"For the Milky Way, we find that the orbital speed increases and then remains roughly constant. This implies that we are still within the body of the Milky Way, even at the largest distances from the center of the Milky Way. We have not yet located the edge of the Milky Way; the Milky Way extends much further than the edge of the disk of stars (the visible disk)! The mass contained in the Milky Way (in the visible disk) is 2x1011 M(Sun). The mass contained in the Milky Way galaxy (out to as far as we can see HI gas) is 6x1011 M(Sun)."