The issue focused on two studies of dark matter in the cluster SDSS J1245+2545, which were published in March and June of this year. The study in March by researchers at the University of California, Santa Cruz, and the University of Michigan used the NASA/ESA Hubble Space Telescope to study the evolution of the massive particles in the cluster. The study in June by researchers at the University of Chicago and the University of Michigan used the NASA/ESA Hubble Space Telescope to study the evolution of the