Astronomers have spotted the faintest and lightest satellite galaxy ever found: a minuscule, tight-knit group of stars trailing the Milky Way. The peculiar discovery could represent a new class of impossibly faint, dark-matter-dominated star systems that had eluded detection until now.
Tentatively named Ursa Major III/Unions 1 (UMa3/U1), the newfound star system resides in the constellation Ursa Major, about 30,000 light-years from the sun. It is the newest addition to our galaxy's assortment of at least 50 satellite galaxies. Even the smallest of these galaxies host thousands to billions of stars.
