South African astronomers have achieved a major breakthrough in radio astronomy after discovering the most distant hydroxyl megamaser ever detected, providing an unprecedented glimpse into a period when the universe was less than half its current age.
The discovery was made using the MeerKAT radio telescope in the Northern Cape and centres on a powerful natural radio signal originating from a galaxy located more than eight billion light-years from Earth. The signal, known as a hydroxyl megamaser, was emitted during a violent merger between galaxies at a time when the cosmos was far younger and significantly more active than it is today.
Researchers say the finding offers a rare opportunity to study how galaxies evolved during one of the most dynamic periods in the history of the universe. Because light from the galaxy took more than eight billion years to reach Earth, astronomers are effectively observing the system as it existed billions of years ago, long before the formation of many of the structures visible in the modern universe.
The research was led by scientists including Thato Manamela, a postdoctoral researcher at the University of Pretoria, and Professor Roger Deane, Director of the Inter-University Institute for Data Intensive Astronomy (IDIA) and a professor at both the University of Cape Town and the University of Pretoria.
What makes the discovery particularly remarkable is not only the record-breaking distance of the megamaser but also the speed with which it was detected. Scientists identified the signal in just five hours of observation time, despite such discoveries typically requiring hundreds of hours of telescope observations.
The detection was made possible by MeerKAT’s exceptional sensitivity and wide frequency coverage, which allow astronomers to search vast regions of space for faint radio signals. The telescope’s advanced capabilities enabled researchers to identify both hydroxyl emissions and neutral hydrogen signatures within the same observation, dramatically increasing the efficiency of the search.
The signal was further amplified by a phenomenon known as gravitational lensing, where the gravity of a massive foreground object bends and magnifies light and radio waves from a more distant source. This natural magnification effectively transformed the intervening galaxy into a giant cosmic lens, boosting the signal enough for MeerKAT to detect it.
Scientists believe the discovery marks the beginning of a new era in radio astronomy. It suggests that future surveys conducted by MeerKAT and the upcoming Square Kilometre Array Observatory (SKAO) could uncover large numbers of similarly distant and previously hidden cosmic objects.
Hydroxyl megamasers are commonly associated with galaxy mergers, environments where intense bursts of star formation occur and where supermassive black holes may eventually collide. Such mergers are considered critical stages in the evolution of galaxies and can ultimately produce gravitational waves, ripples in space-time first predicted by Albert Einstein and detected directly for the first time in 2015.
By identifying systems like these across vast stretches of cosmic history, astronomers hope to better understand how galaxies grow, how black holes interact and how some of the universe’s most energetic events unfold.
The discovery also underscores South Africa’s growing influence in global astronomy and data-intensive scientific research. MeerKAT has already established itself as one of the world’s most powerful radio telescopes, while institutions such as IDIA continue to develop the advanced computing infrastructure required to process the enormous volumes of data generated by modern astronomical observations.
Researchers say the achievement demonstrates that South Africa is not only contributing to major scientific discoveries but is also helping shape the future of radio astronomy ahead of the full rollout of the Square Kilometre Array, which is expected to become the world’s largest and most sensitive radio observatory.
As astronomers continue to push deeper into the cosmos, discoveries such as this are opening new windows into the universe’s distant past, revealing chapters of cosmic history that have remained hidden for billions of years.