The Milky Way contains 100-400 billion stars and is estimated to have at least 50 billion planets, 500 million of which could be located in the habitable zone of their parent star.New data suggests there may be up to twice as many free-floating planets in the Milky Way as there are stars. The Milky Way is part of the Local Group of galaxies and is one of around 200 billion galaxies in the observable universe.