The Milky Way is the galaxy that contains the Solar System. It is a barred spiral galaxy 100,000-120,000 light years in diameter containing 200–600 billion stars. The galaxy is estimated to contain 50 billion planets, 500 million of which could be located in the habitable zone of their parent star. The rotational rate: 1 per 15 to 50 million years. The galaxy is also moving at … [Read more...]