re: More arguements
As the universe ages, galaxies might get larger. The area of the galactic disks would increase with the square of the radius:
Area = pi * R^2
So if the mean radius of a random sample of galaxies varies directly with time, via some proportionality constant, then we have the following equation:
R = k * t
and we can substitute the above equation into the kinetic energy equation derived previously:
KE = 0.5 * m * (a * k * R)^2