Astronomers discover galaxy made of 99% dark matter - CNN

Astronomers have identified an ultra-diffuse galaxy about 300 million light-years away that appears to be roughly 99% dark matter, with visible stars making up only a tiny fraction of its mass. The contrast between such dark-matter-dominated systems and local remnant debris like the Milky Way's "Loki" highlights the variety of outcomes from galaxy formation and interactions. Comparing these extremes helps researchers test how dark matter and environmental effects influence whether a system retains or loses its stars, refining models of galaxy formation.