China’s FAST and South Africa’s MeerKAT Join Forces to Unlock New Secrets of the Milky Way

In a groundbreaking international collaboration, astronomers from China’s Tsinghua University, along with scientists from Italy, Australia, Germany, and other nations, have used two of the world’s most advanced radio telescopes, China’s Five-hundred-meter Aperture Spherical Radio Telescope (FAST) and South Africa’s MeerKAT array, to conduct unprecedented observations of globular clusters, some of the Milky Way’s oldest and most mysterious star systems. Their findings, reported by China Central Television (CCTV), provide the most detailed measurements yet of magnetic fields and gas within these clusters, reshaping our understanding of how they evolve and how our galaxy’s magnetism works.  

A Cosmic Collaboration  

Globular clusters are dense, spherical collections of millions of stars, some as old as the universe itself. Among them are pulsars, rapidly spinning neutron stars that emit beams of radio waves like cosmic lighthouses. By studying these pulsars, scientists can detect subtle changes in their signals as they travel through space, revealing information about the magnetic fields and gas they pass through.  

FAST, the world’s largest single-dish radio telescope, is uniquely suited to picking up faint pulsar signals from deep space. Meanwhile, MeerKAT, with its 64 interconnected antennas, excels at mapping broader areas of the sky and detecting tiny shifts in signal polarisation caused by interstellar gas. Together, they form a powerful duo, allowing researchers to observe globular clusters with unprecedented precision.  

Read the findings in ScienceDirect Bulletin – “Probing globular cluster with MeerKAT and FAST: a pulsar polarisation census”

Surprising Discoveries: “Cleaner” Than Expected  

The team studied 43 pulsars across eight globular clusters, measuring their polarisation and magnetic field effects in detail. Surprisingly, they found that seven of these clusters contained almost no detectable ionised gas, far less than theoretical models predicted.  

“We expected these clusters to be filled with gas, but they’re surprisingly ‘clean,’” said Dr Zhang Lei, the lead data analyst on the project, in an interview with CCTV. “This means something, possibly radiation from white dwarfs and young stars, is efficiently clearing out the gas, which challenges our current theories on how these clusters evolve.”  

The findings, published in a ScienceDirect Bulletin study, also doubled the known measurements of magnetic field rotations in these clusters and improved the accuracy of gas density readings by eight times (8x) compared to previous studies.  

What’s Next?  

This collaboration marks just the beginning. According to CCTV, FAST and MeerKAT will continue working together to:  

• Monitor “glitches” in pulsars (sudden changes in their rotation).  
• Study turbulent interstellar gas to better understand galaxy formation.  
• Search for potential extraterrestrial signals as part of broader cosmic exploration efforts.  

Why This Matters  

Understanding globular clusters helps scientists piece together the history of the Milky Way, as these ancient star systems act as time capsules from the early universe. The discovery of their unexpectedly low gas content suggests that current models of star cluster evolution may need revising, opening new doors for astrophysical research.