(3) Mass density
The average mass density in the universe is based on Virial mass, because comic mass refer to the mass of gravitational matter, but the property of gravitational matter is aggregation and obeying classical mechanics. Thus, it is impossible, outside the galaxy, to find matter which mass is much greater than the galaxy
The density according to a galaxy count and mass-luminosity relation is calculated at
this is universally acknowledged.
It has been calculated from coma that Virial mass is 8.3 times as great as optical mass. Therefore I adopt
Formula of overage mass density is