A research team released an unprecedentedly wide and sharp dark matter map based on the newly obtained imaging data by Hyper Suprime-Cam on the Subaru Telescope. The dark matter distribution is estimated by the weak gravitational lensing technique. The team found indications that the number of dark matter halos could be inconsistent with what the simplest cosmological model suggests. This could be a new clue to understanding why the expansion of the universe is accelerating.