Hubble Observations Suggest a Missing Ingredient in Dark Matter Theories

Astronomers using Hubble and the VLT have found that something may be missing from the theories of how dark matter behaves. This missing ingredient may explain why they have uncovered an unexpected discrepancy between observations of the dark matter concentrations in a sample of massive galaxy clusters and theoretical computer simulations of how dark matter should be distributed in clusters. The new findings indicate that small-scale concentrations of dark matter produce lensing effects that are 10 times stronger than expected.