Physicists spent years growing delicate thorium-229 crystals for nuclear clocks — milligrams of one of Earth's rarest isotopes.
New approach: electroplate thorium onto steel. Same trick jewelers use to gold-plate rings. 1000x less material. Published in Nature.
Nuclear clocks tick inside the nucleus, not electron shells — orders of magnitude more precise. Could work where GPS fails: underwater, deep space.
The breakthrough was remembering an old technique.