- A galactic smashup might explain galaxies without dark matter. About 8 billion years ago, researchers propose, two dwarf galaxies slammed into one another. That cosmic crash caused the gas within those 2 galaxies to split up & form multiple new dwarf galaxies, including the two dark matter–free ones https://www.sciencenews.org/article/galaxy-dark-matter-dwarf-galaxies-physics-space 6 comments science