Lizzie Gibney

But now what we have, which was new earlier this month,

is a completely different way of doing this.

So rather than getting your tick from the energy levels of electrons, this plot gets them from the energy levels of nuclei.

So the nucleus of thorium-229.

Exactly.

So nuclei have energy levels, and that comes from the different configurations that you can have of their protons and neutrons.

And thorium is very unusual in it that it has these two energy levels that are very close together.

So with a laser, you can actually nudge that in the lab.

And two teams have now done that.

So for scientific reasons is a big one.

So what's quite exciting about this particular clock is that the way that it's made, the fact that you're using these nuclear energy levels, lots of different kinds of dark matter predicted that they would mess with the forces that bind the nucleus.

So if we are basically studying these nuclear energy levels, you can look for the effects of dark matter, changing the strength of fundamental forces, because that would also then change the tick speed.

So one use is fundamental physics.

But another is that actually, you know, the best clocks that we have that are, I think, you know, is one to...

what, they lose a second over 40 billion years.

You know, they're inside labs.

They take extreme cooling and control.

But what we'd love to be able to do is have really precise clocks that you can take out into the field to do navigation and communications.

Nuclear clocks are really, really robust because not only is your clock actually inside like a tiny crystal, but it's just much harder to disturb a nucleus than it is electrons.

So they are very, very sturdy and could make for much more portable and robust kind of precise clocks.