China’s Sky Eye: A Decade of Cosmic Signal Decoding

China’s Five-hundred-meter Aperture Spherical Radio Telescope (FAST), the world’s largest single-dish radio telescope, has reached a landmark decade of operation, transforming humanity’s ability to decode cosmic signals from the depths of the universe. Since its completion in September 2016, the instrument—known as “China’s Sky Eye”—has discovered 1,284 pulsars, far exceeding the combined total found by all other radio telescopes worldwide during the same period, according to Xinhua News.

A Decade of Extraordinary Discovery

The telescope’s scientific output has exceeded all expectations. On October 10, 2017, just over a year after FAST became operational, the National Astronomical Observatories of the Chinese Academy of Sciences announced the detection of dozens of high-quality pulsar candidates, with six confirmed—marking the first pulsars ever discovered by a Chinese radio telescope.

Since then, the discoveries have accelerated dramatically. FAST’s 1,284 pulsars include more than 170 millisecond pulsars and over 160 pulsar binary systems, including the shortest-known orbital period pulsar binary system at just 53 minutes. As China Daily reported, the telescope surpassed 1,000 pulsar discoveries in late 2024, already exceeding the total number found by all other international telescopes over the previous seven years.

Beyond pulsars, FAST has made significant contributions across multiple frontiers of astrophysics. In the competitive field of nanohertz gravitational wave detection, the telescope’s ultra-high sensitivity can improve pulsar timing precision to 4-50 times previous global levels, potentially enabling the first-ever detection of the nanohertz gravitational wave background. The telescope has also completed lunar orbit and near-Earth asteroid observation missions, improving lunar surface imaging resolution from 50 meters to 20 meters.

Unlocking the Mystery of Fast Radio Bursts

One of FAST’s most dramatic achievements came in January 2026, when an international research team led by astronomers from the Purple Mountain Observatory of the Chinese Academy of Sciences published first-ever evidence supporting a binary-system origin for at least some fast radio bursts (FRBs)—among the most enigmatic phenomena in modern astrophysics. The findings, published in the journal Science, were based on continuous monitoring of the repeating FRB 20220529, located 2.9 billion light-years away, as Global Times reported.

The team detected a dramatic surge in the burst’s Faraday rotation measure—a precise probe of cosmic magnetic environments—to roughly 20 times its average variability in December 2023, before it returned to normal within two weeks. This rapid, reversible change cannot be explained by existing theories if the FRB originated from an isolated neutron star, but fits naturally within a binary system scenario.

“It is a remarkable result,” said Duncan Lorimer, a professor of Physics and Astronomy at West Virginia University, adding that it demonstrates “the power of the FAST radio telescope in China, to make these monitoring observations.”

New Insights into Cosmic Evolution

On September 1, 2026, an international team including researchers from the National Astronomical Observatories and Shanghai Astronomical Observatory published a landmark study in Nature Astronomy using FAST combined with the Dark Energy Spectroscopic Instrument (DESI). The research analyzed approximately 2.5 million galaxies across one-third of the sky to trace the evolution of neutral hydrogen—the essential fuel for star formation—over the past 4.5 billion years, as CGTN reported.

The precise measurements revealed that while the cosmic star formation rate 4.5 billion years ago was about 2.5 times today’s level, the density of neutral atomic hydrogen was only about 1.4 times its current value. This finding directly rules out the simplistic scenario that rapid exhaustion of neutral hydrogen caused the decline in star formation, offering new clues to one of astronomy’s most perplexing questions.

Full Domestic Technology Replacement

Behind the scientific breakthroughs lies a decade-long effort to achieve full technological self-reliance. As CGTN reported, FAST completed the replacement of six giant steel cables—nearly 4,000 meters in total length—with domestically produced equivalents in 2026. The cables, which support and control the telescope’s 30-tonne feed cabin, had previously relied on German imports.

“FAST is like an eye, and the 6 steel cables are like the 6 muscles of the eyeball,” said Yao Rui, director of the Measurement and Control Engineering Department at the FAST Operations and Development Center. The domestic cables, developed over three years with extensive testing including 62,000 repeated pulley operations and 200,000 pulse fatigue tests, cost nearly half as much as their imported predecessors while achieving equivalent performance.

This achievement is part of a broader localization effort. All 2,225 actuators that drive the telescope’s reflective surface have been fully localized since 2020, a domestically developed microwave ranging system entered trial use in April 2026, and the L-band low-noise amplifier has achieved international first-class noise levels—even being exported to Brazil.

“In the past, we long pursued a ‘borrowing approach,’ but the special needs of frontier astronomical research often have no mature commercial equipment available,” said Jiang Peng, deputy director of the National Astronomical Observatories and chief engineer of FAST. “Relying on imports always carries three hidden dangers: supply chain disruption, environmental adaptation, and maintenance costs.”

Global Recognition and the Road Ahead

FAST’s impact has resonated across the international scientific community. Renowned Polish astronomer Aleksander Wolszczan, who made the first confirmed discovery of planets outside our solar system, told Xinhua that “FAST is now the pulsar radio telescope,” describing it as “bigger, more sensitive” than the now-collapsed Arecibo Observatory. “The global community needs China,” he said.

Looking forward, FAST Phase II is already underway. The project plans to construct the world’s first giant telescope-centered hybrid aperture radio interferometric array, with 24 additional 40-meter antennas deployed within 5 kilometers of the main telescope. This innovative design will combine FAST’s unmatched sensitivity with high angular resolution, overcoming the fundamental trade-off between sensitivity and resolution that limits single-dish telescopes.

“The upgraded FAST will have irreplaceable competitiveness in frontier fields such as cosmic origins, neutral hydrogen galaxy evolution, dark energy properties, and gravitational wave detection,” Jiang Peng said.

As China’s Sky Eye enters its second decade, it continues to search the cosmos for signals that could reshape our understanding of the universe. With its scientific output accelerating, its technology fully self-reliant, and its next-generation expansion underway, FAST stands poised to remain at the forefront of humanity’s exploration of the cosmos for years to come.