Most of us can't even keep the microwave clock right after a power cut. Physicists in Vienna just built a nuclear clock that adjusts itself and kept running for over a day without anyone touching it. Somewhere, a Swiss watchmaker is quietly reconsidering their career.
Thorium Steps Up as Timekeeper
Researchers at TU Wien's Institute of Atomic and Subatomic Physics, working with Germany's PTB Braunschweig, have built the world's first prototype of a self-stabilizing nuclear clock, published in Nature on October 7. It's built around a thorium crystal stimulated by a laser, and it ran on its own for more than 24 hours.
The trick is thorium-229, whose nucleus has two energy states separated by an unusually small gap, small enough for a UV laser to flip it. The laser excites the thorium nuclei, and the nuclei in turn keep the laser's frequency in check. When absorption drops, the system readjusts automatically. Interesting Engineering reports a precision of 10^-15 over 24 hours, which works out to about one second of error every 30 million years.
Why Nuclei Beat Electrons
Today's atomic clocks rely on electrons, which are fairly easy to disturb. Atomic nuclei are smaller and much better shielded from outside interference, so in principle a nuclear clock can be far more precise. Possible uses include mapping gravitational variations underground, improving navigation for deep-space missions, and testing whether the fundamental constants of physics change over time.
To be fair, this isn't a victory lap yet. The prototype hasn't matched the best optical atomic clocks, a preliminary dark-matter search found no significant signal, and the team says it needs stronger lasers and better thorium crystals. What it does show is that a nuclear clock can run autonomously, which is the step needed to move from a lab demo to real infrastructure.
The time is coming, give or take a second every 30 million years.
Precision matters on the web too, if not quite to nuclear standards, and if your platform's updates and integrations keep drifting out of sync, we'd be glad to help get things running like clockwork.
Source: Interesting Engineering