Figure 3: The points show the observed 21 cm line rotation curves of a low surface brightness galaxy, NGC 1560 [9] and a high surface brightness galaxy, NGC 2903 [10]. The dotted and dashed lines are the Newtonian rotation curves of the visible and gaseous components of the disk and the solid line is the MOND rotation curve with  cm/s2—the value derived from the rotation curves of 10 nearby galaxies [12]. Here the only free parameter is the mass-to-light ratio of the visible component.