The Merger of the Schwarzschild metric and the Robertson-Walker metric
  The Schwarzschild metric giving the space time due to a spherically symmetric object is derived in the background of the Robertson Walker metric. In other words the two metrics are merged. It is found that under certain conditions the merger is at a distance less than the radius of the spherically symmetric object, thus not separating the object from the rest of the universe. 
Bethmini Senevirathne (Department of Physics and Astronomy, University   of Glasgow, UK) and Nalin de Silva (Department of M...