According to the theory of relativity, the universe should expand from the center (place of Big Bang) with a maximum possible radial speed close to the speed of light c. So, the galaxies and intergalactic matter moves with a radial speed close to the speed of light too. For instance, this allows to introduce an interesting new idea for the interpretation of the missing mass, dark matter, and dark energy. The current assumption is that the universe contains 4.9% of baryonic matter, 26.8% of dark matter, and 68.2% of dark energy. However, if galaxies and intergalactic matter are moving with the speeds close to c, we should take into account the increase of the mass or energy due to this relativistic speed. The mass which we are observing is related to rest mass m0 and the energy corresponds to peculiar velocities. However, in the models to calculate, for instance, critical density, we should take into account mass increase due to the motion of the baryonic matter mrel = m0/√1/(1-v2/c2). To account for the 95.1% of the missing density, galaxies and intergalactic matter should have speed approximately equal to 99.9% of the speed of light.