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China's 'Sky Eye' Captures First Case of Naturally Evolving Pulsar Triple System, Nuclear Optical Clock Debuts
China's FAST (Five-hundred-meter Aperture Spherical radio Telescope) and the field of quantum precision measurement have simultaneously achieved two landmark breakthroughs: FAST has discovered the first pulsar triple system still in its evolutionary phase, and a team from Tsinghua University has pioneered the development and stable operation of a 'nuclear optical clock' internationally. FAST Locks Onto a 'Living Triple System'. A research team led by Professor Han Jinlin from the National Astronomical Observatories, combining FAST radio data with multi-band astronomical archives, has revealed that pulsar J0435+3233 belongs to the first naturally evolving triple system. The findings were published in The Astrophysical Journal Letters. This pulsar has a spin period of only 3.2 milliseconds and orbits a white dwarf with a period of 8 days; its spin period increases by 1 nanosecond annually, an anomalous rate two orders of magnitude higher than similar pulsars. The team further identified a third companion star—a solar-type star with a mass comparable to the Sun—orbiting the binary system in a highly eccentric orbit (eccentricity 0.6) with a period of 73.5 years. According to evolutionary theory, this system originated from a 'triplet' formed from the same cloud: the most massive 'elder brother' has evolved into a pulsar, the 'second brother' became a white dwarf, and the 'third brother', not yet affected by a supernova, is still in a stable evolutionary stage, making it a rare 'living triple system' to date. A Sino-European team independently confirmed this conclusion, with the orbital parameters determined by the Chinese team being one order of magnitude more precise than those of the European team. 'Nuclear Optical Clock' Opens New Timing Paradigm. A team led by Ding Shiqian at Tsinghua University utilized a self-developed 148-nanometer continuous-wave vacuum ultraviolet laser and a thorium-229-doped calcium fluoride crystal to lock the laser frequency to the transition of the thorium-229 atomic nucleus, achieving this internationally
2026.10.20 PM 8:27 · View Count 2
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AuthorChina has become the first in the world to achieve stable operation of a nuclear optical clock, with the results published online in 'Nature'. While atomic clocks measure time by 'listening to the beat of electrons,' nuclear optical clocks place the 'pendulum' inside the atomic nucleus, ticking approximately 2,000 trillion times per second, achieving precision far exceeding traditional atomic clocks. Because atomic nuclei are less susceptible to external electromagnetic disturbances, nuclear optical clocks are expected to provide a higher-precision and potentially miniaturized time-frequency standard, paving new paths for satellite navigation, deep space exploration, and even the verification of fundamental physical laws. From the three-body orbit on a cosmic scale to the quantum beat at the scale of atomic nuclei, these two breakthroughs jointly mark China's substantial progress at the forefront of fundamental observation and precision measurement.