The Lumpy Universe
Scientists believe that the lumpiness of the universe may have occurred as a result of quantum fluctuations during the inflationary period of the big bang. A Big Bang Observer mission that views gravitational waves would be required to test the extent of these fluctuations, but right now it would be very difficult and costly to build. One upcoming mission, LISA, is a big step in this direction. It is expected to reveal of information about black hole formation and other gravitational phenomena in our universe.