  Stretching of the Newtonian potential (NP) at early epochs is investigated
and it is shown that observed effects, usually ascribed to a dark matter, can
by explained by such stretching only. Increasing by time radius of the
gravitationally-bound region (GBR) and conservation of gravitational energy
lead to a new scenario in which values of NP in expanding volume are
maintained, while in physical volume are stretched. Really, the energy
conservation in expanding volume requires for NP values to be comoving to the
expanding shells. In addition, the radius of gravitationally-bound region
increases by time due to decreasing of expansion velocity and different shells
around galaxy cease expansion at different times. Thus, as far a shell placed
from galaxy, as longer it was expanded and thickened, while potential
difference on its boundaries remained unchanged. This shifts the values of NP
around galaxy proportional to the distance r and, as the result, the
gravitational acceleration, from NP's $1/r^2$ dependence, turned to 1/r
dependence, as for centrifugal acceleration. This fact naturally explains the
known empirical facts, such as flatness of rotation curves and velocity-mass
relationships for galaxies and velocity dispersion in clusters.

General Physics