  In this brief note we aim to provide, through a well known class of singular
densities in harmonic analysis, a simple approach to the fact that the
homogeneity of the universe on scales of the order of a hundred millions light
years is completely compatible with the fine-scale condensation of matter and
energy. We give precise and quantitative definitions of homogeneity and
isotropy on large scales. Then we show that Muckenhoupt densities have the
ingredients required to a model for the large-scale homogeneity and the
fine-scale condensation of the universe. In particular, these densities can
take locally infinitely large values (black holes) and at once, in the large
scales they are independent of the location. We also show some locally singular
densities satisfying the large scale isotropy property.
