A cosmological model , in which the cosmic microwave background ( CMB ) is a thermal radiation of intergalactic dust instead of a relic radiation of the Big Bang , is revived and revisited .
The model suggests that a virtually transparent local Universe becomes considerably opaque at redshifts z > 2 - 3 .
Such opacity is hardly to be detected in the Type Ia supernova data , but confirmed using quasar data .
The opacity steeply increases with redshift because of a high proper density of intergalactic dust in the previous epochs .
The temperature of intergalactic dust increases as ( 1 + z ) and exactly compensates the change of wavelengths due to redshift , so that the dust radiation looks apparently like the radiation of the blackbody with a single temperature .
The predicted dust temperature is T ^ { D } = 2.776 \mathrm { K } , which differs from the CMB temperature by 1.9 % only , and the predicted ratio between the total CMB and EBL intensities is 13.4 which is close to 12.5 obtained from observations .
The CMB temperature fluctuations are caused by EBL fluctuations produced by galaxy clusters and voids in the Universe .
The polarization anomalies of the CMB correlated with temperature anisotropies are caused by the polarized thermal emission of needle-shaped conducting dust grains aligned by large-scale magnetic fields around clusters and voids .
A strong decline of the luminosity density for z > 4 is interpreted as the result of high opacity of the Universe rather than of a decline of the global stellar mass density at high redshifts .