Little Perturbations Grow up...Without Dark Matter

One of the main problems of Cosmology is to conciliate the initial homogeneity and isotropy of the Universe with the subsequent formation of galaxies. In order to find a solution, the Cosmic Microwave Radiation was deeply investigated and a very small anisotropy was finally detected and indicated as the cause of the structure formation. In the standard cosmological theory it is often demonstrated that the linear perturbations do not evolve in a way able to explain the large scale structure of the today observed Universe. In our paper we want to give a simple counterexample showing that it would be possible the formation of a clustered structure in the Universe without the help of the existence of Dark Matter.