All clocks lie. They do it in silence, with almost perfect, but inevitable, discretion. Whether it’s the one on the cell phone, the one on the oven or the one we carry on our wrist, they all lose or gain small fractions of time. Seconds that slip away, minutes that go by. Nothing noticeable on a day-to-day basis, but enough to remind you of an uncomfortable truth: Measuring time with absolute accuracy is actually impossible.. Or at least it was.
A new optical clock developed at the University of Science and Technology of China, under the direction of physicist Pan Jianwei, has taken this precision to a limit that is difficult to imagine: would lose or gain less than a second in about 30 billion years. That is, more than double the age of the universe.
To understand why this is extraordinary, it’s worth starting with a simpler question: why do clocks waste time? The answer has to do with real-world physics. Traditional clocks, even the most advanced ones, depend on systems that oscillate: a pendulum, a quartz crystal, or the vibrations of atoms. But none of those oscillations are perfectly stable. Temperature, external vibrations, electromagnetic fields and even small imperfections in materials introduce deviations. Tiny letters, yes, but inevitable.
Even atomic clocks, those that define the second official by measuring the radiation frequency of atoms such as cesium, have a margin of error. AND in a world where GPS satellites, telecommunications networks or physics experiments depend on extreme synchronizationthose mistakes start to matter.
That’s where optical watches come in. Instead of relying on microwaves, like traditional atomic clocks, these devices use visible light frequencies, which oscillate much faster. It’s like going from counting seconds with a metronome than doing it with a vibration thousands of times faster: the faster the reference, the greater the precision.
The watch developed by the Jianwei team It uses strontium atoms trapped in an optical network (a kind of “light filter”) and measures their energy transitions with extraordinary accuracy. Its two key parameters, stability and uncertainty, have reached levels of the order of 10⁻¹⁹. in tandsimple terms: it is one of the mosttos stable jamtos built.
Obviously, the implications go far beyond watchmaking. Clocks of this precision would allow us to improve satellite navigation systems, make communications more secure and, above all, explore new frontiers of physics. For example, could detect minute variations in Earth’s gravity, which would allow mapping the planet’s interior with unprecedented precisionor even test fundamental theories such as Albert Einstein’s relativity.
In fact, at these levels of accuracy, time is no longer uniform. A clock placed one meter high may move at a slightly different speed than one on the ground, due to gravity. It is an effect predicted by relativity, but only visible when precision reaches extremes like this.
And perhaps therein lies the most fascinating thing about this achievement. It is not just about building a better clock, but about discovering that time, that concept that seems so stable, it is actually something malleable, dependent on place, speed… and our ability to measure it.
Because the more we tune our instruments, the more evident a paradox becomes: it’s not that clocks lie less. The thing is We increasingly understand the extent to which time was never as simple as we believed.