Researchers at the National Ignition Facility want to do nothing less than create a star on earth. The nuclear fusion facility in Livermore, California has been under construction since 1997, but now engineers are finally ready to fire up the facility's 192 lasers, and to generate the nuclear reaction present only inside the cores of stars and exploding thermonuclear weapons. At NIF, that reaction will take place inside this tiny gold cylinder, which is the size of a pencil eraser.