Vienna's new clock loses a second every 30 million years — and steadies itself

Thorsten Schumm's team at TU Wien has built the world's first self-stabilising nuclear clock. Ordinary atomic clocks time the wobble of electrons; this one times a jump inside the nucleus of thorium atoms, which are more than 10,000 times smaller and far harder for the outside world to disturb. The trick is a feedback loop: a laser excites the thorium in a special crystal, and if the laser drifts even slightly, the crystal absorbs less light — a signal the system uses to pull itself back on beat, unaided, for more than 24 hours. Its measured precision is already about one second of error in 30 million years. It is a first prototype, not yet a match for the best optical clocks — but it now keeps its own time.

SDG 9 · Industry, innovation and infrastructure — Mechanism: tech innovation