California scientists may have discovered a source of unlimited clean energy by recreating the process of nuclear fusion which powers the sun. Researchers at the National Ignition Facility at the Lawrence Livermore National Lab in Livermore were able to spark a fusion reaction that briefly sustained itself - a major feat because fusion requires such high temperatures and pressures that it easily fizzles out. The experiment was performed in August, but reported for the first time earlier this month. Similar tests have been performed before, but this was the first one that generated more energy than was used to create...