it is equivalent formulations - the point masses case is obtained from the spherical in the limit. The spherical case is just more illustrative to show where th

it is equivalent formulations - the point masses case is obtained from the spherical in the limit. The spherical case is just more illustrative to show where the fantom of the "dark matter" in the disk galaxies comes from. >by integrating a mass density over a region. exactly. When you do that for a disk galaxy you get much flatter curves that the 1/R the proponents of the dark matter insist on (that 1/R is exactly what one would get if the galaxy was spherical or the star was far outside of the disk)