Two teams of researchers, one in Beijing and one in Vienna, have each built a nuclear clock based on thorium-229, and studies indicate the Chinese device is the more stable of the two, according to South China Morning Post. The work marks the first time stand-alone nuclear clocks have been shown to tick, reports from the outlets covering the research say.
The South China Morning Post headline states that China's thorium-229 clock beats Vienna's on stability. Other outlets, including Reuters, The New York Times and Phys.org, reported that scientists in both cities had created the world's first nuclear clocks, with Phys.org describing Vienna's as the first stand-alone device.
A nuclear clock keeps time using transitions in the nucleus of an atom rather than the electron shell transitions used by today's atomic clocks. Thorium-229 is central to the effort because it has an unusually low-energy nuclear transition that can be driven with lasers. Coverage from IFLScience framed the devices as a new tool for probing fundamental forces and for the hunt for dark matter.
Because only headlines and summaries of the studies are available, the precise stability figures behind the comparison have not been detailed here.
What to watch next: whether the two teams publish full measurements that allow the stability claims to be compared directly.
