During the last few decades, it has been discovered that most of the material in the Universe is invisible. Since it interacts only gravitationally with the rest of the Universe components. From the latest measurements of WMAP satellite we know that the Universe consists of 4% Baryons, 22% Cold Dark Matter, 74% Dark Energy. Now it is clear a wonderful time to study cosmology. Using the latest technological advances we have obtained detailed picture of the early Universe and maps of the distribution of matter on the largest scales in the Universe today. And we have a physical model for the origin and evolution of the Universe. However on the small scales there are still a lot of open issues. The mass distribution in spiral galaxies is an interesting question that is tightly band to the galaxy formation and evolution process.
