Dysprosium and terbium. They mean nothing to most people. But without them, an F-35 can't fly. They're in flight control actuators, guidance fin motors, the radar magnets. A single F-35 contains 920 pounds of rare earths. A Virginia-class submarine, 9,200 pounds. An Arleigh Burke destroyer, 5,200 pounds. They're in Tomahawks, Sidewinders, Patriots, Stingers. Every precision-guided weapon in the U.S. arsenal.