So what is a supersolid? Like a solid, it has a rigid structure, but like a superfluid, it has zero viscosity and never loses kinetic energy. Once thought to be impossible, physicists believed that it was possible to create a supersolid by taking solid helium and agitating the motion of helium atoms within the crystal. The existence of such a substance was postulated in the 1970s, and, if realized, could be used in extremely powerful superconducting magnets and sensors, as well as energy transportation.