Lockheed Martin announced yesterday that it has made what Reuters calls a "technological breakthrough" in the area of compact nuclear fusion. The upshot is that reactors "small enough to fit on the back of a truck" could be here within 10 years. As Forbes explains, nuclear fusion combines two atoms into one, creating as much as quadruple the energy as nuclear fission (when an atom is split in two), and it does so without producing radiation. Project head Tom McGuire says Lockheed has been working on its compact fusion concept secretly for four years, but it's now looking for industry and government partners. "The smaller size will allow us to design, build, and test the compact fusion reactor in less than a year," says McGuire, with a prototype coming in five years. But some are skeptical: