Milky Way's spiral arms are the product of an intergalactic collision course; Models show dark matter packs a punch
Wednesday, September 14, 2011 - 14:30
in Astronomy & Space
Astronomers have shown how the Milky Way galaxy's iconic spiral arms form, according to new research. A dwarf galaxy named Sagittarius loaded with dark matter has careened twice through our much larger home galaxy in the past two billion years, according to telescope data and detailed simulations, and is lined up to do it again. As the galaxies collide, the force of the impact sends stars streaming from both in long loops.