In the latest episode the Science Channel's Sci Fi Science, Dr. Michio Kaku reveals his plans on how to build a real, working planet destroying laser. In nerd speak, a Death Star.

Summary from Science Channel episode guide:

The crosshairs are lined up, a death ray is fired and a planet is vaporized. Sci fi fantasy? Not according to Dr Michio Kaku, who draws up blueprints to show how a real death star might work. The technology could be here sooner than you think!