According to the standard model of cosmology, the vast majority of galaxies are surrounded by a halo of dark matter particles. This halo is invisible, but its mass exerts a strong gravitational pull on galaxies in the vicinity. A new study challenges this view of the Universe. The results suggest that the dwarf galaxies of Earth’s second closest galaxy cluster known as the Fornax Cluster are free of such dark matter halos. The Fornax Cluster has a rich population of dwarf galaxies. Recent observations show that some of these dwarfs appear distorted, as if they have been perturbed by the cluster environment. The authors analysed the expected level of disturbance of the dwarfs, which depends on their internal properties and their distance to the gravitationally powerful cluster centre. Galaxies with large sizes but low stellar masses and galaxies close to the cluster centre are more easily disturbed or destroyed. They compared the results with their observed level of disturbance evident from photographs taken by the VLT Survey Telescope of the European Southern Observatory.