Rotation Curves of Spiral Galaxies

Rotation curves of spiral galaxies is an old problem. It was one strong evidence supporting the presence of Dark Matter in the Universe. The problem is certainly not simple, but the solution may be found to be very simple. Recently an article by M.B. Altaie and N.R. Sulaiman has been posted at arXive. org shows that the rotation curves of spiral galaxies might be produced by the effect of an emergent viscosity without the need to assume the presence of dark matter. A pre-print is available at  at https://arxiv.org/ftp/arxiv/papers/1802/1802.01163.pdf