A study by Moore et al. (1998) shows that the cold dark matter (CDM) model fails to reproduce the rotation curves of dark matter-dominated galaxies, a key issue it was designed to solve. High-resolution simulations of dark matter halos, each containing more than 10^6 particles and resolved to 0.003 times the virial radius, show that the density profile ρ(r) ∝ [ (r/r_s)^1.5 (1 + (r/r_s)^1.5) ]^{-1} fits both galactic and cluster-sized halos well. This profile has a steeper asymptotic slope and sharper turnover than lower-resolution studies. The central structure of relaxed halos has a small scatter, and relaxed halos do not host disks. Comparing with low surface brightness (LSB) galaxies with circular velocities between 100-300 km/s, the rotation curves of disks in CDM halos rise too steeply to match these data, which require a constant mass density in the central regions. The same conclusion is reached when comparing the scale-free shape of observed rotation curves with simulation data. It is important to confirm these results using stellar rather than HI rotation curves for LSB galaxies. The study also tests the effects of introducing a cutoff in the power spectrum, which may occur in a warm dark matter universe. In this case, halos form via monolithic collapse, but the final density profile does not change, showing that the merger history does not affect the halo structure. The results suggest that the CDM model cannot explain the observed rotation curves of LSB galaxies, and that the dark matter in galactic halos is not a cold collisionless particle. The study concludes that the CDM model needs a new physical process to explain the observed constant density cores in LSB galaxies. The results should be confirmed using stellar velocities of LSB disk stars.A study by Moore et al. (1998) shows that the cold dark matter (CDM) model fails to reproduce the rotation curves of dark matter-dominated galaxies, a key issue it was designed to solve. High-resolution simulations of dark matter halos, each containing more than 10^6 particles and resolved to 0.003 times the virial radius, show that the density profile ρ(r) ∝ [ (r/r_s)^1.5 (1 + (r/r_s)^1.5) ]^{-1} fits both galactic and cluster-sized halos well. This profile has a steeper asymptotic slope and sharper turnover than lower-resolution studies. The central structure of relaxed halos has a small scatter, and relaxed halos do not host disks. Comparing with low surface brightness (LSB) galaxies with circular velocities between 100-300 km/s, the rotation curves of disks in CDM halos rise too steeply to match these data, which require a constant mass density in the central regions. The same conclusion is reached when comparing the scale-free shape of observed rotation curves with simulation data. It is important to confirm these results using stellar rather than HI rotation curves for LSB galaxies. The study also tests the effects of introducing a cutoff in the power spectrum, which may occur in a warm dark matter universe. In this case, halos form via monolithic collapse, but the final density profile does not change, showing that the merger history does not affect the halo structure. The results suggest that the CDM model cannot explain the observed rotation curves of LSB galaxies, and that the dark matter in galactic halos is not a cold collisionless particle. The study concludes that the CDM model needs a new physical process to explain the observed constant density cores in LSB galaxies. The results should be confirmed using stellar velocities of LSB disk stars.