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Scientists have invented an entirely new kind of clock.
The first ever working nuclear clocks could help us better understand dark matter and other fundamental questions of the universe, according to scientists.
For more than 70 years, scientists have been using atomic clocks, which measure time by tracking electrons as they switch between energy states, as an astonishingly precise measure of time. That in turn has allowed for all kinds of breakthroughs: they have allowed for technology such as GPS, as well as grander experiments such as showing that time behaves differently in different parts of space.
Now, the scientists behind the new breakthrough say they have come up with a new and even more precise technology. The nuclear clocks work by monitoring how light interacts with an atomic nucleus.
They could be used for instance to detect the presence of a form of dark matter, the mysterious and invisible material that makes up much of the universe. That shows how the nuclear clock could be used to probe fundamental questions of the physics of the universe in other ways, scientists away from the research said.
The nuclear clocks also help overcome some of the limitations of atomic clocks. External electric fields can affect their operation, for instance, and make them less reliable.
Atomic nuclei, however, are about 100,000 times smaller than atoms and are therefore less sensitive to those electric fields. That could make the nuclear clocks more reliable, the teams behind them say.
The work builds in a 2003 proposal that suggested that atomic nuclei could be a particularly accurate way of building clocks, and suggested that thorium-229 could be a useful material to make them out of because it is in a low energy state that makes it easier to track its transitions.
But the clocks do still come with problems. Although they were able to hold their time, they are less stable than the best atomic clocks.
But the researchers behind the breakthrough say that further work could help overcome those problems. That might involve building them with much more powerful lasers.
The work is reported in two new papers, ‘A thorium-229 optical nuclear clock with feedback loop’ and ‘A nuclear clock synchronized to 229Th’, both published in the journal Nature.