ABSTRACT
One of the great scientific mysteries still unsolved is the existence of DM. Most astronomers, cosmologists and particle physicists are convinced that at least 26.8% of the mass of the Universe is constituted by some matter of non-luminous form, called DM. Although the existence of DM was suggested 68 years ago, we still do not know its composition. Despite the fact that the nature of this DM is still unknown, its hypothetical existence is not so odd if we remember that the discovery of Neptune in 1846 by Galle was due to the suggestion of Le Verrier on the basis of the irregular motion of Uranus.
