Suppose three stars lie in the disk of the galaxy at distances of 20,000 light-years, 25,000 light-years, and 30,000 light-years from the galactic center, and suppose that right now all three are lined up in such a way that it is possible to draw a straight line through them and on to the center of the galaxy. how will the relative positions of these three stars change with time? assume that their orbits are all circular and lie in the plane of the disk.