Hubble spots galaxy made almost entirely of dark matter
Astronomers using the Hubble Space Telescope, Euclid, and the Subaru Telescope have identified Candidate Dark Galaxy-2 (CDG-2) in the Perseus Cluster, a galaxy so faint it’s dominated by dark matter—at least 99.9%—with four globular clusters indicating a massive dark halo and little to no starlight. The finding, based on globular clusters around a largely starless galaxy, suggests such dark galaxies may be common and could provide clean tests of dark matter physics; further observations with the James Webb Space Telescope could help confirm its dark matter content.
