The space is not void as there is non-zero density of matter that we see in absorbtion lines of quasars [1]. This implies that the space has to be treated as tr

The space is not void as there is non-zero density of matter that we see in absorbtion lines of quasars [1]. This implies that the space has to be treated as transparent medium with non-trivial optical properties. [1] - https://ned.ipac.caltech.edu/level5/Madau6/Madau_contents.html https://ned.ipac.caltech.edu/level5/Madau6/Madau_contents.ht...