Map of Milky Way's halo sheds light on dark matter 'ocean'
Astronomers have released a new map of the outermost region of our galaxy. Known as a galactic halo, this area lies outside the swirling spiral arms that make up the Milky Way’s recognizable central disk, and is sparsely populated with stars. Though the halo may appear mostly empty, scientists predict it contains a massive reservoir of dark matter, an invisible material thought to make up the bulk of all mass in the universe. The new map, which appears as part of a paper in Nature, reveals how a small galaxy called the Large Magellanic Cloud—so-named because it is the larger of two dwarf...