For decades, scientists have puzzled over why galaxies spin faster than expected. The stars in their outer regions move so quickly that, by the laws of physics, they should fly apart. Something unseen-something massive-seems to be holding them together. This invisible force has long been attributed to dark matter, a mysterious substance that makes up [.] The post Tiny dwarf galaxies help solve a 40-year dark matter debate appeared first on Knowridge Science Report.