2 00 2 Dark matter , dark charge , and the fractal structure of the Universe

It is shown that the observed fractal distribution of galaxies is, in fact, consistent with homogeneity of the Universe and observational limits on ∆T /T , if the presence of dark matter and dark charge predicted by the Modified Field Theory is taken into account. It is discussed a new scenario of structure formation in which observed structures appear as a result of decay of the primordial fractal distribution of baryons. As it was shown (e.g., see Ref. [1, 2] and for a more recent discussions Ref. [3, 4, 5]) observed galaxy distribution exhibits a fractal behaviour with dimension D ≈ 2 and which seems to show no evidence of cross-over to homogeneity. In spite the fact that the picture in which baryons have a fractal distribution in space is not widely accepted, it, in fact, has recently found a rigorous theoretical ground. First, we note that there are two basic arguments which do not allow to accept such a picture. The first argument is that the fractal distribution can be in a conflict with the Cosmological Principle which is expressed by the statement that the metric of the universe is well approximated by the Friedmann metric and, therefore, gravitational potential fluctuations must be small. Such metric potential fluctuations are measured directly by ∆T /T in the microwave background and as it was discussed in Ref. [6] the density distribution does not give direct evidence of the " Cosmological principle ". However, if we suppose that the Universe does not contain some hidden component of matter and all baryons are described by a fractal distribution in space, this should result in too strong metric fluctuations and too strong ∆T /T , whereas there exist strong observational limits ∆T /T < 10 −5. We stress that if the leading contribution to the matter density is given by a dark component then metric fluctuations are not directly related to the distribution of baryons and can remain small. However, there exists another argument which does not depend on the presence of dark matter and can be considered independently. It is the Silk effect which directly relates the distribution of baryons at the moment of recombination with variation of the CMB temperature n b ∼ T 3 and, therefore, the fractal distribution of baryons must leave a direct imprint in the temperature. It turns out that these problems can be easily solved in the …