quasi periodic motions and the theory of Nekhoroshev on stability over exponentially long times. Finally, an account is given concerning some recent work on the actual applicability of the theorems of Kolmogorov and Nekhoroshev to realistic models of the Solar System, thus pointing out their relevance in discussing the problem of stability.