It’s about (bloody accurate) time!
The next generation of mind-brreakingly accurate clocks are here. Tick Tock, NerdNews rocks.
Sign of the time.
I love a good watch as much as the next man.
I’ve got a cracking Seiko, given to me by one of my best mates for my 50th birthday, that I wear whenever I want to look impressive.
I’ve got a Garmin Fenix 6, capable of collecting phenomenal amounts of data about my health and fitness.
I use it to count my steps.
And I’ve got an old gold (plated, I assume) watch that my dad’s dad used to wear. I pop it on occasionally for the memories, despite the fact that it is awful, these days, at keeping the time.
But hey, let’s ask a question. Exactly how well does a watch, or any timepiece for that matter, need to keep time?
Would you really notice if your watch lost a second a day? A week? A year? A century?
“It is not that we have a short space of time, but that we waste much of it.” — Seneca, Roman philosopher, On the Shortness of Life, first century AD.
Well, in early October, news dropped of a new generation of clocks, the best prototypes of which demonstrate stability equivalent to losing just one second in tens of millions of years.
Full disclaimer. We’ve already got atomic clocks that are WAY more accurate than that.
The best can theoretically lose less than a second in tens of billions of years.
But the kicker with these new timepieces is that, if we get them right, they may well eventually eclipse the most accurate clocks humanity has ever devised.
Working like (atomic) clockwork.
Atomic clocks are nothing new. We’ve had them for more than 70 years.
At the heart of atoms, and how they function, are incredibly consistent and predictable processes ticking along. In particular, electrons can jump between different energy levels when exposed to electromagnetic radiation of precisely the right frequency.
And those frequencies are fantastically reliable.
Ever since Harold Lyons and his team harnessed the behaviour of ammonia molecules to build the first atomic clock in 1948, we’ve just kept sharpening our stopwatch.
From the caesium clocks that still give us the official definition of a second, to the aluminium-ion-powered beast unveiled in 2025 that measured time to a staggering 19 decimal places, our timekeeping technology has become almost unimaginably accurate.
And throughout that journey, we’ve relied on transitions between energy states in atoms or molecules, overwhelmingly involving the behaviour of electrons.
But that’s all about to change.
“Every second counts.” — The Bear, television series.
Going deep into the guts.
Time never stands still for a cutting-edge clockmaker. They’re always craving more accuracy.
And to achieve that, we’ve now jumped from the outer shell of atoms, where electrons beat their drum, into the very heart of the atom itself.
The nucleus.
Turns out there’s a beat in there so regular it could make an electron look like it’s had a couple of drinks and is stumbling home.
At the heart of an atom of thorium-229 lies its nucleus, a collection of 90 protons and 139 neutrons, which normally sits in its lowest-energy state. Just humming along. But it can be excited into a slightly higher-energy state by absorbing a photon of ultraviolet light with precisely the right amount of energy.
The difference between those two states is about 8.4 electronvolts.
Which, trust me, really isn’t much. Especially, as it turns out, for the difference in energy states of a nucleus.
And it is this minute difference in energy levels that these new clocks look to exploit.
Usually, nuclear energy transitions require immensely energetic radiation. But thorium-229 has this extraordinarily small energy gap, meaning scientists can trigger the transition using a specially tuned ultraviolet laser.
Shine that laser through a crystal containing thorium-229 and, when its frequency is just right, some of the nuclei absorb the light and jump to their excited state.
The trick is that the nuclei effectively tell us when the laser is bang on the correct frequency.
If the laser drifts, the amount of light absorbed changes. Electronics detect that change and adjust the laser back to where it should be.
We then count the incredibly rapid oscillations of that laser to measure time.
So the nucleus tells us when the laser is perfectly tuned and that laser then makes the clock tick.
And because a nucleus is vastly smaller than an atom and relatively protected from disturbances in the outside world, those ticks could eventually be more reliable than anything we’ve managed using electrons.
Two independent teams, one in Europe and one in China, have shown this process to work in an actual clock.
Their results were published in Nature on 7 October.
The European clock operated for more than 24 hours without intervention. And the two experimental approaches have complementary strengths that could help researchers make the next generation dramatically better.
“This is not yet at the level of the world’s best optical atomic clocks, but for a first prototype it is a fantastic result.” — Thorsten Schumm, nuclear clock researcher, Vienna University of Technology.
Time to get dark.
And what would we actually DO with a clock this precise?
Yes we can improve on the already incredibly accurate way we measure time in navigation, telecommunications and synchronising complex computer systems.
We might also detect tiny changes in gravity.
But where this gets really exciting for some space nerds is the light it may shed on dark matter (pun fully intended).
That mysterious invisible stuff we think makes up about 85% of all the matter in the Universe, but still haven’t managed to identify.
Some theories suggest dark matter could cause the fundamental constants of nature to fluctuate ever so slightly.
Now, nuclear clocks and conventional atomic clocks depend on different physical processes.
So if some form of dark matter were to subtly change those processes, the two clocks might tick differently.
By comparing them, scientists could potentially catch dark matter red-handed.
In fact, the European team has already tried.
They compared their new nuclear clock with a conventional atomic clock, hunting for tiny variations that might reveal certain hypothetical dark matter particles.
They didn’t find any.
But they did place new limits on some possibilities that had previously remained open.
And that’s a pretty impressive first outing for a technology that’s barely out of the laboratory.
We’ve gone from watching the Sun rise, to pendulums swinging, to electrons changing energy levels, and now to the very heart of the atom.
All in our relentless pursuit of knowing exactly what time it is.
Anyway, is that the time? I’ve gotta go hit that step target. Cheers.
Further reading:
Original research:
• Toscani De Col et al. (2026), A thorium-229 optical nuclear clock with feedback loop, Nature.
• Huang et al. (2026), A nuclear clock synchronized to ²²⁹Th, Nature.
Accessible reporting:
• Akio Kawasaki (2026), Nuclear clocks tick for the first time, Nature.
• American Physical Society (2026), First Nuclear Clocks Kick Off a Precision Race.
• Ellen Phiddian (2026), Nuclear clocks could become world’s most accurate timekeepers, ABC Science.
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