Analysis: Science & Technology — 09 October 2026
Vienna and Beijing teams operate first thorium-229 nuclear clocks
Two independent groups reported in Nature the first working nuclear clocks, locking ultraviolet lasers to a transition inside thorium-229 nuclei embedded in calcium fluoride crystals. The Tsinghua-led Beijing device and the TU Wien–PTB Vienna device reached the milestone at the same time with different hardware: China used a stronger laser and far less thorium; Europe used a denser crystal. Measured instabilities correspond to roughly one second in 3 million years (Vienna) and 19 million years (Beijing), still far behind the best optical atomic clocks.
Atomic clocks time electron energy jumps. Thorium-229 is the only known nucleus with a laser-accessible isomer near 148.4 nanometres, so the oscillator sits in the nucleus, which is far smaller and more tightly bound than an electron shell. Physicists have pursued this approach for about 50 years. Beijing found two separately grown crystals agreed to about three parts in 10 trillion; Vienna ran a clock for more than 24 hours against an optical atomic clock and used it in a null dark-matter search.
The devices remain proof-of-concept. Researchers say combining Vienna’s crystals with Beijing’s laser would improve performance, and current limits are technical rather than fundamental. Whether nuclear clocks can match trapped-atom optical clocks, or constrain variations in fundamental constants, is still open.
Sources: APS Physics, Reuters, EurekAlert, MIT Technology Review.
Einstein Probe records ten minutes of soft X-rays after a short gamma-ray burst
Einstein Probe’s wide-field X-ray telescope caught event EP250704a/GRB 250704B: a sub-second gamma-ray flash followed by nearly ten minutes of energetic soft X-rays. Conventional gamma-ray monitors such as Swift’s BAT would have seen only the brief flash. Follow-up across X-ray, optical and radio bands tied the event to a compact-object merger and ruled out a supernova.
Short GRBs are the electromagnetic signature of neutron-star mergers, which also emit gravitational waves. Narrow-field X-ray telescopes usually slew after a gamma-ray alert and miss the earliest soft X-ray phase. The prolonged emission appears to come from a long-lived central engine, possibly a newborn magnetar, rather than the blast wave.
If this soft X-ray tail is common, many past short GRBs were incompletely observed. The signal is proposed as a new electromagnetic counterpart to gravitational-wave sources. Whether the remnant is a magnetar, and whether the data can constrain the neutron-star equation of state, remains unproven.
Sources: ScienceDaily, Science China Press, Science Bulletin.
NASA selects three payloads to hunt lunar caves, ice and surface hazards
NASA chose three PRISM investigations for delivery by commercial CLPS landers under its Moon Base program. GIMLI will probe the Marius Hills Pit with geophysics to test whether the skylight opens into a lava tube. DISCO aims for the first surface measurements of ice in micro-cold traps. LEMS-SP will run an autonomous south-polar station for moonquakes, micrometeoroids and volatiles.
Lava tubes could offer stable temperatures and shielding from radiation and impacts. Ice could supply water, oxygen and hydrogen without hauling mass from Earth. Surface seismicity, exhaust-blown dust and terrain stability will constrain habitat siting.
None of the payloads has flown yet. A pit does not guarantee a usable cave, and ice in micro-cold traps may be too sparse or mixed with regolith to exploit. How these data will set Moon Base architecture is not yet decided.
Sources: ScienceDaily, NASA.