An artist’s illustration shows streams of stars pulled from a companion galaxy circling the Milky Way. Similar streams originating from the Sagittarius dwarf galaxy can help reveal the shape of dark matter in our cosmic vicinity.
By Adam MannThe Milky Way hasn’t been kind to the Sagittarius dwarf galaxy. Located some 70,000 light-years away, the bundle of stars has been shredded and stretched into a filamentous stream by the gravity of the Milky Way.
Now, scientists have mapped Sagittarius in exquisite detail, and they’ve used that map to provide a long-sought picture of the mysterious dark matter halo in which our Galaxy resides.First spotted in 1994, Sagittarius is one of the Milky Way’s closest companions.