A closer look

Physicists realized early on that you don't need the fury of a sun to fuse atoms. You just need fatter electrons. By replacing an electron in a hydrogen molecule with a muon—a subatomic particle 200 times heavier—the nuclei are pulled so ridiculously close together that they spontaneously fuse at room temperature. It is literally cold fusion that actually works, unlike the debunked 1980s junk science, though muons currently decay too quickly to power your house.