Some observable effects in relativistic cosmology with non-perfect fluids

We consider non-perfect fluid distributions as sources of Friedmann-Robertson-Walter geometries. This allows anisotropies on the temperature of the cosmic background radiation, with a dipole component that can be used, under physically reasonable assumptions, to obtain that nepsilon(0,1/2) if we assume a matter flow with behavior u2proportionalR-/sup n/[R(t) is the scale factor], taking into account that the velocity of Earth with respect to any observer that sees that radiation isotropically is (plausibly) ν0> or approx. =100 km s-1. In the case of a flat geometry, we obtain the conditions satisfied by a homogeneous velocity field in order to have viscous and heat conduction terms, and we give different values and upper limits on the shear-viscosity coefficient, the relative shear, and the relative acceleration